Radiation-sensitive linear resin composition and pattern formation method

Abstract

This invention provides a radiosensitive linear resin composition and a patterning method that can fully utilize sensitivity, CDU performance, and developer residue performance when applying next-generation technologies. A radiosensitive linear resin composition includes: a radiosensitive linear acid-generating resin comprising a structural unit A having an acid-dissociating group and a structural unit D having a phenolic hydroxyl group; and a solvent, wherein the structural unit D has a phenolic hydroxyl group and an alkyl group on the same aromatic ring, and an alkyl group is bonded to an adjacent carbon atom of the carbon atom to which the phenolic hydroxyl group is bonded in the aromatic ring of the structural unit D. The radiosensitive linear resin composition further satisfies at least one of the group consisting of conditions 1 and 2 below. Condition 1: The resin is a radiosensitive linear acid-generating resin further comprising a structural unit B, wherein the structural unit B includes an organic acid anion moiety and an onium cation moiety comprising an aromatic ring structure having a fluorine atom. Condition 2: Further includes onium salts (excluding the radiosensitive linear acid generating resin), wherein the onium salts include an organic acid anion moiety and onium cations comprising an aromatic ring structure having fluorine atoms.

Description

Technical Field

[0001] This invention relates to a radiosensitive linear resin composition and a method for patterning. Prior Technology

[0002] Photolithography, using photoresist compositions, is employed in the formation of fine circuits within semiconductor devices. A representative process involves irradiating a photoresist film with radiation to generate acid, and then using this acid as a catalyst to create a difference in solubility relative to the developer in 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 is used, or this radiation is combined with liquid immersion lithography to advance pattern miniaturization. As a next-generation technology, the use of even shorter-wavelength radiation such as electron beams, X-rays, and extreme ultraviolet (EUV) radiation is being explored, and resist materials containing acid-generating agents with benzene rings that improve the absorption efficiency of these radiations are also being investigated (Patent Document 1). [Existing Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2014-2359 Summary of the Invention

[0005] [The problem that the invention aims to solve] In the next-generation technology, the same or better performance of the resist as before is required in terms of sensitivity, critical dimension uniformity (CDU) as an indicator of linewidth or aperture uniformity, and low development residue.

[0006] The purpose of this invention is to provide a radiosensitive linear resin composition and a patterning method that can fully utilize the sensitivity or CDU performance and development residue performance when applying next-generation technologies. [Methods for solving problems]

[0007] The inventors repeatedly studied the problem to solve it, and found that the objective could be achieved by adopting the following structure, thus completing the present invention.

[0008] In one embodiment, the present invention relates to a radiosensitive linear resin composition, comprising: The resin comprises structural unit A having an acid-dissociable group and structural unit D having a phenolic hydroxyl group; and Solvent, The structural unit D has a phenolic hydroxyl group and an alkyl group on the same aromatic ring. In the aromatic ring of the structural unit D, an alkyl group is bonded to the carbon atom adjacent to the carbon atom to which the phenolic hydroxyl group is bonded. The radiosensitive linear resin composition further satisfies at least one of the group consisting of the following conditions 1 and 2. Condition 1: The resin is a radiosensitive linear acid-generating resin that further includes structural unit B, wherein structural unit B includes an organic acid anion portion and an onium cation portion comprising an aromatic ring structure having fluorine atoms. Condition 2: Further includes an onium salt (excluding the radiosensitive linear acid generating resin), the onium salt comprising an organic acid anion moiety and an onium cation moiety comprising an aromatic ring structure having a fluorine atom.

[0009] This radiosensitive linear resin composition can be used to construct a resist film that satisfies the requirements for sensitivity, CDU performance, and development residue. While the rationale is uncertain, it is speculated as follows: The absorption of EUV and other radiation at a wavelength of 13.5 nm caused by fluorine atoms is very large, thus enabling high sensitivity in the radiosensitive linear resin composition. Furthermore, the acid dissociation efficiency of the acid-dissociating groups in structural unit A of the resin is high due to exposure, thereby increasing the contrast between the exposed and unexposed areas and resulting in excellent patterning properties. It is speculated that the aforementioned resist properties are achieved through the combined effect of these factors.

[0010] In another embodiment, the present invention relates to a pattern forming method, 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.

[0011] In this pattern forming method, since the radiosensitive linear resin composition with excellent sensitivity, CDU performance and developing residue performance is used, high-quality resist patterns can be formed efficiently. Simple Explanation of the Diagram

[0012] none Implementation

[0013] The embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments.

[0014] <Radiation-sensitive linear resin composition>

[0015] The radiosensitive linear resin composition of this embodiment (hereinafter, also simply referred to as the "composition") comprises a resin and a solvent. The composition may also contain any other ingredients as long as it does not impair the effects of the present invention. By containing the specified resin, the radiosensitive linear resin composition can impart high levels of sensitivity, CDU performance, and developer residue properties to the obtained resist film.

[0016] <Resin> The resin is an aggregate (G1) of polymers comprising structural unit A having an acid-dissociable group, structural unit B containing an anionic portion of an organic acid radical and an onium cationic portion containing an aromatic ring structure with a fluorine atom, and structural unit D having a phenolic hydroxyl group; or an aggregate (G2) of polymers comprising structural unit A having an acid-dissociable group and structural unit D having a phenolic hydroxyl group; or an aggregate comprising both aggregate (G1) and aggregate (G2) (hereinafter, these polymers (G1) and polymer (G2) are also referred to as "base resin"). In aggregate (G1) and aggregate (G2), structural unit D has a phenolic hydroxyl group and an alkyl group on the same aromatic ring, and an alkyl group is bonded to the carbon atom adjacent to the carbon atom bonded to the phenolic hydroxyl group in the aromatic ring of said structural unit D. In addition to structural units A, B, and D, the base resin may also include structural units E containing lactone structures or other structural units. The structural units will be described below.

[0017] (Structural Unit A) Structural unit A (hereinafter also referred to as "structural unit A") is preferably the structural unit represented by the following formula (1).

[0018] [Chemistry 1] (in the above formula (1), RT can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; RX is a monovalent hydrocarbon group with 1 to 20 carbon atoms; Cy represents an alicyclic structure with 3 to 20 ring members formed together with the carbon atoms it is bonded to.

[0019] Examples of monovalent hydrocarbon groups with 1 to 20 carbon atoms represented by RX 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.

[0020] Examples of the chain hydrocarbon groups having 1 to 10 carbon atoms include straight-chain or branched-chain saturated hydrocarbon groups having 1 to 10 carbon atoms, or straight-chain or branched-chain unsaturated hydrocarbon groups having 2 to 10 carbon atoms.

[0021] Examples of 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. 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 by a linker group containing one or more carbon atoms.

[0022] 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.

[0023] As RX, it is preferably a straight-chain or branched-chain saturated hydrocarbon group with 1 to 5 carbon atoms, an alicyclic hydrocarbon group with 3 to 12 carbon atoms, or an aromatic hydrocarbon group with 6 to 10 carbon atoms. In the case of an aromatic hydrocarbon group with 6 to 10 carbon atoms, it is also preferable that part of the hydrogen atom of the aromatic hydrocarbon group is substituted with a halogen atom.

[0024] The alicyclic structure with 3 to 20 ring members in Cy is not particularly limited as long as it has an alicyclic structure. It can have monocyclic, bicyclic, tricyclic, tetracyclic or more polycyclic structures, and can also be a bridged ring structure, a spirocyclic structure, a ring aggregate structure in which multiple rings are directly bonded by single or double bonds, or any combination thereof. Among them, it is preferred to have a bridged ring structure with monocyclic, bicyclic, tricyclic or tetracyclic, and more preferably a monocyclic cycloalkyl ring structure such as cyclopentane or cyclohexane; and a polycyclic cycloalkyl ring structure such as norbornene, adamantane, tricyclic [5.2.1.0 2,6]decane, tetracyclic [4.4.0.1 2,5.1 7,10]dodecane, perhydronaphthalene, perhydroanthracene, etc.

[0025] The structural unit represented by equation (1) is preferably represented by, for example, the following equations (A-1) to (A-8).

[0026] [Chemistry 2]

[0027] In equations (A-1) to (A-8), RT and RX have the same meaning as in equation (1). Preferably, structural unit A is represented by, for example, equations (A-1), (A-4), (A-5), (A-6), and (A-8).

[0028] Structural unit A is also preferably the structural unit represented by the following formula (4).

[0029] [Chemistry 3] (in the above formula (4),) Rc is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Lc is a single bond or a divalent linkage; Rc1, Rc2, and Rc3 are each independently a monovalent hydrocarbon group with 1 to 20 carbon atoms.

[0030] As for Rc, in terms of providing the copolymerization of the monotonous structural unit represented by formula (4), it is preferred to be a hydrogen atom or a methyl group.

[0031] Examples of divalent bonding groups represented by Lc include: alkyldiyl, cycloalkyldiyl, alkenyl, aryl, -OR LA-*, -COOR LB-*, etc. (* indicates a bond on the carbonyl side).

[0032] The alkyl dienyllium is preferably an alkyl dienyllium having 1 to 8 carbon atoms.

[0033] Examples of the cycloalkyl diesters include monocyclic cycloalkyl diesters such as cyclopentanediol and cyclohexanediol, and polycyclic cycloalkyl diesters such as norbornenediol and adamantanediol. Preferably, the cycloalkyl diester has 5 to 12 carbon atoms.

[0034] Examples of the alkenyl group include ethylenediyl, propylenediyl, and butenyldiyl. Preferably, the alkenyl group has 2 to 6 carbon atoms.

[0035] Examples of R LA in -OR LA-* include alkyldiyl, cycloalkyldiyl, and olefinic diyl. Examples of R LB in -COOR LB-* include alkyldiyl, cycloalkyldiyl, olefinic diyl, and aryldiyl. Examples of aryldiyl include phenyldiyl, methylphenyl, and naphthyl. Preferably, the aryldiyl has 6 to 15 carbon atoms.

[0036] In these, Lc is preferably a single bond or -COOR LB-*. As for RLB, it is preferably an alkyl dienylate.

[0037] In Lc, some or all of the hydrogen atoms on the carbon atoms can be substituted by halogen atoms such as fluorine or chlorine atoms, halogenated alkyl groups such as trifluoromethyl, alkoxy groups such as methoxy, cyano, etc.

[0038] As the monovalent hydrocarbon groups with 1 to 20 carbons represented by Rc1, Rc2 and Rc3, the groups exemplified as the monovalent hydrocarbon groups with 1 to 20 carbons represented by RX in the above formula (1) can be the bases.

[0039] Preferably, Rc1 and Rc2 are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, and Rc3 is a monovalent alicyclic or aromatic hydrocarbon group having 6 to 12 carbon atoms. Alternatively, it is also preferred that Rc1, Rc2, and Rc3 are each independently a monovalent chain hydrocarbon group having 1 to 12 carbon atoms.

[0040] The structural unit represented by equation (4) is preferably represented by the following equations (4-1) to (4-18).

[0041] [Chemistry 4]

[0042] [Chemistry 5]

[0043] In equations (4-1) to (4-18), Rc has the same meaning as in equation (4). Preferably, structural unit (II) is represented by equations (4) to (4-3) and (4-10) to (4-12).

[0044] The proportion of structural unit A in the resin (total if multiple structural units A exist) 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 resin. The aforementioned proportion is preferably 80 mol% or less, more preferably 70 mol% or less, and even more preferably 60 mol% or less. By setting the proportion of structural unit A within the aforementioned range, the sensitivity and CDU performance of the radiosensitive linear resin composition can be further improved.

[0045] (Structural Unit B) Structural unit B (hereinafter also referred to as "structural unit B") is a structural unit comprising an organic acid anion moiety and an onium cation moiety containing an aromatic ring structure having a fluorine atom. In other words, structural unit B comprises an organic acid anion moiety and an onium cation moiety, wherein the onium cation moiety contains an aromatic ring structure having a fluorine atom.

[0046] The structural unit B is a monolithic structural unit derived from a structure that decomposes upon exposure to produce acid. Therefore, the resin containing structural unit B functions as a radiosensitive linear acid-generating resin. Examples of onium cations in structural unit B include strontium cations and monium cations.

[0047] The onium cation in the structural unit B is preferably a strontium cation, and the monomer that provides such structural unit B is preferably a structural unit derived from the monomer represented by formula (2) or formula (3).

[0048] [Chemistry 6] , (In equations (2) and (3),) RA and RB are hydrogen atoms, fluorine atoms, methyl groups, or trifluoromethyl groups; RY and RZ are independently hydrogen atoms, fluorine atoms, or fluorinated hydrocarbon groups, with at least one being a fluorine atom or a fluorinated hydrocarbon group; multiple RY and RZ may be the same or different; s is an integer from 1 to 20; R1 to R3 are independently monovalent hydrocarbon groups, and at least one is an aromatic ring with a fluorine atom; R4 to R6 are independently monovalent hydrocarbon groups, and at least one is an aromatic ring with a fluorine atom; Y1 is a single bond or -Y11-C(=O)-O-; Y11 is a divalent hydrocarbon group with 1 to 20 carbon atoms or a divalent hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Y2 can be a single bond, methylene, ethyl, phenyl, fluorinated phenyl, -OY21-, -C(=O)-OY21-, or -C(=O)-NH-Y21-; Y21 can be an alkyldiyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, or a phenyl group, and may contain a carbonyl group, ester bond, ether bond, or hydroxyl group; alkyldiyl groups with 1 to 6 carbon atoms, alkenyl groups with 2 to 6 carbon atoms, and phenyl groups may also be substituted with fluorine atoms.

[0049] In formulas (2) and (3), RY and RZ are independently hydrogen atoms, fluorine atoms, or monovalent fluorinated hydrocarbon groups with 1 to 20 carbon atoms, at least one of which is a fluorine atom or a fluorinated hydrocarbon group. The hydrocarbon group constituting the monovalent fluorinated hydrocarbon group can be any of the following: linear, branched, or cyclic. Specific examples include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tributyl; cycloalkyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups such as vinyl, allyl, propenyl, butenyl, hexenyl, and cyclohexenyl; aryl groups such as phenyl, naphthyl, and thiophene; and aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. As monovalent fluorinated hydrocarbon groups, groups in which some or all of the hydrogen atoms of these hydrocarbon groups are substituted with fluorine-containing groups can be listed. Multiple RY and RZ groups may be the same or different.

[0050] In formula (2), when Y1 is -Y11-C(=O)-O-, the divalent hydrocarbon group with 1 to 20 carbon atoms that can contain heteroatoms, represented by Y11, can be listed below, but is not limited to these. Furthermore, the hydrogen atom contained in the structure shown below can also be substituted by a substituent containing a heteroatom. Such substituents can be listed as: halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), carboxyl groups, hydroxyl groups, thiol groups, amino groups, etc. Among them, Y11 is preferably a divalent aromatic hydrocarbon group containing iodine.

[0051] [Chemistry 7] (In the formula, the dashed lines represent the bonds formed with the oxygen and carbon atoms in formula (2))

[0052] Examples of organic acid anion moieties that provide structural unit B include, but are not limited to, those shown below. Furthermore, the following examples all describe organic acid anion moieties having an iodine-substituted aromatic ring structure; however, for organic acid anion moieties not having an iodine-substituted aromatic ring structure, structures in which the iodine atom in the following formula is substituted by atoms or groups other than the iodine atom, such as hydrogen atoms or other substituents, are preferred.

[0053] [Chemistry 8]

[0054] [Chemistry 9]

[0055] [Chemistry 10]

[0056] [Chemistry 11]

[0057] [Chemistry 12]

[0058] In formulas (2) and (3), R1 to R3 are independently monovalent hydrocarbon groups, at least one of which is an aromatic ring with a fluorine atom; R4 to R6 are independently monovalent hydrocarbon groups, at least one of which is an aromatic ring with a fluorine atom. Furthermore, the term "aromatic ring with a fluorine atom" in this specification refers to a structure in which part or all of the hydrogen atoms in the aromatic ring are substituted with fluorine atoms or fluorinated hydrocarbon groups (preferably perfluorocarbon groups). The monovalent hydrocarbon group can be any of the following: linear, branched, or cyclic. As specific examples, groups identical to those listed as hydrocarbon groups constituting the fluorinated hydrocarbon groups in RY and RZ can be given, preferably aryl groups. Additionally, a portion of the hydrogen atoms in these groups can also be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms. Any two of R1 to R3 can bond to each other and form a ring together with the bonded sulfur atoms; any two of R4 to R6 can bond to each other and form a ring together with the bonded sulfur atoms.

[0059] The onium cation portion in formulas (2) and (3) is preferably represented by the following formula (Q-1).

[0060] [Chemistry 13]

[0061] In formula (Q-1), Ra 1 and Ra 2 each independently represent a substituent. n 1 represents an integer from 0 to 5. When n 1 is 2 or more, multiple Ra 1s can be the same or different. n 2 represents an integer from 0 to 5. When n 2 is 2 or more, multiple Ra 2s can be the same or different. n 3 represents an integer from 1 to 5. When n 3 is 2 or more, multiple Ra 3s can be the same or different. Ra 3 represents a fluorine atom or a group having one or more fluorine atoms. When n 1 is 2 or more, multiple Ra 1s can be linked together to form a ring. When n 2 is 2 or more, multiple Ra 2s can be linked together to form a ring. When n 1 is 1 or more and n 2 is 1 or more, Ra 1 and Ra 2 can be linked together to form a ring (i.e., a heterocycle containing a sulfur atom).

[0062] The substituents represented by Ra 1 and Ra 2 are preferably alkyl, cycloalkyl, alkoxy, cycloalkyloxy, alkoxycarbonyl, alkylsulfonyl, cycloalkylsulfonyl, hydroxyl, halogen atom, or halogenated hydrocarbon group.

[0063] The alkyl groups of Ra 1 and Ra 2 can be straight-chain or branched-chain. Preferably, the alkyl group is an alkyl group having 1 to 10 carbon atoms, for example, the same group as those listed as hydrocarbon groups constituting the fluorinated hydrocarbon groups in RY and RZ. Among these, methyl, ethyl, n-butyl, and tributyl are particularly preferred.

[0064] As cycloalkyl groups of Ra 1 and Ra 2, examples include monocyclic or polycyclic cycloalkyl groups (preferably cycloalkyl groups with 3 to 20 carbon atoms), such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclododecyl, cyclopentenyl, cyclohexenyl, and cyclooctadienyl. Among these, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl are particularly preferred.

[0065] The alkyl moiety of the alkoxy group in Ra 1 and Ra 2 can be, for example, the groups previously listed as alkyl groups in Ra 1 and Ra 2. Preferably, the alkoxy group is methoxy, ethoxy, n-propoxy, or n-butoxy.

[0066] The cycloalkyl moiety of Ra 1 and Ra 2 can be, for example, the groups previously listed as cycloalkyl groups of Ra 1 and Ra 2. Cyclopentyloxy and cyclohexyloxy are particularly preferred as the cycloalkyloxy group.

[0067] The alkoxy moiety of the alkoxy carbonyl group in Ra 1 and Ra 2 can be, for example, the groups previously listed as alkoxy groups in Ra 1 and Ra 2. Preferably, the alkoxy carbonyl group is methoxy carbonyl, ethoxy carbonyl, or n-butoxy carbonyl.

[0068] The alkyl portion of the alkyl sulfonyl group in Ra 1 and Ra 2 can be, for example, the groups previously listed as alkyl groups in Ra 1 and Ra 2. Similarly, the cycloalkyl portion of the cycloalkyl sulfonyl group in Ra 1 and Ra 2 can be, for example, the groups previously listed as cycloalkyl groups in Ra 1 and Ra 2. Preferably, these alkyl sulfonyl or cycloalkyl sulfonyl groups are methanesulfonyl, ethanesulfonyl, n-propanesulfonyl, n-butanesulfonyl, cyclopentanesulfonyl, and cyclohexanesulfonyl.

[0069] Each group of Ra 1 and Ra 2 may also have substituents. Examples of such substituents include: halogen atoms such as fluorine atoms (preferably fluorine atoms), hydroxyl groups, carboxyl groups, cyano groups, nitro groups, alkoxy groups, cycloalkyloxy groups, alkoxyalkyl groups, cycloalkyloxyalkyl groups, alkoxycarbonyl groups, cycloalkyloxycarbonyl groups, alkoxycarbonyloxy groups, and cycloalkyloxycarbonyloxy groups.

[0070] Halogen atoms that can be used as Ra 1 and Ra 2 include: fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms and iodine atoms being preferred.

[0071] The halogenated hydrocarbon groups of Ra 1 and Ra 2 are preferably alkyl halides. Examples of alkyl groups and halogen atoms constituting alkyl halides are the same as described above. Among them, fluorinated alkyl groups are preferred, and CF 3 is even more preferred.

[0072] As described, Ra 1 and Ra 2 can also be linked together to form a ring (i.e., a heterocycle containing sulfur atoms). In this case, it is preferable that Ra 1 and Ra 2 are linked together to form a single bond or a divalent linker. Examples of divalent linkers include: -COO-, -OCO-, -CO-, -O-, -S-, -SO-, -SO 2-, alkylene, cycloalkylene, alkenylene, or combinations of two or more of these, preferably with a total carbon number of 20 or less. When Ra 1 and Ra 2 are linked together to form a ring, Ra 1 and Ra 2 are preferably linked together to form -COO-, -OCO-, -CO-, -O-, -S-, -SO-, -SO 2-, or a single bond. More preferably, -O-, -S-, or a single bond are formed, and especially preferably, a single bond is formed. Furthermore, when n1 is 2 or more, multiple Ra1s can be linked together to form a ring, and when n2 is 2 or more, multiple Ra2s can be linked together to form a ring. As an example, one can illustrate the state in which two Ra1s are linked together and together with the bonded benzene rings to form a naphthalene ring.

[0073] Ra 3 is a fluorine atom or a group having one or more fluorine atoms. Examples of groups having fluorine atoms include alkyl, cycloalkyl, alkoxy, cycloalkyloxy, alkoxycarbonyl, and alkylsulfonyl groups formed by fluorine atom substitution in Ra 1 and Ra 2. Fluorinated alkyl groups are preferred examples, and more preferably CF 3, C 2F 5, C 3F 7, C 4F 9, C 5F 11, C 6F 13, C 7F 15, C 8F 17, CH 2CF 3, CH 2CH 2CF 3, CH 2C 2F 5, CH 2CH 2C 2F 5, CH 2C 3F 7, CH 2CH 2C 3F 7, CH 2C 4F 9, and CH 2CH 2C 4F 9, with CF 3 being particularly preferred.

[0074] Ra 3 is preferably a fluorine atom or CF 3, and more preferably a fluorine atom.

[0075] n is preferably 1~3, and even better is 1 or 2.

[0076] The ratio of (n1+n2+n3) is preferably 1~15, more preferably 1~9, further preferably 2~6, and especially preferably 3~6. When (n1+n2+n3) is 1, it is preferable that n3=1 and Ra3 is a fluorine atom or CF3. When (n1+n2+n3) is 2, it is preferable that n1=n3=1 and Ra1 and Ra3 are each independently a combination of fluorine atoms or CF3, and that n3=2 and Ra3 is a combination of fluorine atoms or CF3. When (n1+n2+n3) is 3, it is preferable that n1=n2=n3=1 and Ra1~Ra3 are each independently a combination of fluorine atoms or CF3. When (n1+n2+n3) is 4, it is preferable that n1=n3=2 and Ra1 and Ra3 are each independently a combination of fluorine atoms or CF3. When (n1+n2+n3) is 5, it is preferable that n1=n2=1 and n3=3 and Ra1~Ra3 are each independently a combination of fluorine atoms or CF3, n1=n2=2 and n3=1 and Ra1~Ra3 are each independently a combination of fluorine atoms or CF3, and n3=5 and Ra3 are each independently a combination of fluorine atoms or CF3. When (n1+n2+n3) is 6, it is preferable that n1=n2=n3=2 and Ra1~Ra3 are each independently a combination of fluorine atoms or CF3.

[0077] As a specific example of the onium cation portion represented by the formula (Q-1) described therein, the onium cations in the onium salts described later can be cited.

[0078] The onium cation in structural unit B is preferably a diaryl ionium cation having one or more fluorine atoms.

[0079] Specific examples of diaryl monazine cations having one or more fluorine atoms include the following. Furthermore, the following examples all contain monazine cation moieties with aromatic ring structures having fluorine atoms, and structures in which the fluorine atoms are substituted with fluorinated hydrocarbon groups such as trifluoromethyl are also preferred.

[0080] [Chemistry 14]

[0081] The proportion of structural unit B in the resin (total if multiple structural units B exist) relative to all structural units constituting the resin is preferably 2 mol% or more, more preferably 3 mol% or more, further preferably 4 mol% or more, and particularly preferably 5 mol% or more. Additionally, it is preferably 30 mol% or less, more preferably 25 mol% or less, further preferably 20 mol% or less, and particularly preferably 15 mol% or less. By setting this proportion within the aforementioned range, its function as a resin for generating radiosensitive linear acids can be fully realized.

[0082] (Structural Unit D) Structural unit D is a structural unit having a phenolic hydroxyl group, and having a phenolic hydroxyl group and an alkyl group on the same aromatic ring. In this aromatic ring, an alkyl group is bonded to the carbon atom adjacent to the carbon atom bonded to the phenolic hydroxyl group. In other words, structural unit D is a structural unit having a phenolic hydroxyl group, and an alkyl group is further bonded to the aromatic ring bonded to the phenolic hydroxyl group, with the carbon atom bonded to the phenolic hydroxyl group directly connected to the carbon atom bonded to the alkyl group. In this invention, phenolic hydroxyl groups generated by deprotection using acids produced by exposure are also included as phenolic hydroxyl groups in structural unit D. The reason for achieving the effects of this invention by including structural unit D in the resin is uncertain, but as a possibility, the following is considered: It is believed that the phenolic hydroxyl group in the resin interacts with the onium cation portion of the radiosensitive linear acid-generating resin or the onium cation in the onium salt, worsening development defects. On the other hand, it is speculated that the presence of an alkyl group near the phenolic hydroxyl group in the resin weakens the interaction due to steric hindrance, resulting in no improvement in development defects. Furthermore, when using KrF excimer laser light, EUV, electron beam, or the like as the radiation irradiated in the exposure step of the resist patterning method, structural unit D helps to improve etch resistance and increase the difference in developer solubility (solution contrast) between the exposed and unexposed areas. It is particularly suitable for patterning using exposure with radiation of wavelengths below 50 nm, such as electron beams or EUV. Structural unit D is preferably represented by the following formula (D).

[0083] [Chemistry 15] (In the aforementioned formula (D), Rα is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; L CA represents a single bond, -COO-*, or -O-; * represents a bond on the aromatic ring side; R 101 is a hydrogen atom or a protecting group that has been deprotected by an acid to become a hydrogen atom; if multiple R 101s exist, they may be the same or different from each other; at least one R 101 is a hydrogen atom; R 102 is cyano, nitro, alkyl, fluorinated alkyl, alkoxycarbonyloxy, acetyl, or acetyloxy; wherein at least one R 102 is an alkyl group; n d3 is an integer from 0 to 2, m d3 is an integer from 1 to 8, and m 4 is an integer from 1 to 8; where 1 ≤ m d3 + m 4 ≤ 2n d3 + 5). In formula (D), R102 is bonded to the carbon atom adjacent to the carbon atom bonded to the phenolic hydroxyl group, and R102 is an alkyl group.

[0084] As for Rα, from the viewpoint of providing the copolymerization of the monolithic structural unit D, it is preferably a hydrogen atom or a methyl group.

[0085] For L CA, a single bond or -COO-* is preferred.

[0086] As the protecting group represented by R 101 that is deprotected under the action of acid, examples include the groups represented by formulas (AL-1) to (AL-3) below.

[0087] [Chemistry 16]

[0088] In formulas (AL-1) and (AL-2), RM1 and RM2 are monovalent hydrocarbon groups, which may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The monovalent hydrocarbon group can be linear, branched, or cyclic, preferably an alkyl group with 1 to 40 carbon atoms, and more preferably an alkyl group with 1 to 20 carbon atoms. In formula (AL-1), a is an integer from 0 to 10, preferably an integer from 1 to 5. In formulas (AL-1) to (AL-3), * represents a bond with other parts.

[0089] In formula (AL-2), RM3 and RM4 are each independently a hydrogen atom or a monovalent hydrocarbon group, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The monovalent hydrocarbon group can be linear, branched, or cyclic, preferably an alkyl group with 1 to 20 carbon atoms. Furthermore, any two of RM2, RM3, and RM4 can be bonded to each other and form a ring with 3 to 20 carbon atoms together with the bonded carbon atoms or carbon atoms and oxygen atoms. The ring is preferably a ring with 4 to 16 carbon atoms.

[0090] In formula (AL-3), RM5, RM6, and RM7 are each independently a monovalent hydrocarbon group, which may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The monovalent hydrocarbon group can be linear, branched, or cyclic, preferably an alkyl group with 1 to 20 carbon atoms. Furthermore, any two of RM5, RM6, and RM7 can be bonded to each other and together with the bonded carbon atoms to form a ring with 3 to 20 carbon atoms. The ring is preferably a ring with 5 to 16 carbon atoms, and particularly preferably an alicyclic ring.

[0091] Among these, the protecting group that is deprotected under the action of acid is preferably the group represented by the formula (AL-3).

[0092] Examples of alkyl groups in R 102 include straight-chain or branched alkyl groups with 1 to 8 carbon atoms, such as methyl, ethyl, and propyl. Examples of fluorinated alkyl groups include straight-chain or branched fluorinated alkyl groups with 1 to 8 carbon atoms, such as trifluoromethyl and pentafluoroethyl. Examples of alkoxycarbonyl groups include chain-like or alicyclic alkoxycarbonyl groups with 2 to 16 carbon atoms, such as methoxycarbonyl, butoxycarbonyl, and adamantylmethyloxycarbonyl. Examples of acetyl groups include aliphatic or aromatic acetyl groups with 2 to 12 carbon atoms, such as acetyl, propoxy, benzoyl, and propoxy. Examples of acetyloxy groups include aliphatic or aromatic acetyloxy groups with 2 to 12 carbon atoms, such as acetyloxy, propoxy, benzoyloxy, and propoxy.

[0093] As stated in n d3, it is more preferably 0 or 1, and even more preferably 0.

[0094] The m d3 is preferably an integer from 1 to 3, and more preferably 1 or 2.

[0095] The value of m4 is preferably an integer from 1 to 3, and more preferably an integer from 1 to 2.

[0096] In the aromatic ring of structural unit D, an alkyl group may be bonded to only one of the carbon atoms adjacent to the carbon atom bonded to the phenolic hydroxyl group, or an alkyl group may be bonded to both carbon atoms. In the case where an alkyl group is bonded to only one of the carbon atoms adjacent to the carbon atom bonded to the phenolic hydroxyl group, the other carbon atom may be bonded to LCA, to the main chain of the resin, or be unsubstituted (i.e., bonded to a hydrogen atom), or bonded to a substituent other than an alkyl group.

[0097] In the aromatic ring of the structural unit D, the alkyl group bonded to the carbon atom adjacent to the carbon atom bonded to the phenolic hydroxyl group is preferably an alkyl group with 1 to 4 carbon atoms, more preferably a straight-chain or branched alkyl group with 1 to 3 carbon atoms, and even more preferably methyl, ethyl, or isopropyl, and especially preferably methyl.

[0098] Examples of monotonous entities providing this structural unit D include: 3-alkyl-4-hydroxystyrene, 3,5-dialkyl-4-hydroxystyrene, 3-alkyl-4-hydroxy-5-iodostyrene, 3,4-dihydroxy-5-alkylstyrene, 4-alkyl-3-hydroxystyrene, 2,4-dialkyl-3-hydroxystyrene, 3-alkyl-2-hydroxystyrene, 3-alkyl-4-hydroxyphenyl ester (meth)acrylate, 3,5-dialkyl-4-hydroxyphenyl ester (meth)acrylate, 3-alkyl-4-hydroxy-5-iodophenyl ester (meth)acrylate, 3,4-dihydroxy-5-alkylphenyl ester (meth)acrylate, 4-alkyl-3-hydroxyphenyl ester (meth)acrylate, 2,4-dialkyl-3-hydroxyphenyl ester (meth)acrylate, 3-alkyl-2-hydroxyphenyl ester (meth)acrylate, etc. Preferably, the monomers are 3-alkyl-4-hydroxystyrene, 3,5-dialkyl-4-hydroxystyrene, 3-alkyl-4-hydroxyphenyl ester (meth)acrylate, and 3,5-dialkyl-4-hydroxyphenyl ester (meth)acrylate. When these monomers have two or more alkyl groups, the alkyl groups may be the same or different.

[0099] The structural unit D is preferably a structural unit represented by the following formulas (D-1) to (D-10) (hereinafter also referred to as "structural unit (D-1) to structural unit (D-10)").

[0100] [Chemistry 17]

[0101] In equations (D-1) to (D-10), Rα is the same as in equation (D).

[0102] Among these, the structural units (D-1) to (D-2), (D-5), and (D-8) to (D-10) are preferred.

[0103] The content ratio of structural unit D (total if multiple structural units D exist) is preferably 5 mol% or more, more preferably 8 mol% or more, further preferably 10 mol% or more, and particularly preferably 15 mol% or more, relative to all structural units constituting the resin. The content ratio is preferably 60 mol% or less, more preferably 50 mol% or less, further preferably 40 mol% or less, and particularly preferably 35 mol% or less. By setting the content ratio of structural unit D within the aforementioned range, the radiosensitive linear resin composition can achieve further improvements in sensitivity, CDU performance, and resolution.

[0104] Furthermore, the proportion of structural unit D (total when there are multiple structural units D) is preferably 15 mol% or more, more preferably 30 mol% or more, more preferably 50 mol% or more, and especially preferably 65 mol% or more, relative to all structural units having phenolic hydroxyl groups.

[0105] In the case of polymerizing monomers of 3-alkyl-hydroxystyrene and the like with phenolic hydroxyl groups, it is preferable to polymerize under the condition that the phenolic hydroxyl groups are protected by protecting groups such as base dissociation groups, and then perform hydrolysis to deprotect them, thereby obtaining structural unit D.

[0106] (Structural Unit E) Structural unit E is a structural unit comprising at least one selected from the group consisting of lactone structures, cyclic carbonate structures, and sulfonyl lactone structures. By having structural unit E, the solubility of the base resin in the developer can be adjusted, resulting in improved lithography properties such as resolution in the radiosensitive linear resin composition. Furthermore, the adhesion between the resist pattern formed from the base resin and the substrate can be improved.

[0107] When structural unit E is included, the content ratio of structural unit E relative to all structural units constituting the base resin is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more. The content ratio is preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 40 mol% or less. By setting the content ratio of structural unit E within the aforementioned range, the radiosensitive linear resin composition can further improve lithography properties such as resolution and the adhesion between the formed resist pattern and the substrate.

[0108] The base resin of this invention may contain structural units other than structural unit A, structural unit B, structural unit D, and structural unit E. Examples of such other structural units include: structural units having phenolic hydroxyl groups, such as hydroxystyrene or hydroxyphenyl methacrylate (except structural unit D); structural units having aliphatic hydrocarbon groups, such as alkyl methacrylate (except structural unit A); structural units having alicyclic hydrocarbon groups, such as cycloalkyl methacrylate or adamantyl methacrylate (except structural unit A); and structural units having aromatic hydrocarbon groups, such as styrene, phenyl methacrylate, and iodostyrene.

[0109] The base resin of the present invention preferably contains an iodine-substituted aromatic ring structure. The iodine-substituted aromatic ring structure of the base resin may be included in any one of structural units A to E, or in structural units other than structural units A to E. More preferably, it is included in any one or more of structural units A, B, and D. As an example of structural units other than structural units A to E containing an iodine-substituted aromatic ring structure, structural units derived from iodostyrene can be cited. The proportion of the iodine-substituted aromatic ring structure relative to all structural units constituting the base resin is preferably 1 mol% or more, more preferably 2 mol% or more, and even more preferably 3 mol% or more. The aforementioned proportion is preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less. By setting the proportion of the iodine-substituted aromatic ring structure within the aforementioned range, the lithography properties such as CDU performance of the radiosensitive linear resin composition can be further improved.

[0110] (Methods for synthesizing resins) The base resin can be synthesized by using known free radical polymerization initiators, for example, by polymerizing monomers that provide each structural unit in a suitable solvent.

[0111] The molecular weight of the resin used as the base resin is not particularly limited, but the equivalent weight average molecular weight (Mw) of the 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, it 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 resin is within the aforementioned range, the obtained resist film exhibits good heat resistance and developability.

[0112] The ratio (Mw / Mn) of the resin as the base resin to the equivalent number average molecular weight (Mn) of the polystyrene obtained by GPC is generally 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.

[0113] The Mw and Mn values ​​of the resin in this specification are values ​​determined by gel permeation chromatography (GPC) under the following conditions. 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

[0114] The resin content, relative to the total solids content of the radiosensitive linear resin composition, is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more.

[0115] <Other Resins> The radiosensitive linear resin composition of this embodiment may also include a resin with a fluorine atom mass content greater than that of the base resin (hereinafter also referred to as "high fluorine content resin") as another resin. 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 allowing the surface state of the resist film to be controlled to a desired state.

[0116] As a high-fluorine content resin, it is preferred to have, for example, one or more of the structural units A to E in the base resin as needed, and to have the structural unit represented by the following formula (f0) (hereinafter also referred to as "structural unit F").

[0117] [Chemistry 18]

[0118] In formula (f0), R13 is a hydrogen atom, a methyl group, or a trifluoromethyl group. GL is a single bond, an oxygen atom, a 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.

[0119] As for R 13, from the viewpoint of providing the copolymerization of the monolithic structural unit F, it is preferably hydrogen atoms and methyl groups, and more preferably methyl groups.

[0120] As for the GL, from the viewpoint of providing the copolymerization of the monolithic structural unit F, it is preferred to have a single bond and -COO-, more preferably -COO-.

[0121] As the monovalent fluorinated chain hydrocarbon group with 1 to 20 carbon atoms represented by R 14, examples include those in which some or all of the hydrogen atoms of a straight-chain or branched alkyl group with 1 to 20 carbon atoms are replaced by fluorine atoms.

[0122] As the monovalent fluorinated alicyclic hydrocarbon group with 3 to 20 carbon atoms represented by R 14, examples include monocyclic or polycyclic hydrocarbon groups with 3 to 20 carbon atoms in which some or all of the hydrogen atoms are replaced by fluorine atoms.

[0123] As R 14, 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-hexafluoropropyl, 5,5,5-trifluoro-1,1-diethylpentyl and 1,1,1,2,2,3,3-heptafluoro-6-methylheptane-4-yl.

[0124] When the high-fluorine content resin has structural unit F, the content ratio of structural unit F relative to all structural units constituting the high-fluorine content resin is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more. Furthermore, the content ratio is preferably 100 mol% or less, more preferably 95 mol% or less, and even more preferably 90 mol% or less. By setting the content ratio of structural unit F within the aforementioned range, the mass content of fluorine atoms in the high-fluorine content resin can be adjusted more appropriately, further promoting its biased presence on the surface of the resist film.

[0125] In addition to structural unit F, high-fluorine-content resins may also have other structural units. Examples of other structural units include: structural unit G having an alcoholic hydroxyl group and a fluorinated hydrocarbon group bonded to the carbon atom bonded to the alcoholic hydroxyl group; and structural unit H comprising at least one selected from the group consisting of iodine and bromine atoms. Structural unit H is more preferably an aromatic ring structure comprising an iodine atom.

[0126] When the high-fluorine content resin has structural unit G, the content ratio of structural unit G relative to all structural units constituting the high-fluorine content resin is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more. The content ratio is preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. When the high-fluorine content resin has structural unit H, the content ratio of structural unit H relative to all structural units constituting the high-fluorine content resin is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more. The content ratio is preferably 40 mol% or less, more preferably 30 mol% or less, and even more preferably 20 mol% or less. By setting the content ratios of structural units G and H within the aforementioned ranges, the surface of the resist film can be controlled to a desired state.

[0127] 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 20,000 or less, and particularly preferably 15,000 or less.

[0128] The Mw / Mn ratio of a high-fluorine content resin is typically 1 or more, more preferably 1.1 or more. The Mw / Mn ratio is typically 5 or less, more preferably 3 or less, more preferably 2.5 or less, and even more preferably 2.2 or less.

[0129] The content of the high-fluorine resin is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, relative to 100 parts by mass of the base resin (in the case of including the radiosensitive linear acid generating resin and the resin). The content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less. By setting the content 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, resulting in suppression of dissolution at the top of the pattern during development and improved pattern rectangularity. The radiosensitive linear resin composition may also contain one or more high-fluorine resins.

[0130] (Synthesis method of high fluorine content resin) High-fluorine-content resins can be synthesized using the same method as the synthesis of the base resin.

[0131] <O-Salt> Onium salts comprise an organic acid anion moiety and an onium cation moiety, and are components that generate acid through exposure. By having at least a portion of the onium cation moiety in the onium salt contain an aromatic ring structure with fluorine atoms, high sensitivity can be achieved through increased acid generation efficiency, and CDU performance can be enhanced through acid diffusion control.

[0132] The form in which the onium salt is present in the radiosensitive linear resin composition is not particularly limited, but the onium salt is preferably selected from at least one of the group consisting of radiosensitive linear acid generating resin, radiosensitive linear acid generating agent, and acid diffusion control agent. The radiosensitive linear acid generating resin comprises a structural unit having an organic acid anion portion and an onium cation portion; the radiosensitive linear acid generating agent comprises the organic acid anion portion and the onium cation portion; and the acid diffusion control agent comprises the organic acid anion portion and the onium cation portion. The acid, by irradiation with radiation, produces an acid with a higher pKa compared to the acid produced by the radiosensitive linear acid generating agent. The differences in these functions will be explained below.

[0133] The acid generated by exposing an onium salt to light is considered to perform two functions in the radiosensitive linear resin composition, depending on the strength of the acid. The first function can be listed as follows: the acid generated by exposure causes the acid dissociation groups in the resin to dissociate and generate carboxyl groups, etc. An onium salt having this first function is called a radiosensitive linear acid generator. The second function can be listed as follows: under the patterning conditions of the radiosensitive linear resin composition, it substantially prevents the dissociation of the acid dissociation groups in the resin, and suppresses the diffusion of the acid generated by the radiosensitive linear acid generator in the unexposed area through salt exchange. An onium salt having this second function is called an acid diffusion control agent. The acid generated by the acid diffusion control agent can be considered a relatively weak acid (acid with a high pKa) compared to the acid generated by the radiosensitive linear acid generator. Whether an onium salt functions as a radiosensitive linear acid generator or an acid diffusion control agent depends on the energy required to dissociate the acid dissociation groups in the resin and the acidity of the onium salt. The form in which a radiosensitive linear acid generator is contained in a radiosensitive linear resin composition can be an onium salt structure existing alone as a compound (free from the polymer), or an onium salt structure incorporated as part of the polymer, or both. The form in which the onium salt structure is incorporated as part of the polymer is specifically referred to as a radiosensitive linear acid generator resin.

[0134] By including the radiosensitive linear resin composition containing the radiosensitive linear acid generator or the radiosensitive linear acid generating resin, the polarity of the resin in the exposure section increases. The resin in the exposure section is soluble in the developer when developed in an alkaline aqueous solution, but is sparingly soluble in the developer when developed in an organic solvent.

[0135] Furthermore, by including the acid diffusion control agent in the radiosensitive linear resin composition, the diffusion of acid in the unexposed area can be suppressed, and a resist pattern with better pattern developability and CDU performance can be formed.

[0136] In this radiosensitive linear resin composition, the onium cation portion of at least one of the group consisting of the radiosensitive linear acid generating resin, the radiosensitive linear acid generating agent, and the acid diffusion control agent may contain the aromatic ring structure having fluorine atoms.

[0137] Even if the onium salt is in any containing form, the organic acid anion portion is preferably at least one selected from the group consisting of sulfonate anions, carboxylate anions, and sulfadiazine anions. Furthermore, the onium cation is preferably at least one selected from the group consisting of strontium cations and monium cations. By combining onium salts with these structures, the aforementioned functions can be performed efficiently.

[0138] Examples of acids produced by exposure include sulfonic acids, carboxylic acids, and sulfadienes, which are produced by exposure in accordance with the organic acid anions mentioned above.

[0139] For example, examples of onium salts that provide sulfonic acid through exposure include: (1) A compound having one or more fluorine atoms or fluorinated hydrocarbon groups bonded to a carbon atom adjacent to a sulfonate anion. (2) A compound in which neither a fluorine atom nor a fluorinated hydrocarbon group is bonded to a carbon atom adjacent to a sulfonate anion.

[0140] Examples of onium salts that provide carboxylic acids through exposure include: (3) Compounds in which one or more fluorine atoms or fluorinated hydrocarbon groups are bonded to a carbon atom adjacent to a carboxylate anion. (4) A compound in which neither a fluorine atom nor a fluorinated hydrocarbon group is bonded to a carbon atom adjacent to a carboxylate anion.

[0141] Of these, the one that corresponds to (1) is preferred as the radiosensitive linear acid generator or the radiosensitive linear acid generating resin. The one that corresponds to (2), (3) or (4) is preferred as the acid diffusion control agent, and the one that corresponds to (2) or (4) is particularly preferred.

[0142] <Radiosensitive linear acid generator> The radiosensitive linear resin composition preferably further includes a radiosensitive linear acid generator, which, upon irradiation (exposure) with radiation, produces an acid with a lower pKa compared to the acid produced by the acid diffusion control agent. The radiosensitive linear resin composition contains the radiosensitive linear acid generator, thereby causing the acid-dissociating groups of the resin to dissociate upon exposure, producing carboxyl groups, etc. As a result, the polarity of the resin in the exposed section increases; the resin in the exposed section is soluble in the developer when developed in an alkaline aqueous solution, but sparingly soluble in the developer when developed with an organic solvent.

[0143] The radiosensitive linear acid generator preferably comprises an organic acid anion moiety and an onium cation moiety. The organic acid anion moiety is preferably at least one selected from the group consisting of sulfonate anions and sulfadiazine anions. Examples of acids generated by exposure, corresponding to the organic acid anion moiety, include sulfonic acids and sulfadiazine. The organic acid anion moiety preferably comprises an iodine-substituted aromatic ring structure.

[0144] Among them, as a radiosensitive linear acid generator that provides sulfonic acid through exposure, a compound having one or more fluorine atoms or fluorinated hydrocarbon groups bonded to the carbon atom adjacent to the sulfonate anion is preferred.

[0145] The radiosensitive linear acid generator is preferably represented by the following formula (A-1) or the following formula (A-2).

[0146] [Chemistry 15]

[0147] In formulas (A-1) and (A-2), L1 is a single bond, an ether bond, or an ester bond, or an alkyl group having 1 to 6 carbon atoms that may contain an ether bond or an ester bond. The alkyl group may be linear, branched, or cyclic.

[0148] R1 is a hydroxyl, carboxyl, fluorine, chlorine, bromine, or amino group; or an alkyl group of 1 to 20 carbons that may contain a fluorine, chlorine, bromine, hydroxyl, amino, or an alkoxy group of 1 to 10 carbons; an alkoxy group of 1 to 20 carbons; an alkoxycarbonyl group of 2 to 10 carbons; an acetoxy group of 2 to 20 carbons; or an alkylsulfonyloxy group of 1 to 20 carbons; or -NR 8-C(=O)-R 9 or -NR 8-C(=O)-OR 9, where R8 is a hydrogen atom; or an alkyl group of 1 to 6 carbons that may contain a halogen atom, a hydroxyl group, an alkoxy group of 1 to 6 carbons, an acetyl group of 2 to 6 carbons; or an alkyl group of 2 to 6 carbons that may contain an alkoxy group of 2 to 6 carbons. 9 is an alkyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a cellulose group having 2 to 6 carbon atoms, or a cellulose-oxy group having 2 to 6 carbon atoms. The alkyl group, alkoxy group, alkoxycarbonyl group, cellulose-oxy group, cellulose group, and alkenyl group may be linear, branched, or cyclic.

[0149] Among these, R1 is preferably a hydroxyl group, -NR8-C(=O)-R9, a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, etc.

[0150] R2 is a single bond or a divalent linker with 1 to 20 carbon atoms when p is 1, and a trivalent or tetravalent linker with 1 to 20 carbon atoms when p is 2 or 3. The linker may contain oxygen, sulfur or nitrogen atoms.

[0151] Rf1 through Rf4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. Additionally, Rf1 and Rf2 can combine to form a carbonyl group. Preferably, both Rf3 and Rf4 are fluorine atoms.

[0152] R3, R4, R5, R6, and R7 are each independently a monovalent hydrocarbon group with 1 to 20 carbon atoms, which may contain heteroatoms. Furthermore, any two of R3, R4, and R5 may bond to each other and form a ring together with the bonded sulfur atoms. The monovalent hydrocarbon group may be linear, branched, or cyclic; specific examples include alkyl groups with 1 to 12 carbon atoms, alkenyl groups with 2 to 12 carbon atoms, alkynyl groups with 2 to 12 carbon atoms, aryl groups with 6 to 20 carbon atoms, and aralkyl groups with 7 to 12 carbon atoms. Additionally, some or all of the hydrogen atoms in these groups may be substituted with hydroxyl, carboxyl, halogen, cyano, amide, nitro, mercapto, sulopentalide, urethane, or strontium-containing groups, and some of the carbon atoms in these groups may be substituted with ether, ester, carbonyl, carbonate, or sulfonate bonds.

[0153] p is an integer satisfying 1 ≤ p ≤ 3. q and r are integers satisfying 0 ≤ q ≤ 5, 0 ≤ r ≤ 3, and 0 ≤ q + r ≤ 5. q is preferably an integer satisfying 1 ≤ q ≤ 3, more preferably 2 or 3. r is preferably an integer satisfying 0 ≤ r ≤ 2.

[0154] As the anionic portion of the radiosensitive linear acid generator represented by formulas (A-1) and (A-2), examples can be listed below, but are not limited to these. Furthermore, as the anionic portion of the organic acid anion that does not have an iodine-substituted aromatic ring structure, a structure in which the iodine atom in the following formula is substituted by an atom or group other than the iodine atom, such as a hydrogen atom or other substituent, is preferred.

[0155] [Chemistry 20]

[0156] [Chemistry 21]

[0157] In addition, examples of the organic acid anion portion of the radiosensitive linear acid generator represented by formulas (A-1) and (A-2) are given below, as well as examples of organic acid anion portions that are not equivalent to those of formulas (A-1) and (A-2).

[0158] [Chemistry 22]

[0159] [Chemistry 23]

[0160] [Chemistry 24]

[0161] The onium cation portion in the radiosensitive linear acid generator represented by formula (A-1) can preferably adopt the structure exemplified by the onium cation portion in structural unit B that can be included in the resin. Preferably, it is an onium cation containing an aromatic ring structure having fluorine atoms; more preferably, it is an onium cation represented by formula (Q-1); even more preferably, it is a strontium cation containing two or more aromatic ring structures having fluorine atoms; and most preferably, it is a strontium cation containing three aromatic ring structures having fluorine atoms.

[0162] These radiosensitive linear acid generators can be used alone or in combination of two or more. The lower limit of the content of the radiosensitive linear acid generator relative to 100 parts by weight of the base resin is preferably 0.5 parts by weight, more preferably 1 part by weight, further preferably 1.5 parts by weight, and particularly preferably 2 parts by weight. Furthermore, the upper limit of the content relative to 100 parts by weight of the resin is preferably 20 parts by weight or less, more preferably 18 parts by weight or less, further preferably 15 parts by weight or less, and particularly preferably 12 parts by weight or less. This allows for excellent sensitivity or CDU performance when forming resist patterns.

[0163] <Acid diffusion control agent> An acid diffusion control agent comprises an organic acid anion moiety and an onium cation moiety, which, upon irradiation with radiation, produces an acid with a higher pKa compared to an acid produced by a radiosensitive linear acid generator. Carboxylic acids can be cited as examples of this organic acid anion moiety. The organic acid anion moiety preferably comprises an iodine-substituted aromatic ring structure. The acid diffusion control agent is preferably represented by the following formula (S-1) or the following formula (S-2).

[0164] [Chemistry 25]

[0165] In formulas (S-1) and (S-2), R1 is a hydrogen atom, a hydroxyl group, a fluorine atom, a chlorine atom, an amino group, a nitro group, or a cyano group, or an alkyl group with 1 to 6 carbon atoms that can be substituted with a halogen atom, an alkoxy group with 1 to 6 carbon atoms, an acetoxy group with 2 to 6 carbon atoms, or an alkyl sulfonoxy group with 1 to 4 carbon atoms, or -NR1A-C(=O)-R1B or -NR1A-C(=O)-OR1B. R1A is a hydrogen atom or an alkyl group with 1 to 6 carbon atoms, and R1B is an alkyl group with 1 to 6 carbon atoms or an alkenyl group with 2 to 8 carbon atoms.

[0166] The alkyl group having 1 to 6 carbon atoms can be linear, branched, or cyclic. Specific examples include: methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, dibutyl, tributyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, etc. Furthermore, the alkyl moiety of alkoxy groups having 1 to 6 carbon atoms, acetoxy groups having 2 to 7 carbon atoms, and alkoxycarbonyl groups having 2 to 7 carbon atoms can be the same as the specific examples of the alkyl group. Similarly, the alkyl moiety of alkylsulfonoxy groups having 1 to 4 carbon atoms can be examples of alkyl groups having 1 to 4 carbon atoms. The alkenyl group having 2 to 8 carbon atoms can be linear, branched, or cyclic. Specific examples include: vinyl, 1-propenyl, 2-propenyl, etc. Among these, R1 is preferably a fluorine atom, a chlorine atom, a hydroxyl group, an amino group, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, an aceoxy group having 2 to 4 carbon atoms, -NR1A-C(=O)-R1B, -NR1A-C(=O)-OR1B, etc.

[0167] R3, R4, R5, R6, and R7 are each independently a monovalent hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms. When the onium cation moiety of the acid diffusion control agent has a fluorine atom, at least one of R3, R4, and R5 contains more than one fluorine atom, and at least one of R6 and R7 contains more than one fluorine atom. Furthermore, any two of R3, R4, and R5 may be bonded to each other and form a ring together with the bonded sulfur atoms. The monovalent hydrocarbon group can be linear, branched, or cyclic; specific examples include alkyl groups with 1 to 12 carbon atoms, alkenyl groups with 2 to 12 carbon atoms, alkynyl groups with 2 to 12 carbon atoms, aryl groups with 6 to 20 carbon atoms, and aralkyl groups with 7 to 12 carbon atoms. In addition, some or all of the hydrogen atoms of these groups may be substituted with hydroxyl, carboxyl, halogen, cyano, amide, nitro, mercapto, sulopentalide, urethane or strontium salt-containing groups, and some of the carbon atoms of these groups may be substituted with ether, ester, carbonyl, carbonate or sulfonate bonds.

[0168] L1 is a single bond or a divalent linker with 1 to 20 carbon atoms, and may include ether bonds, carbonyl groups, ester bonds, amide bonds, sulopentalide rings, endamide rings, carbonate bonds, halogen atoms, hydroxyl groups, or carboxyl groups.

[0169] m and n are integers that satisfy 0≦m≦5, 0≦n≦3, and 0≦m+n≦5, but preferably integers that satisfy 1≦m≦3 and 0≦n≦2.

[0170] As the anionic moiety of the acid diffusion control agent represented by formula (S-1) or formula (S-2), examples of organic acid anions can be listed below, but are not limited to these. Furthermore, the following are all anionic moiety of organic acid anions having an iodine-substituted aromatic ring structure, but as anionic moiety of organic acid anions not having an iodine-substituted aromatic ring structure, a structure in which the iodine atom in the following formula is substituted by an atom or group other than the iodine atom, such as a hydrogen atom or other substituent, is preferred.

[0171] [Chemistry 26]

[0172] [Chemistry 27]

[0173] [Chemistry 28]

[0174] The onium cation portion of the acid diffusion control agent represented by formulas (S-1) and (S-2) is preferably the onium cation portion of structural unit B of the radiosensitive linear acid generating resin. Preferably, it is an onium cation containing an aromatic ring structure with fluorine atoms; more preferably, it is an onium cation represented by formula (Q-1); even more preferably, it is a strontium cation containing two or more aromatic ring structures with fluorine atoms; and most preferably, it is a strontium cation containing three aromatic ring structures with fluorine atoms.

[0175] The acid diffusion control agents represented by formulas (S-1) and (S-2) can also be synthesized by known methods, particularly salt exchange reactions. Known acid diffusion control agents can also be used as long as the effects of the present invention are not compromised.

[0176] These acid diffusion control agents can be used alone or in combination of two or more. The content of the acid diffusion control agent relative to the content of the radiosensitive linear acid generator (in the case of a radiosensitive linear acid generating resin, the total content of structural unit B in 100 parts by mass of the radiosensitive linear acid generating resin) is preferably 10% by mass or more, more preferably 25% by mass or more, and even more preferably 40% by mass or more. Furthermore, the stated proportion is preferably 500% by mass or less, more preferably 200% by mass or less, and even more preferably 100% by mass or less. This allows for excellent sensitivity or CDU performance when forming resist patterns.

[0177] Solvent The radiosensitive linear resin composition of this embodiment contains a solvent. The solvent is not particularly limited as long as it is capable of dissolving or dispersing at least one of the base resin (radiosensitive linear acid generating resin and resins), and any additives as needed.

[0178] Examples of solvents include: alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, and hydrocarbon solvents.

[0179] Examples of alcohol-based solvents include: Monool 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.

[0180] 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.

[0181] 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-acetone, acetophenone, etc.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] <Other arbitrary ingredients> The radiosensitive linear resin composition may contain any other components besides the aforementioned components. Examples of such other components include: crosslinking agents, accelerators, surfactants, compounds containing alicyclic skeletons, sensitizers, etc. These other components may also be used in combination, one or more at a time.

[0187] <Preparation Method of Radiation-Inducing Linear Resin Composition> The radiosensitive linear resin composition can be prepared, for example, by mixing a base resin (at least one of a radiosensitive linear acid generating resin and resins) and a solvent with any other desired components in a prescribed ratio. Preferably, the radiosensitive linear resin composition is filtered after mixing using, for example, a filter with a pore size of approximately 0.05 μm. 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.

[0188] <Pattern Formation Methods> The pattern forming method of this embodiment includes: Step (1) (hereinafter also referred to as "resist film formation step") involves directly or indirectly coating the radiosensitive linear resin composition onto a substrate to form a resist film. Step (2) of exposing the resist film (hereinafter also referred to as the "exposure step"); and The step (3) of developing the exposed resist film (hereinafter also referred to as the "development step").

[0189] According to the pattern forming method, high-quality resist patterns can be formed by using the radiosensitive linear resin composition with excellent sensitivity or CDU performance in the exposure step. The steps are described below.

[0190] [Resist Film Formation Steps] In this step (step (1)), a resist film is formed using the radiosensitive linear resin composition. Examples of substrates for forming the resist film include silicon wafers, silicon dioxide- or aluminum-coated wafers, and other previously known materials. Alternatively, organic or inorganic antireflective films disclosed in Japanese Patent Application Publication No. 6-12452 or Japanese Patent Application Publication No. 59-93448 may be formed on the substrate. Examples of coating methods include spin coating, cast coating, and roll coating. After coating, pre-baking (PB) may be performed 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.

[0191] In the case of immersion exposure, regardless of the presence or absence of water-repellent polymer additives such as high-fluorine-content resin 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 by 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.

[0192] [Exposure Steps] In this step (step (2)), a photomask (which may be impregnated by a liquid medium such as water) exposes the resist film formed in step (1), i.e., the resist film formation step, to radiation. 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, depending on the linewidth of the target pattern; or charged particle beams such as electron beams and alpha rays. 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.

[0193] When exposure is performed by immersion exposure, the immersion liquid used can be, for example, water or a fluorine-based inactive liquid. The immersion liquid is preferably a liquid that is transparent relative to the exposure wavelength and has a temperature coefficient of refractive index that is as small as possible to minimize the strain of the optical image projected onto the film. However, especially when the exposure light source is ArF excimer laser light (wavelength 193 nm), in addition to the above points, water is preferred in terms of ease of acquisition and ease of operation. 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 no effect on the optical coating on the lower surface of the lens. Distilled water is preferred as the water used.

[0194] Preferably, a post-exposure bake (PEB) is performed after the exposure, in which the acid generated by the radiosensitive 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.

[0195] [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.

[0196] As the developing solution used in the aforementioned development, in the case of alkaline development, examples include alkaline aqueous solutions prepared by dissolving at least one of the following alkaline compounds: sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, 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.

[0197] 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, ester solvents and ketone solvents are preferred. As an ester solvent, acetate solvents are preferred, more preferably n-butyl acetate or amyl acetate. As a ketone solvent, chain ketones are 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 developing solution besides organic solvents include, for example, water and silicone oil.

[0198] Examples of development methods include: immersing the substrate in a tank filled with developer for a certain time (immersion method); developing by using surface tension to accumulate developer on the substrate surface and allowing it to stand for a certain time (puddle method); spraying developer onto the substrate surface (spraying method); and continuously spraying developer onto a substrate rotating at a certain speed while scanning the developer nozzle at a certain speed (dynamic distribution method), etc. [Example]

[0199] The present invention will be specifically described below with reference to synthetic examples, embodiments, and comparative examples, but the present invention is not limited to the embodiments described below. Methods for measuring various physical properties are shown below.

[0200] [Mw and Mn] The Mw and Mn of the polymer were determined by gel permeation chromatography (GPC) using GPC columns manufactured by Tosoh Corporation (two "G2000HXL", one "G3000HXL", and one "G4000HXL") under the following conditions. Dissolution solvent: Tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.) Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Column temperature: 40℃ Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0201] [Synthesis Example] Synthesis of base resin (P-1) to base resin (P-18) The monomers were combined and copolymerized in tetrahydrofuran (THF) solvent, crystallized in methanol, and then repeatedly washed with hexane. After separation and drying, base resins (P-1) to (P-18) with the compositions shown below were obtained. The composition of the obtained base polymers was confirmed by 1H nuclear magnetic resonance (NMR), and Mw and dispersion (Mw / Mn) were confirmed by the GPC conditions described above. The types and amounts of each monomer are shown in Table 1. In the following structural formulas, Me is methyl, Et is ethyl, and iPr is isopropyl.

[0202] [Chemistry 29]

[0203] [Chemistry 30]

[0204] [Table 1] resin Structural Unit A Structural Unit B Structural Unit D Structural Unit E Other structural units Mw Mw / Mn type quantity type quantity type quantity type quantity type quantity Synthesis example 1 P-1 m-1 / m-2 20 / 20 m-3 10 M-1 20 m-6 30 - - 8500 1.7 Synthesis example 2 P-2 m-1 / m-2 20 / 20 m-3 10 M-2 20 m-6 30 - - 8700 1.7 Synthesis example 3 P-3 m-1 / m-2 20 / 20 m-3 10 M-3 20 m-6 30 - - 9200 1.8 Synthesis example 4 P-4 m-1 / m-2 20 / 20 m-4 10 M-4 20 m-6 30 - - 8600 1.7 Synthesis example 5 P-5 m-1 / m-2 20 / 20 m-3 10 M-5 20 m-6 30 - - 8300 1.7 Synthesis example 6 P-6 m-1 / m-2 20 / 20 m-3 10 M-6 20 m-6 30 - - 8600 1.6 Synthesis Example 7 P-7 m-1 / m-2 20 / 20 m-3 10 M-7 20 m-6 30 - - 8100 1.7 Synthesis example 8 P-8 m-1 / m-2 20 / 20 m-4 10 M-8 20 m-6 30 - - 8300 1.8 Synthesis example 9 P-9 m-1 / m-2 20 / 20 m-3 10 M-9 20 m-6 30 - - 8300 1.7 Synthesis example 10 P-10 m-1 / m-2 20 / 20 m-3 10 M-1 2 m-6 30 m-7 18 8400 1.7 Synthesis Example 11 P-11 m-1 / m-2 20 / 20 - - M-1 20 m-6 30 m-8 10 8900 1.7 Synthesis example 12 P-12 m-1 / m-2 20 / 20 - - M-2 20 m-6 30 m-9 10 9200 1.7 Synthesis example 13 P-13 m-1 / m-2 20 / 20 m-5 10 M-1 20 m-6 30 - - 8400 1.7 Synthesis example 14 P-14 m-1 / m-2 20 / 20 m-4 10 M-1 20 m-6 30 - - 8700 1.7 Synthesis Example 15 P-15 m-1 / m-2 20 / 20 m-3 10 - - m-6 30 m-7 20 8400 1.7 Synthesis example 16 P-16 m-1 / m-2 20 / 20 m-3 10 - - m-6 30 m-8 20 8300 1.7 Synthesis Example 17 P-17 m-1 60 - - M-3 15 - - m-7 25 7900 1.6 Synthesis Example 18 P-18 m-2 35 m-4 5 M-10 10 m-6 35 m-7 15 8000 1.8

[0205] The following shows the structures of radiosensitive linear acid generators PAG1 to PAG4 and PAGc1 used in the preparation of radiosensitive linear resin compositions.

[0206] [Chemistry 31]

[0207] [Example, Comparative Example] The components were dissolved in a solvent containing 100 ppm of FC-4430 manufactured by 3M as a surfactant, according to the composition shown in Table 2. The solution was then filtered using a 0.2 μm nylon filter to prepare the radiosensitive linear resin composition.

[0208] The components in Table 2 are as follows.

[0209] Organic solvent: propylene glycol monomethyl ether acetate (PGMEA) γ-Butyrolactone (GBL) Cyclohexanone (CHN) Propylene glycol monomethyl ether (PGME) diacetone alcohol (DAA) Ethyl lactate (EL)

[0210] Acid diffusion control agent (Q-1) ~ Acid diffusion control agent (Q-3) and acid diffusion control agent (Qc-1)

[0211] [Chemistry 32]

[0212] High-fluorine content resin F-1: Mw=9,000, Mw / Mn=1.9 [Chemistry 33]

[0213] [Evaluation of sensitivity based on EUV exposure] Using a spin coater (Tokyo Electron's "CLEAN TRACK ACT12"), an antireflective coating forming composition (Brewer Science's "ARC66") was applied to 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 10 nm. The various radiosensitive linear resin compositions shown in Table 1 were then applied to this lower antireflective film using the same spin coater, and the wafer was heated at 130°C for 60 seconds (PB). Afterward, the wafer was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 55 nm. This resist film was then exposed using an EUV scanner (ASML's "NXE3300" (numerical aperture NA 0.33, σ 0.9 / 0.6, quadrupole illumination, a mask with a 46 nm pitch hole pattern on the wafer, +20% bias)). PEB was applied to a hot plate at 120°C for 60 seconds, followed by development for 30 seconds using a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution to form a resist pattern with 23 nm apertures and 46 nm spacing. The exposure value used to form this resist pattern with 23 nm apertures and 46 nm spacing was set as the optimal exposure value (Eop), and the optimal exposure value was set as the sensitivity (mJ / cm²).

[0214] [CDU's Evaluation] The resist pattern with 23 nm apertures and 46 nm spacing was formed by irradiating the Eop obtained above with the same procedure as described above. The resist pattern was observed from the top of the pattern using a scanning electron microscope (Hitachi High-Technologies CG-5000). The aperture size was measured at 16 points within a 500 nm range and the average value was calculated. In addition, the average value was measured at a total of 500 points at random locations. The 3 sigma value was calculated based on the distribution of the measured values, and the calculated 3 sigma value was set as the evaluation value (nm) of CDU performance. Regarding CDU performance, the smaller the evaluation value, the smaller the aperture deviation over a long period, and the better. The results are shown in Table 2. Furthermore, the values ​​in parentheses in the sensitivity and CDU columns of Table 2 are the improvement rate (%) based on the evaluation results of Comparative Examples 3 to 4.

[0215] [Table 2] base resin (parts by weight) PAG (parts by weight) Acid diffusion control agent (parts by weight) solvent (parts by weight) additive (parts by weight) Sensitivity [mJ / cm 2] CDU [nm] Development defects Example 1 P-1 (100) - Qc-1 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.4 (-) A Example 2 P-2 (100) - Qc-1 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.4 (-) A Example 3 P-3 (100) - Qc-1 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.4 (-) A Example 4 P-4 (100) PAG3 (2.0) Qc-1 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.2 (8.5%) A Example 5 P-5 (100) - Qc-1 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.4 (-) A Example 6 P-6 (100) - Qc-1 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.4 (-) A Example 7 P-7 (100) - Qc-1 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.4 (-) A Example 8 P-8 (100) - Q-3 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.4 (-) A Example 9 P-9 (100) - Qc-1 (3.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.4 (-) A Example 10 P-10 (100) - Qc-1 (3.0) PGMEA / GBL (2,200 / 300) F-1 (3.0) 14 (12.5%) 2.4 (-) B Example 11 P-11 (100) PAG1 (10) Qc-1 (3.0) PGMEA / GBL (2,200 / 300) F-1 (3.0) 15 (6%) 2.2 (8.5%) A Example 12 P-11 (100) PAG3 (7.5) Qc-1 (3.0) PGMEA / GBL (2,200 / 300) F-1 (3.0) 14 (12.5%) 2.2 (8.5%) A Example 13 P-11 (100) PAG2 (4.0) Qc-1 (3.0) PGMEA / GBL (2,200 / 300) F-1 (3.0) 13 (19%) 2.2 (8.5%) A Example 14 P-12 (100) PAGc1 (7.5) Q-1 (5.0) PGMEA / PGME (2,000 / 500) F-1 (3.0) 15 (6%) 2.2 (8.5%) A Example 15 P-12 (100) PAGc1 (7.5) Q-2 (1.5) PGMEA / GBL (2,200 / 300) F-1 (3.0) 14 (12.5%) 2.2 (8.5%) A Example 16 P-13 (100) PAG4 (1.0) Q-3 (5.0) PGMEA / CHN / PGME (800 / 1, 500 / 200) F-1 (3.0) 14 (12.5%) 2.2 (8.5%) A Example 17 P-17 (100) PAG3 (8.5) Q-2 (5.5) PGMEA / PGME (2,200 / 300) F-1 (3.0) 14 (12.5%) 2.2 (8.5%) A Example 18 P-18 (100) PAG2 (4.5) Q-1 (10.0) PGMEA / DAA (2,000 / 500) F-1 (3.0) 13 (19%) 2.2 (8.5%) A Comparative Example 1 P-15 (100) - Q-1 (5.0) PGMEA / CHN (2,000 / 500) F-1 (3.0) 14 (12.5%) 2.2 (8.5%) C Comparative Example 2 P-16 (100) - Q-2 (2.0) PGMEA / CHN / PGME (400 / 2,000 / 100) F-1 (3.0) 14 (12.5%) 2.2 (8.5%) C Comparative Example 3 P-14 (100) PAGc1 (2.0) Qc-1 (1.5) PGMEA / PGME / EL (1,500 / 500 / 500) F-1 (3.0) 16 (-) 2.4 (-) A Comparative Example 4 P-11 (100) PAGc1 (10) Qc-1 (3.0) PGME / EL (500 / 2,000) F-1 (3.0) 16 (-) 2.4 (-) A

[0216] Regarding the evaluation results of the resist pattern formed by the EUV exposure, the sensitivity, CDU, and development residue of the radiosensitive linear resin composition of the embodiment were all good. [Industrial Applicability]

[0217] By using the described radiosensitive linear resin composition and resist patterning method, resist patterns with good sensitivity to exposure light, excellent CDU performance, and minimal development residue can be formed. Therefore, these are better suited for use in the fabrication processes of semiconductor devices that are expected to be further miniaturized in the future.

[0218] none

Claims

1. A radiosensitive linear resin composition, comprising: The resin comprises structural unit A having an acid-dissociable group and structural unit D having a phenolic hydroxyl group; And a solvent, wherein the structural unit D has a phenolic hydroxyl group and an alkyl group on the same aromatic ring, and in the aromatic ring of the structural unit D, an alkyl group is bonded to the carbon atom adjacent to the carbon atom to which the phenolic hydroxyl group is bonded; wherein the radiosensitive linear resin composition further satisfies at least one of the group consisting of the following conditions 1 and 2; Condition 1: the resin is a radiosensitive linear acid generating resin further comprising structural unit B, wherein structural unit B comprises an organic acid anion portion and an onium cation portion comprising an aromatic ring structure having a fluorine atom; Condition 2: further comprising an onium salt, wherein the onium salt comprises an organic acid anion portion and an onium cation comprising an aromatic ring structure having a fluorine atom, wherein the onium salt is not the radiosensitive linear acid generating resin, and the structural unit A is a structural unit represented by the following formula (1) or a structural unit represented by the following formula (4): In the formula (1), RT is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; RX is a monovalent hydrocarbon group having 1 to 20 carbon atoms; Cy represents an alicyclic structure with 3 to 20 ring members formed together with the carbon atoms it bonds to. In formula (4), Rc is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Lc is a single bond or a divalent linker; Rc1, Rc2, and Rc3 are each independently a monovalent hydrocarbon group with 1 to 20 carbon atoms; The structural unit D is the structural unit represented by the following formula (D); In formula (D), Rα is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; LCA is a single bond, -COO-*, or -O-; * is a bond on the aromatic ring side; R101 is a hydrogen atom; R102 is a straight-chain or branched alkyl group with 1 to 8 carbon atoms; nd3 is 0, md3 is 1, and m4 is 1 or 2; wherein, 2≦md3+m4≦2nd3+5 is satisfied. In formula (D), R102 is bonded to the carbon atom adjacent to the carbon atom bonded to the phenolic hydroxyl group, and R102 is an alkyl group; the structural unit B is a structural unit derived from the monomer represented by formula (2) or formula (3); in formulas (2) and (3), RA and RB are hydrogen atoms, fluorine atoms, methyl or trifluoromethyl; RY and RZ are independently hydrogen atoms, fluorine atoms or fluorinated hydrocarbon groups, at least one of which is a fluorine atom or a fluorinated hydrocarbon group; multiple RY and RZ may be the same or different; s is an integer from 1 to 20; R1 to R3 are independently monovalent hydrocarbon groups, at least one of which is an aromatic ring with a fluorine atom; R4 to R6 are independently monovalent hydrocarbon groups, at least one of which is an aromatic ring with a fluorine atom; Y1 is a single bond or -Y11-C(=O)-O-; Y11 is a divalent hydrocarbon group with 1 to 20 carbon atoms or a divalent hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Y2 is a single bond, methylene, ethyl, phenyl, fluorinated phenyl, -O-Y21-, -C(=O)-O-Y21- or -C(=O)-NH-Y21-;Y21 is an alkyldiyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, or an enylphenyl group, and may contain a carbonyl group, ester bond, ether bond, or hydroxyl group; the alkyldiyl group with 1 to 6 carbon atoms, the alkenyl group with 2 to 6 carbon atoms, and the enylphenyl group may also be substituted with a fluorine atom.

2. The radiosensitive linear resin composition as claimed in claim 1, wherein the onium cation comprising an aromatic ring structure having a fluorine atom is represented by the following formula (Q-1); in formula (Q-1), Ra1 and Ra2 each independently represent alkyl, cycloalkyl, alkoxy, cycloalkyloxy, alkoxycarbonyl, alkylsulfonyl, cycloalkylsulfonyl, hydroxyl, halogen atom, or halogenated hydrocarbon group; n1 represents an integer from 0 to 5, and when n1 is 2 or more, multiple Ra1s may be the same or different; n2 represents an integer from 0 to 5, and when n2 is 2 or more, multiple Ra2s may be the same or different; n3 represents an integer from 1 to 5, and when n3 is 2 or more, multiple Ra3s may be the same or different; Ra3 represents a fluorine atom, or a group formed by substituting an alkyl, cycloalkyl, alkoxy, cycloalkyloxy, alkoxycarbonyl, or alkylsulfonyl group with a fluorine atom; when n1 is 2 or more, multiple Ra1s may be linked together to form a ring; When n2 is 2 or more, multiple Ra2 can be connected to form a loop; when n1 is 1 or more and n2 is 1 or more, Ra1 and Ra2 can be connected to form a loop.

3. The radiosensitive linear resin composition as claimed in claim 1, wherein the resin comprises an iodine-substituted aromatic ring structure.

4. The radiosensitive linear resin composition as claimed in claim 1, satisfying condition 1, wherein the radiosensitive linear resin composition, in condition 1, further comprises at least one selected from the group consisting of: a radiosensitive linear acid generator comprising an organic acid anion moiety and an onium cation moiety, wherein, The radiosensitive linear acid generator is not the radiosensitive linear acid generating resin; and the acid diffusion control agent comprises an organic acid anion portion and an onium cation portion, and generates an acid with a higher pKa than the acid generated by the radiosensitive linear acid generator by irradiation with radiation, wherein the acid diffusion control agent is not the radiosensitive linear acid generating resin.

5. The radiosensitive linear resin composition of claim 1, satisfying condition 2, wherein the onium salt in condition 2 comprises at least one selected from the group consisting of: a radiosensitive linear acid generator comprising an organic acid anion portion and an onium cation portion; and an acid diffusion control agent comprising an organic acid anion portion and an onium cation portion, and which, upon irradiation by radiation, produces an acid having a higher pKa than an acid produced by the radiosensitive linear acid generator; at least one of the onium cation portion constituting the radiosensitive linear acid generator and the onium cation portion constituting the acid diffusion control agent is an onium cation comprising an aromatic ring structure having a fluorine atom.

6. The radiosensitive linear resin composition as claimed in claim 4, wherein the organic acid anionic portion selected from the group consisting of the radiosensitive linear acid generator and the acid diffusion control agent comprises an iodine-substituted aromatic ring structure.

7. The radiosensitive linear resin composition as claimed in claim 5, wherein the organic acid anionic portion selected from the group consisting of the radiosensitive linear acid generator and the acid diffusion control agent comprises an iodine-substituted aromatic ring structure.

8. 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 7 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.

9. The pattern forming method as claimed in claim 8, wherein the exposure is performed using extreme ultraviolet light or an electron beam.