Radiation-sensitive resin composition, method for forming a resist pattern, and polymer

Abstract

To provide a radiation-sensitive resin composition excellent in sensitivity, CDU performance and development defect suppression, a resist pattern forming method, and a polymer.SOLUTION: The radiation-sensitive resin composition contains a polymer having a first structural unit represented by formula (1) and a compound represented by formula (2).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a radiation-sensitive resin composition, a method for forming a resist pattern, and a polymer. [Background technology]

[0002] Radiation-sensitive resin compositions used in microfabrication by lithography generate acid in the exposed areas when irradiated with radiation such as far-ultraviolet light (ArF excimer laser light, wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm), electromagnetic waves such as extreme ultraviolet light (EUV) (wavelength 13.5 nm), and charged particle beams such as electron beams. A chemical reaction catalyzed by this acid causes a difference in the dissolution rate in the developer between the exposed and unexposed areas, thereby forming a resist pattern on the substrate.

[0003] Radiation-sensitive resin compositions are required to have good sensitivity to exposure light such as extreme ultraviolet light and electron beams, as well as excellent CDU (Critical Dimension Uniformity) performance and development defect suppression.

[0004] In response to these requirements, the types and molecular structures of polymers, acid generators, and other components used in radiation-sensitive resin compositions have been investigated, and their combinations have also been studied in detail (see Japanese Patent Publication Nos. 2010-134279, 2014-224984, and 2016-047815). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-134279 [Patent Document 2] Japanese Patent Publication No. 2014-224984 [Patent Document 3] Japanese Patent Publication No. 2016-047815 [Overview of the project] [Problems that the invention aims to solve]

[0006] As resist patterns become even finer, the required performance levels are increasing, and there is a need for radiation-sensitive resin compositions that can meet these requirements.

[0007] The present invention has been made based on the circumstances described above, and its objective is to provide a radiation-sensitive resin composition, a resist pattern formation method, and a polymer that are excellent in sensitivity, CDU performance, and suppression of development defects. [Means for solving the problem]

[0008] The invention made to solve the above problems is a radiation-sensitive resin composition (hereinafter also referred to as "composition (I)") containing a polymer having a first structural unit represented by the following formula (1) and whose solubility in a developer changes upon the action of an acid (hereinafter also referred to as "[A1] polymer") and a compound represented by the following formula (2) (hereinafter also referred to as "[Z] compound"). [ka] (In formula (1), R 1 R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 2 Ar is a group obtained by removing two hydrogen atoms bonded to one carbon atom from a substituted or unsubstituted aliphatic hydrocarbon ring structure with 3 to 30 members. 1 (This refers to a group obtained by removing one hydrogen atom from a substituted or unsubstituted aromatic hydrocarbon ring structure with 6 to 30 members.) [ka] (In formula (2), Z is an acid-dissociable group. L 1 This is *-O-CO- or -O-CO-O-. * indicates the bonding site with Z. Y is an (n+1) valence organic group with 1 to 30 carbon atoms that does not contain a cyclic acetal structure. A -represents a monovalent anionic group. n is an integer from 1 to 5. When n is 2 or more, 2 or more Z are the same or different from each other, and 2 or more L 1 are the same or different from each other. X + is a monovalent radiation-sensitive onium cation.)

[0009] Another invention made to solve the above problem is a polymer having a first structural unit represented by the following formula (1) and a third structural unit represented by the following formula (3-2), whose solubility in a developer changes by the action of an acid (hereinafter, also referred to as "[A2] polymer"), and a radiation-sensitive acid generator (hereinafter, also referred to as "[B] acid generator") A radiation-sensitive resin composition (hereinafter, also referred to as "composition (II)").

Chemical Formula

Chemical Formula

[0010] Another invention made to solve the above problems is a resist pattern forming method comprising the steps of directly or indirectly coating a substrate with the above-mentioned radiation-sensitive resin composition (composition (I) or composition (II)), exposing the resist film formed by the above coating, and developing the exposed resist film.

[0011] Another invention made to solve the above problems is the [A2] polymer described above. [Effects of the Invention]

[0012] The radiation-sensitive resin composition of the present invention exhibits excellent sensitivity, CDU performance, and development defect suppression. The resist pattern formation method of the present invention allows for the formation of resist patterns with good sensitivity, excellent CDU performance, and suppressed development defects. The polymer of the present invention can be suitably used as a component of the radiation-sensitive resin composition. Therefore, these can be suitably used in semiconductor device processing processes and the like, where further miniaturization is expected in the future. [Modes for carrying out the invention]

[0013] The radiation-sensitive resin composition, resist pattern formation method, and polymer of the present invention will be described in detail below.

[0014] <Radiation sensitive resin composition> Examples of the radiation-sensitive resin composition include the following compositions (I) and (II). Composition (I): Contains [A1] polymer and [Z] compound. Composition (II): Contains [A2] polymer and [B] acid generator. In this specification, polymers [A1] and [A2] may be collectively referred to as "[A] polymer".

[0015] As will be explained in more detail later, the [A2] polymer is included in the [A1] polymer, and the [B] acid generator is a radiation-sensitive acid generator other than the [Z] compound. Therefore, a radiation-sensitive resin composition containing the [A2] polymer and the [Z] compound is one embodiment of composition (I).

[0016] The radiation-sensitive resin compositions will be described below in the order of composition (I) and composition (II).

[0017] <Composition (I)> Composition (I) contains a [A1] polymer and a [Z] compound. Composition (I) usually contains an organic solvent (hereinafter also referred to as "[D] organic solvent"). Composition (I) may also contain, as preferred components, a radiation-sensitive acid generator other than the [Z] compound (hereinafter also referred to as "[B] acid generator") and / or an acid diffusion control agent other than the [Z] compound (hereinafter also referred to as "[C] acid diffusion control agent"). Composition (I) may also contain, as preferred components, a polymer with a higher fluorine atom content than the [A] polymer (hereinafter also referred to as "[F] polymer"). Composition (I) may contain other optional components as long as they do not impair the effects of the present invention.

[0018] Composition (I) contains the [A1] polymer and the [Z] compound, resulting in excellent sensitivity, CDU performance, and development defect suppression. The reason why composition (I) achieves the above effects through the above configuration is not entirely clear, but it can be inferred, for example, as follows: The [A1] polymer and the [Z] compound each have specific structures described later, which improves their solubility or insolubility in the developer in the exposed area. As a result, composition (I) is thought to have excellent sensitivity, CDU performance, and development defect suppression.

[0019] Composition (I) can be prepared by mixing, for example, a polymer and a compound, and optionally a [B] acid generator, a [C] acid diffusion control agent, a [D] organic solvent, and other optional components in predetermined proportions, and preferably by filtering the resulting mixture through a membrane filter with a pore size of 0.2 μm or less.

[0020] The following describes each component contained in composition (I).

[0021] <[A1] Polymer> [A1] polymers have a first structural unit represented by formula (1) described later (hereinafter also referred to as "structural unit (I)"), and are polymers whose solubility in a developer changes upon the action of an acid. [A1] polymers exhibit the property of changing their solubility in a developer upon the action of an acid due to the presence of structural unit (I). Composition (I) may contain one or more [A] polymers.

[0022] [A1] The polymer preferably further has structural units containing phenolic hydroxyl groups (hereinafter also referred to as "structural unit (II)"). [A1] The polymer may further have other structural units other than structural unit (I) and structural unit (II) (hereinafter also simply referred to as "other structural units"). [A1] The polymer may have one or more of each structural unit.

[0023] [A1] A polymer may have structural units that fall under two or more classifications (for example, a structural unit classified as structural unit (II) may also fall under structural units other than structural unit (II)). In this specification, such structural units will be treated as falling under the lower of the numbers indicated in parentheses in the structural unit classification.

[0024] The lower limit of the content of the [A1] polymer in composition (I) is preferably 50% by mass, more preferably 70% by mass, and even more preferably 80% by mass, relative to all components other than the [D] organic solvent contained in composition (I). The upper limit of the above content is preferably 99% by mass, and more preferably 95% by mass.

[0025] [A1] The lower limit of the polystyrene-equivalent weight-average molecular weight (Mw) of the polymer determined by gel permeation chromatography (GPC) is preferably 1,000, more preferably 3,000, even more preferably 4,000, even more preferably 5,000, and particularly preferably 6,000. The upper limit of the above Mw is preferably 50,000, more preferably 30,000, even more preferably 20,000, even more preferably 15,000, and particularly preferably 10,000. [A1] By setting the Mw of the polymer within the above range, the coating properties of composition (I) can be improved. [A1] The Mw of the polymer can be adjusted, for example, by adjusting the type and amount of polymerization initiator used in synthesis.

[0026] [A1] The upper limit of the ratio of Mw to the polystyrene-equivalent number-average molecular weight (Mn) of the polymer by GPC (hereinafter also referred to as "Mw / Mn" or "polydispersity") is preferably 2.5, more preferably 2.0, and still more preferably 1.8. The lower limit of the above ratio is usually 1.0, preferably 1.1, more preferably 1.2, and still more preferably 1.3.

[0027] [Methods for measuring Mw and Mn] The Mw and Mn values ​​of polymers in this specification are measured using gel permeation chromatography (GPC) under the following conditions. GPC columns: Two "G2000HXL" columns, one "G3000HXL" column, and one "G4000HXL" column from Tosoh Corporation. Column temperature: 40℃ Elution solvent: tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0028] [A1] Polymers can be synthesized, for example, by polymerizing monomers that give each structural unit using known methods.

[0029] The following describes each structural unit contained in polymer [A1].

[0030] [Structural Unit (I)] A structural unit (I) is a structural unit represented by the following formula (1).

[0031] [ka]

[0032] In the above equation (1), R 1 R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 2 Ar is a group obtained by removing two hydrogen atoms bonded to one carbon atom from a substituted or unsubstituted aliphatic hydrocarbon ring structure with 3 to 30 members. 1 This group is obtained by removing one hydrogen atom from a substituted or unsubstituted aromatic hydrocarbon ring structure with 6 to 30 ring members.

[0033] [A1] A polymer may have one or more structural units (I).

[0034] Structural unit (I) is a structural unit containing an acid-dissociable group. An "acid-dissociable group" is a group that substitutes for a hydrogen atom in a carboxyl group, hydroxyl group, etc., and dissociates upon the action of an acid to give a carboxyl group, hydroxyl group, etc. In formula (1) above, the group bonded to the etheric oxygen atom of the carbonyloxy group (the group represented by formula (a) below) is the acid-dissociable group (hereinafter also referred to as "acid-dissociable group (a)").

[0035] [ka]

[0036] In the above formula (a), R 2 and Ar 1 This is equivalent to formula (1) above. * indicates the bonding site between the carbonyloxy group and the etheric oxygen atom in formula (1) above.

[0037] By using composition (I), the acid-dissociable group (a) dissociates from structural unit (I) due to the action of acid generated from the [Z] compound, etc., upon exposure, and a difference in the solubility of the [A1] polymer in the developer solution occurs between the exposed and unexposed areas, thereby forming a resist pattern. The fact that the [A1] polymer contains the acid-dissociable group (a) in structural unit (I) is considered to be one of the factors that contribute to the excellent sensitivity of composition (I).

[0038] "Ring member number" refers to the number of atoms that make up the ring structure, and in the case of polycyclic structures, it refers to the number of atoms that make up this polycyclic structure. "Polycyclic structures" include not only spiro-type polycyclic structures where two rings share one common atom, and fused polycyclic structures where two rings share two common atoms, but also ring-assembly type polycyclic structures where two rings do not share an atom and are linked by a single bond. "Ring structure" includes "alicyclic structure" and "aromatic ring structure". "Alicyclic structure" includes "aliphatic hydrocarbon ring structure" and "aliphatic heterocyclic structure". "Aromatic ring structure" includes "aromatic hydrocarbon ring structure" and "aromatic heterocyclic structure". "A group obtained by removing X hydrogen atoms from a ring structure" means a group obtained by removing X hydrogen atoms that are bonded to the atoms that make up the ring structure.

[0039] R 1 From the viewpoint of copolymerization of the monomer that gives structural unit (I), a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0040] R 2Examples of aliphatic hydrocarbon ring structures with 3 to 30 ring members that give the properties include monocyclic saturated alicyclic structures such as cyclopropane, cyclobutane, cyclopentane, and cyclohexane; polycyclic saturated alicyclic structures such as norbornane and adamantane; monocyclic unsaturated alicyclic structures such as cyclobutene, cyclopentene, and cyclohexene; and polycyclic unsaturated alicyclic structures such as norbornene. Among these, monocyclic saturated alicyclic structures are preferred, and cyclohexane structures are more preferred.

[0041] Some or all of the hydrogen atoms bonded to the carbon atoms constituting the above aliphatic hydrocarbon ring structure may be substituted with substituents. Examples of substituents include halogen atoms such as fluorine atoms, hydroxyl groups, carboxyl groups, cyano groups, nitro groups, alkyl groups, alkoxy groups, alkoxycarbonyl groups, alkoxycarbonyloxy groups, acyl groups, acyloxy groups, oxo groups (=O), and the like.

[0042] As the above aliphatic hydrocarbon ring structure, an unsubstituted aliphatic hydrocarbon ring structure is preferred.

[0043] R 2 R is a group obtained by removing two hydrogen atoms bonded to one carbon atom from the above aliphatic hydrocarbon ring structure. In other words, R 2 This is a divalent group in which two bonds exist on one carbon atom that constitutes an aliphatic hydrocarbon ring structure. In formula (1) above, the etheric oxygen atom of the carbonyloxy group and Ar 1 R 2 It is bonded to the same carbon atom in the structure. Due to this structure, the acid-dissociable group (a) dissociates from structural unit (I) upon exposure to acid, and a carboxyl group is formed.

[0044] Ar 1Examples of aromatic hydrocarbon ring structures with 6 to 30 members that yield the desired result include benzene structures; condensed polycyclic aromatic hydrocarbon ring structures such as naphthalene, anthracene, fluorene, biphenylene, phenanthrene, and pyrene structures; and ring-assembled aromatic hydrocarbon ring structures such as biphenyl, terphenyl, binaphthalene, and phenylnaphthalene structures. Among these, the benzene structure is preferred.

[0045] Some or all of the hydrogen atoms bonded to the carbon atoms constituting the above aromatic hydrocarbon ring structure may be substituted with substituents. Examples of substituents include those similar to those exemplified as substituents that may be present in the above aliphatic hydrocarbon ring structure.

[0046] The acid-dissociable group (a) is preferably a 1-phenylcyclohexane-1-yl group.

[0047] [A1] The lower limit of the content of structural unit (I) in the polymer is preferably 1 mol%, more preferably 5 mol%, and still more preferably 10 mol%, relative to the total structural units constituting the polymer. The upper limit of the above content is preferably 60 mol%, more preferably 50 mol%, and still more preferably 40 mol%. By setting the content of structural unit (I) within the above range, the sensitivity, CDU performance, and development defect suppression of composition (I) can be further improved. Unless otherwise specified, the upper limit of numerical ranges described herein may be "less than or equal to" or "less than," and the lower limit may be "greater than or equal to" or "greater than." Furthermore, the upper and lower limits can be combined in any way.

[0048] [Structural Units (II)] Structural unit (II) is a structural unit containing a phenolic hydroxyl group. "Phenolenic hydroxyl group" refers to all hydroxyl groups directly attached to aromatic rings, not just hydroxyl groups directly attached to benzene rings. [A1] A polymer may contain one or more structural units (II).

[0049] In the case of KrF exposure, EUV exposure, or electron beam exposure, the presence of structural unit (II) in the [A1] polymer can further enhance the sensitivity of composition (I). Therefore, when the [A1] polymer has structural unit (II), composition (I) can be suitably used as a radiation-sensitive resin composition for KrF exposure, EUV exposure, or electron beam exposure.

[0050] Examples of structural units (II) include the structural unit represented by the following formula (3-1) (hereinafter referred to as structural unit (II-1)).

[0051] [ka]

[0052] In the above equation (3-1), R 3 L is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 2 The bond is a single bond, -COO-, -O-, or -CONH-. 2 R is a group obtained by removing (s+t+1) hydrogen atoms from an aromatic hydrocarbon ring structure with 6 to 30 ring members. s is an integer from 1 to 3. t is an integer from 0 to 8. When t is 1, R 4 is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. If t is 2 or more, multiple R 4 These are either identical or different from each other, and are halogen atoms or monovalent organic groups having 1 to 20 carbon atoms, or multiple R 4 Two or more of these can be combined with each other to form an alicyclic structure with 4 to 20 members, along with the carbon chain to which they are bonded.

[0053] "Number of carbon atoms" refers to the number of carbon atoms that make up a group. "Organic group" refers to a group that contains at least one carbon atom. The "valence" of a group refers to the number of atoms to which that group is bonded.

[0054] R 3 From the viewpoint of copolymerization of the monomer that gives structural unit (II-1), a hydrogen atom or a methyl group is preferred.

[0055] L 2 A single bond or a -COO- is preferred.

[0056] Ar 2 Examples of aromatic hydrocarbon ring structures with 6 to 30 ring members that give the above formula (1) include Ar 1 Examples of aromatic hydrocarbon ring structures with 6 to 30 member numbers that give the desired effect include those similar to those exemplified. Among these, the benzene structure is preferred.

[0057] s is preferably 1 or 2, with 1 being more preferred.

[0058] R 4 In this context, the halogen atom is either a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0059] R 4 Examples of monovalent organic groups having 1 to 20 carbon atoms include monovalent hydrocarbon groups having 1 to 20 carbon atoms, groups (α) containing a divalent heteroatom-containing group between the carbon-carbon bonds of the hydrocarbon group, groups (β) in which some or all of the hydrogen atoms of the hydrocarbon group or group (α) are replaced with a monovalent heteroatom-containing group, and groups (γ) which are combinations of the hydrocarbon group, group (α), or group (β) with a divalent heteroatom-containing group.

[0060] "Hydrogen groups" include "aliphatic hydrocarbon groups" and "aromatic hydrocarbon groups." "Aliphatic hydrocarbon groups" include "saturated hydrocarbon groups" and "unsaturated hydrocarbon groups." From another perspective, "aliphatic hydrocarbon groups" include "chain hydrocarbon groups" and "alicyclic hydrocarbon groups." A "chain hydrocarbon group" is a hydrocarbon group that does not contain a cyclic structure and is composed only of a chain structure, and includes both linear hydrocarbon groups and branched hydrocarbon groups. An "alicyclic hydrocarbon group" is a hydrocarbon group that contains only an alicyclic structure as its ring structure and does not contain an aromatic ring structure, and includes both monocyclic and polycyclic alicyclic hydrocarbon groups. However, it is not necessary to be composed only of an alicyclic structure, and it may contain a chain structure as part of it. An "aromatic hydrocarbon group" is a hydrocarbon group that contains an aromatic ring structure as its ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and it may contain a chain structure or an alicyclic structure as part of it.

[0061] Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include monovalent linear hydrocarbon groups having 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms.

[0062] Examples of monovalent chain hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, isobutyl, and tert-butyl; alkenyl groups such as ethenyl, propenyl, butenyl, and 2-methylpropane-1-en-1-yl; and alkynyl groups such as ethynyl, propynyl, and butynyl.

[0063] Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms include monocyclic alicyclic saturated hydrocarbon groups such as cyclopentyl and cyclohexyl groups; polycyclic alicyclic saturated hydrocarbon groups such as norbornyl, adamantyl, tricyclodecyl, and tetracyclododecyl groups; monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopentenyl and cyclohexenyl groups; and polycyclic alicyclic unsaturated hydrocarbon groups such as norborneyl, tricyclodecenyl, and tetracyclododecenyl groups.

[0064] Examples of monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms include aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthryl groups; and aralkyl groups such as benzyl, phenethyl, naphthylmethyl, and anthrylmethyl groups.

[0065] Examples of heteroatoms that constitute a monovalent or divalent heteroatom-containing group include oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, silicon atoms, halogen atoms, and the like.

[0066] Examples of monovalent heteroatom-containing groups include halogen atoms, hydroxyl groups, carboxyl groups, cyano groups, amino groups, sulfanyl groups (-SH), and oxo groups (=O).

[0067] Examples of divalent heteroatom-containing groups include -O-, -CO-, -S-, -CS-, -NR'-, and groups formed by combining two or more of these (e.g., -COO-, -CONR'-, etc.). R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of monovalent hydrocarbon groups having 1 to 10 carbon atoms represented by R' include those with 1 to 10 carbon atoms among the groups exemplified above as "monovalent hydrocarbon groups having 1 to 20 carbon atoms".

[0068] Multiple R 4 Examples of alicyclic structures with 4 to 20 members, formed by two or more of these elements being combined with the carbon chains to which they are bonded, include monocyclic saturated alicyclic structures such as cyclobutane, cyclopentane, and cyclohexane; polycyclic saturated alicyclic structures such as norbornane, adamantane, tricyclodecane, and tetracyclododecane; monocyclic unsaturated alicyclic structures such as cyclopropene, cyclobutene, cyclopentene, and cyclohexene; and polycyclic unsaturated alicyclic structures such as norbornene, tricyclodecene, and tetracyclododecene.

[0069] For t, 0 or 1 is preferred, and 0 is more preferred.

[0070] Examples of structural units (II-1) include structural units represented by the following formulas (3-1-1) to (3-1-18) (hereinafter also referred to as "structural units (II-1-1) to (II-1-18)"). Among these, structural units (3-1-1), structural units (3-1-3), structural units (3-1-8), structural units (3-1-9), structural units (3-1-12), or combinations thereof are preferred.

[0071] [ka]

[0072] In the above equations (3-1-1) to (3-1-18), R 3 This is equivalent to equation (3-1) above.

[0073] [A1]When the polymer has structural unit (II-1), the lower limit of the content of structural unit (II-1) in the [A1] polymer is preferably 20 mol%, more preferably 30 mol%, and even more preferably 40 mol%, relative to the total structural units constituting the [A1] polymer. The upper limit of the above content is preferably 70 mol%, more preferably 60 mol%, and even more preferably 50 mol%.

[0074] As monomers that provide structural unit (II), for example, monomers in which the hydrogen atoms of the phenolic hydroxyl group (-OH) are replaced with acetyl groups, such as 4-acetoxystyrene and 3,5-diacetoxystyrene, can also be used. In this case, for example, after polymerizing the above monomer, the resulting polymerization product can be hydrolyzed in the presence of a base such as an amine to synthesize a [A1] polymer having structural unit (II).

[0075] From another perspective, among the structural units (II-1), the structural unit represented by formula (3-2), described later (hereinafter also referred to as "structural unit (IIa)") is preferred. In this case, the ability to suppress development defects can be further improved.

[0076] (Structural Unit (IIa)) Structural unit (IIa) is a type of structural unit (structural unit (II)) containing a phenolic hydroxyl group, and is represented by the following formula (3-2). Formula (3-2) is a type of formula (3-1) above, with the bond position of the hydroxyl group specified. Among the [A1] polymers, polymers that further contain structural unit (IIa) are called [A2] polymers.

[0077] [ka]

[0078] In the above equation (3-2), R 3 , L 2 , R 4 Ar 2 , s and t are equivalent to those in formula (3-1) above. However, when s is 1, the hydroxyl group is Ar 2 Among the carbon atoms that make up the L 2 It bonds to a carbon atom adjacent to the carbon atom it bonds to. If s is 2 or more, at least one hydroxyl group is Ar 2 Among the carbon atoms that make up the L 2 It bonds to a carbon atom adjacent to the carbon atom it is bonded to.

[0079] Structural unit (IIa) is a structural unit represented by formula (3-1) above, in which at least one hydroxyl group is Ar 2 Among the carbon atoms that make up the L 2 It is bonded to a carbon atom adjacent to the carbon atom to which it is bonded. In other words, at least one hydroxyl group and L 2 Ar 2 They are coupled to each other at the ortho position.

[0080] The polymer [A1] can further improve its ability to suppress development defects by possessing structural unit (IIa). The reason for this effect is not entirely clear, but it can be inferred, for example, as follows: As mentioned above, the specific structures of the polymer [A] and compound [Z] improve their solubility or insolubility in the developer in the exposed area. Furthermore, the presence of structural unit (IIa) in the polymer [A] allows for appropriate adjustment of the interaction between the polymer [A] and compound [Z], etc., further improving its solubility or insolubility in the developer in the exposed area. As a result, composition (I) is thought to exhibit superior ability to suppress development defects.

[0081] The structural unit (IIa) is preferably the structural unit represented by formula (3-1-3) (structural unit (II-1-3)), the structural unit represented by formula (3-1-8) (structural unit (II-1-8)), the structural unit represented by formula (3-1-12) (structural unit (II-1-12)), or a combination thereof, with structural unit (II-1-3), structural unit (II-1-12), or a combination thereof being more preferable. In this case, the ability to suppress development defects can be further improved.

[0082] [A1]When the polymer has structural unit (IIa), the lower limit of the content of structural unit (IIa) in the [A1] polymer is preferably 10 mol%, more preferably 20 mol%, and even more preferably 30 mol%, relative to the total structural units constituting the [A1] polymer. The upper limit of the above content is preferably 70 mol%, more preferably 60 mol%, and even more preferably 50 mol%.

[0083] [A1] If the polymer has structural unit (IIa), the [A1] polymer may also contain structural units other than structural unit (IIa) among structural unit (II) (hereinafter also referred to as "structural unit (IIb)"). In this case, the content ratio of structural unit (IIb) in the [A1] polymer can be appropriately adjusted based on the content ratio of structural unit (IIa) described above, within the range of the content ratio of structural unit (II) described above.

[0084] [Other structural units] Other structural units include, for example, structural units containing acid-dissociable groups other than acid-dissociable group (a) (hereinafter also referred to as "structural unit (III)"), structural units containing lactone structures, cyclic carbonate structures, sultone structures, or combinations thereof (hereinafter also referred to as "structural unit (IV)"), and structural units containing alcoholic hydroxyl groups (hereinafter also referred to as "structural unit (V)").

[0085] (Structural Unit (III)) Structural unit (III) is a structural unit that contains an acid-dissociable group other than the acid-dissociable group (a) (hereinafter also referred to as "acid-dissociable group (b)"). Structural unit (III) is a different structural unit from structural unit (I).

[0086] Examples of structural units (III) include structural units represented by the following formulas (III-1) to (III-3) (hereinafter also referred to as "structural units (III-1) to (III-3)"). For example, in the following formula (III-1), -C(R X )(R Y )(R Z ) corresponds to the acid-dissociable group (b).

[0087] [ka]

[0088] In the above equations (III-1) to (III-3), R T Each of these is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0089] In the above equation (III-1), R X R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. Y and R Z Each of these groups is either a monovalent hydrocarbon group having 1 to 20 carbon atoms, or these groups are combined with each other to form a saturated alicyclic structure with 3 to 20 member atoms. However, RY and R Z constitute the above saturated alicyclic structure, R X is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms.

[0090] In the above formula (III-2), R A is a hydrogen atom. R B and R C are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R D is R A , R B and R C is a divalent hydrocarbon group having 1 to 20 carbon atoms that constitutes an unsaturated alicyclic structure having 4 to 20 ring members together with the carbon atoms to which each is bonded.

[0091] In the above formula (III-3), R U and R V are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, R W is a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R U and R V together constitute an alicyclic structure having 3 to 20 ring members together with the carbon atoms to which they are bonded, or R U and R W together constitute an aliphatic heterocyclic structure having 4 to 20 ring members together with the carbon atom to which R U is bonded and the oxygen atom to which R W is bonded.

[0092] R T is preferably a hydrogen atom or a methyl group from the viewpoint of copolymerizability of the monomer that provides the structural unit (III).

[0093] R X , R Y , R Z , R B , R C , R U , R V or R W as the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by, for example, in the above formula (3-1), R4 Among the monovalent organic groups having 1 to 20 carbon atoms represented by , examples include the same groups as those exemplified as the monovalent hydrocarbon groups having 1 to 20 carbon atoms.

[0094] The above R X Examples of the substituent that the hydrocarbon group represented by may have include those in R in the above formula (1) 2 Examples include the same substituents as those exemplified as the substituents that the aliphatic hydrocarbon ring structure providing may have.

[0095] R Y and R Z are combined with each other to form a saturated alicyclic structure having 3 to 20 ring members together with the carbon atoms to which they are bonded, and R U and R V Examples of the alicyclic structure having 3 to 20 ring members formed by being combined with each other together with the carbon atoms to which they are bonded include: monocyclic saturated alicyclic structures such as cyclopropane structure, cyclobutane structure, cyclopentane structure, and cyclohexane structure; polycyclic saturated alicyclic structures such as norbornane structure, adamantane structure, tricyclodecane structure, and tetracyclododecane structure; monocyclic unsaturated alicyclic structures such as cyclopropene structure, cyclobutene structure, cyclopentene structure, and cyclohexene structure; and polycyclic unsaturated alicyclic structures such as norbornene structure, tricyclodecene structure, and tetracyclododecene structure.

[0096] R D Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by include the above R X , R Y , R Z , R B , R C , R U , R V or R W Examples include groups obtained by removing one hydrogen atom from the groups exemplified as the monovalent hydrocarbon groups having 1 to 20 carbon atoms represented by .

[0097] R D is R A , R B and R CExamples of unsaturated alicyclic structures with 4 to 20 member numbers, formed by these structures together with the carbon atoms to which they are bonded, include monocyclic unsaturated alicyclic structures such as cyclobutene, cyclopentene, and cyclohexene structures, and polycyclic unsaturated alicyclic structures such as norbornene structures.

[0098] R U and R W They are combined with each other R U The carbon atoms and R that are bonded to it W Examples of aliphatic heterocyclic structures with 4 to 20 member numbers formed together with the bonded oxygen atom include saturated oxygen-containing heterocyclic structures such as oxacyclobutane, oxacyclopentane, and oxacyclohexane; and unsaturated oxygen-containing heterocyclic structures such as oxacyclobutene, oxacyclopentene, and oxacyclohexene.

[0099] R Y and R Z If R is a monovalent hydrocarbon group with 1 to 20 carbon atoms, Y and R Z A chain-like hydrocarbon group is preferred, an alkyl group is preferred, and a methyl group is more preferred. In this case, R X The preferred group is a substituted or unsubstituted aromatic hydrocarbon group, more preferably an unsubstituted aryl group, and even more preferably a phenyl group.

[0100] R Y and R Z When these are combined with each other to form a saturated alicyclic structure with 3 to 20 member atoms, the saturated alicyclic structure is preferably a monocyclic saturated alicyclic structure or a polycyclic saturated alicyclic structure, and more preferably a cyclopentane structure, an adamantane structure, or a tetracyclododecane structure. In this case, R X Preferably, the group is a substituted or unsubstituted linear hydrocarbon group, more preferably an unsubstituted alkyl group, and even more preferably a methyl group or an ethyl group.

[0101] Structural unit (III-1) is preferred as structural unit (III).

[0102] As the structural unit (III-1), the structural unit represented by the following formulas (III-1-1) to (III-1-4) is preferred.

[0103] [ka]

[0104] In the above equations (III-1-1) to (III-1-4), R T This is equivalent to equation (III-1) above.

[0105] [A1]When the polymer has structural unit (III), the lower limit of the content of structural unit (III) is preferably 10 mol%, and more preferably 20 mol%, relative to the total structural units constituting the polymer. The upper limit of the above content is preferably 50 mol%, and more preferably 40 mol%.

[0106] (Structural Unit (IV)) Structural unit (IV) is a structural unit that includes a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof.

[0107] Examples of structural units (IV) include structural units represented by the following formula.

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] In the above formula, R L1 These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0113] The structural unit (IV) is preferably a structural unit that includes a lactone structure, a sultone structure, or a combination thereof.

[0114] [A1]When the polymer has structural unit (IV), the lower limit of the content of structural unit (IV) is preferably 5 mol%, and more preferably 10 mol%, relative to the total structural units constituting the polymer. The upper limit of the above content is preferably 30 mol%, and more preferably 20 mol%.

[0115] (Structural unit (V)) Structural unit (V) is a structural unit containing an alcoholic hydroxyl group. By further including structural unit (V), the solubility in the developer can be adjusted to a more appropriate degree. [A1] The polymer may contain one or more structural units (V).

[0116] Examples of structural units (V) include structural units represented by the following formula.

[0117] [ka]

[0118] In the above formula, R L2 These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0119] [A1]When the polymer has structural units (V), the lower limit of the content of structural units (V) is preferably 5 mol%, and more preferably 15 mol%, relative to the total structural units in the polymer. The upper limit of the above content is preferably 30 mol%, and more preferably 20 mol%.

[0120] <[Z] compound> [Z] compound is a compound represented by the following formula (2). Composition (I) may contain one or more [Z] compounds.

[0121] [ka]

[0122] In the above formula (2), Z is an acid-dissociable group. 1 is *-O-CO- or -O-. * indicates the bonding site with Z. Y is an (n+1) valence organic group with 1 to 30 carbon atoms that does not contain a cyclic acetal structure. n is an integer from 1 to 5. If n is 2 or greater, then 2 or more Zs are either identical or different, and 2 or more Ls are identical or different. 1 They are either identical or different from each other. - X is a monovalent anionic group. + It is a monovalent radiation-sensitive onium cation.

[0123] Below, in equation (2) above, (ZL 1 ) n -YA - The structure represented by X is also called the "anion part". + The structure represented by is also called the "cationic part". Furthermore, Z in the above formula (2) is also called the "acid-dissociable group (z)", and Y is also called the "skeletal structure (Y)", A - This is also called an "anionic group".

[0124] Depending on the type of anionic group, the [Z] compound has the effect of generating acid in composition (I) upon irradiation with radiation, or controlling the diffusion phenomenon of acid generated by exposure from the [B] acid generator described later in the resist film, thereby suppressing undesirable chemical reactions in the unexposed areas (e.g., dissociation reactions of acid-dissociable groups). In other words, depending on the type of anionic group, the [Z] compound functions as a radiation-sensitive acid generator or an acid diffusion control agent (quencher) in composition (I).

[0125] When the [Z] compound functions as a radiation-sensitive acid generator, the radiation can be similar to, for example, the exposure light in the exposure step of the resist pattern formation method described later. The acid generated from the [Z] compound by irradiation with radiation causes the acid-dissociable groups (a) etc. contained in the structural unit (I) of the [A1] polymer to dissociate, generating carboxyl groups etc., and a difference in the solubility of the resist film in the developer between the exposed and unexposed areas occurs, thereby forming a resist pattern.

[0126] When the [Z] compound functions as an acid diffusion control agent, it generates acid in the exposed area, increasing the solubility or insolubility of the [A1] polymer in the developer. Meanwhile, in the unexposed area, the anion exhibits a high acid-catching function, acting as a quencher and capturing the acid diffusing from the exposed area. This improves the roughness at the interface between the exposed and unexposed areas, and also improves the contrast between the exposed and unexposed areas, thereby improving resolution.

[0127] Regardless of the function of the [Z] compound in composition (I) as described above, the inclusion of the [Z] compound in composition (I) is considered to be one of the factors contributing to composition (I)'s excellent suppression of development defects.

[0128] When the [Z] compound functions as a radiation-sensitive acid generator, the lower limit of the [Z] compound content in composition (I) is preferably 1 part by mass, more preferably 2 parts by mass, per 100 parts by mass of the [A1] polymer. The upper limit of the above content is preferably 10 parts by mass, more preferably 5 parts by mass.

[0129] When the [Z] compound functions as an acid diffusion control agent, the lower limit of the [Z] compound content in composition (I) is preferably 1 part by mass, more preferably 2 parts by mass, per 100 parts by mass of the [A1] polymer. The upper limit of the above content is preferably 10 parts by mass, more preferably 5 parts by mass.

[0130] The following describes the various structures of the [Z] compound.

[0131] [Anion Club] The anion part is (ZL in equation (2) above) 1 ) n -YA - The structure is represented by [formula]. n is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0132] (L 1 ) L 1 These are groups bonded to the acid-dissociable group (a) and the skeletal structure (Y), respectively, as described later. 1 If it is *-O-CO-, a carboxyl group is formed when the acid-dissociable group (z) dissociates. 1 If the group is -O-, a hydroxyl group is formed when the acid-dissociable group (z) dissociates.

[0133] (Acid dissociable group (z)) The acid-dissociating group (z) is L 1 This is a group bonded to the compound. The acid-dissociable group (z) is a group that substitutes a hydrogen atom in a carboxyl group or hydroxyl group, and dissociates upon the action of an acid to give a carboxyl group or hydroxyl group. The presence of the acid-dissociable group (z) in the [Z] compound is considered to be one of the factors that contribute to composition (I) exhibiting excellent suppression of development defects.

[0134] Examples of acid-dissociable groups (z) include the groups represented by the following formulas (z-1) to (z-3) (hereinafter also referred to as "acid-dissociable groups (z-1) to (z-3)").

[0135] [ka]

[0136] In the above equations (z-1) to (z-3), * represents L in equation (2) above. 1 This shows the binding site.

[0137] In the above equation (z-1), R Z1 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms.Z2 and R Z3 Each of these groups is either a monovalent hydrocarbon group having 1 to 20 carbon atoms, or these groups can be combined with each other to form a saturated alicyclic structure with 3 to 20 member atoms.

[0138] In the above equation (z-2), R Z4 R is a hydrogen atom. Z5 and R Z6 Each of these is independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. Z7 R Z4 , R Z5 and R Z6 These are divalent hydrocarbon groups with 1 to 20 carbon atoms that, together with the carbon atoms to which they are bonded, constitute an unsaturated alicyclic structure with 4 to 20 ring members.

[0139] In the above equation (z-3), R Z8 and R Z9 Each of these is independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R Z10 is a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R Z8 and R Z9 These are combined with each other to form an alicyclic structure with 3 to 20 member atoms, or R Z8 and R Z10 They are combined with each other R Z8 The carbon atoms and R that are bonded to it Z10 Together with the oxygen atoms to which it is bonded, it forms an aliphatic heterocyclic structure with 4 to 20 ring members.

[0140] R Z1 , R Z2 , R Z3 , R Z5 , R Z6 , R Z8 , R Z9 or R Z10 As a monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the above formula (3-1), for example, R 4 Among the monovalent organic groups having 1 to 20 carbon atoms represented by , examples include groups similar to those exemplified as monovalent hydrocarbon groups having 1 to 20 carbon atoms.

[0141] R Z2 and R Z3 These are combined with each other to form a saturated alicyclic structure with 3 to 20 member atoms, and R Z8 and R Z9 When these are combined with each other, the resulting alicyclic structure with 3 to 20 members, formed together with the carbon atoms to which they are bonded, is, for example, R in formula (3-1) above. Y and R Z These are combined with each other to form a saturated alicyclic structure with 3 to 20 ring members, and the R of formula (III-3) above U and R V Examples include structures similar to those exemplified, where these elements are combined with each other to form an alicyclic structure with 3 to 20 member atoms, along with the carbon atoms to which they bond.

[0142] R Z7 As a divalent hydrocarbon group having 1 to 20 carbon atoms represented by the above formula (3-1), for example, R 4 Examples include monovalent organic groups with 1 to 20 carbon atoms, as represented by [formula], and groups obtained by removing one hydrogen atom from the group exemplified as a monovalent hydrocarbon group with 1 to 20 carbon atoms.

[0143] R Z7 R Z4 , R Z5 and R Z6 As an unsaturated alicyclic structure with 4 to 20 ring members, formed together with the carbon atoms to which each is bonded, for example, R in formula (III-2) above D R A , R B and R C Examples include structures similar to those exemplified as unsaturated alicyclic structures with 4 to 20 member numbers, each formed by the carbon atoms to which it is bonded.

[0144] R Z8 and R Z10 They are combined with each other R Z8 The carbon atoms and R that are bonded to it Z10 As an aliphatic heterocyclic structure with 4 to 20 ring members formed together with the oxygen atom to which it is bonded, for example, the R in formula (III-3) above U and RW They are combined with each other R U The carbon atoms and R that are bonded to it W Examples include structures similar to those exemplified as aliphatic heterocyclic structures with 4 to 20 member numbers, formed together with the bonded oxygen atoms.

[0145] Some or all of the hydrogen atoms bonded to the atoms constituting the hydrocarbon group or ring structure may be substituted with substituents. Examples of substituents include monovalent heteroatom-containing groups and monovalent organic groups having 1 to 20 carbon atoms. Monovalent heteroatom-containing groups and monovalent organic groups having 1 to 20 carbon atoms are R in formula (3-1) above. 4 It is explained in [the relevant section].

[0146] Preferred substituents include halogen atoms, hydroxyl groups, monovalent hydrocarbon groups having 1 to 20 carbon atoms, groups (α) containing a divalent heteroatom-containing group between the carbon-carbon bonds of the hydrocarbon group, groups (β) in which some or all of the hydrogen atoms of the hydrocarbon group or group (α) are replaced with a monovalent heteroatom-containing group, and groups (γ) which are combinations of the hydrocarbon group, group (α), or group (β) with a divalent heteroatom-containing group.

[0147] Furthermore, a monovalent group containing an acid-dissociable group (z) is also preferred as a substituent. Examples of such substituents include *-L A1 -L 1 -Z represents the group (L A1 This is a divalent linking group, which will be described later. 1 And Z are equivalent to formula (2) above. * indicates the bonding site with the acid-dissociable group (z). ) are examples.

[0148] R Z1 The group is preferably a chain-like hydrocarbon group, more preferably an alkyl group, and even more preferably a methyl group, an ethyl group, an i-propyl group, or a tert-butyl group.

[0149] R Z2 and R Z3 If R is a monovalent hydrocarbon group with 1 to 20 carbon atoms, Y and R ZAs , a chain hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group is preferable; an alkyl group, a monocyclic saturated alicyclic hydrocarbon group, a polycyclic saturated alicyclic hydrocarbon group or an aryl group is more preferable; and a methyl group, an ethyl group, an i-propyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group or a phenyl group is further preferable.

[0150] R Z2 and R Z3 are combined with each other to form a saturated alicyclic structure having 3 to 20 ring members together with the carbon atoms to which they are bonded, the saturated alicyclic structure is preferably a monocyclic saturated alicyclic structure or a polycyclic saturated alicyclic structure, and more preferably a cyclopentane structure, a cyclohexane structure, a norbornane structure, an adamantane structure, a tricyclodecane structure or a tetracyclododecane structure.

[0151] R Z5 As , a hydrogen atom is preferable.

[0152] R Z6 As , a hydrogen atom or a chain hydrocarbon group is preferable, a hydrogen atom or an alkyl group is more preferable, and a hydrogen atom or a methyl group is further preferable.

[0153] R Z7 and R Z4 , R Z5 and R Z6 as the unsaturated alicyclic structure having 4 to 20 ring members formed together with the respective carbon atoms to which they are bonded, a monocyclic unsaturated alicyclic structure is preferable, and a cyclopentene structure or a cyclohexene structure is more preferable.

[0154] R Z8 and R Z9 are each a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and R Z10 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms (Pattern 1) will be described below. In this case, R Z8 and R Z9is preferably a hydrogen atom or a chain hydrocarbon group, more preferably a hydrogen atom or an alkyl group, and still more preferably a hydrogen atom, a methyl group, an ethyl group, or an i-propyl group. R in the above case Z10 is preferably a chain hydrocarbon group or an alicyclic hydrocarbon group, more preferably an alkyl group or a polycyclic alicyclic saturated hydrocarbon group, and still more preferably a methyl group, an ethyl group, an adamantyl group, or a tricyclododecyl group.

[0155] R Z8 and R Z10 are combined with each other, and R Z8 together with the carbon atom to which R is bonded and R Z10 together with the oxygen atom to which the group is bonded to form a substituted or unsubstituted aliphatic heterocyclic structure having 4 to 20 ring members (Pattern 3) will be described. In this case, the aliphatic heterocyclic structure is preferably a saturated oxygen-containing heterocyclic structure, more preferably an oxacyclohexane structure.

[0156] As the acid-dissociable group (z), an acid-dissociable group (z-1) or (z-3) is preferred.

[0157] Examples of the acid-dissociable group (z-1) include groups represented by the following formulas (z-1-1) to (z-1-26) (hereinafter also referred to as "acid-dissociable groups (z-1-1) to (z-1-26)").

[0158] [[Chemical structure]]

[0159] In the above formulas (z-1-1) to (z-1-26), * has the same definition as in the above formula (z-1).

[0160] Examples of the acid-dissociable group (z-3) include groups represented by the following formulas (z-3-1) to (z-3-11) (hereinafter also referred to as "acid-dissociable groups (z-3-1) to (z-3-11)").

[0161] [[Chemical structure]]

[0162] In the above equations (z-3-1) to (z-3-11), * is equivalent to the above equation (z-3).

[0163] (Skeletal structure (Y)) The skeletal structure (Y) is an (n+1) valence organic group having 1 to 30 carbon atoms and not containing a cyclic acetal structure. The term "cyclic acetal structure" includes not only monocyclic acetal structures but also polycyclic acetal structures. Polycyclic acetal structures include, for example, spiro-type polycyclic structures in which a monocyclic acetal structure such as dioxolane and an aliphatic hydrocarbon ring structure such as cyclohexane share one covalent atom, as well as condensed polycyclic structures in which the two rings share two covalent atoms.

[0164] Examples of (n+1) valent organic groups having 1 to 30 carbon atoms that do not contain the above-mentioned cyclic acetal structure include, for example, monovalent hydrocarbon groups having 1 to 30 carbon atoms, groups (α) containing a divalent heteroatom-containing group between the carbon-carbon bonds of the hydrocarbon group, groups (β) in which some or all of the hydrogen atoms of the hydrocarbon group or group (α) are replaced with a monovalent heteroatom-containing group, and groups (γ) which are combinations of the hydrocarbon group, group (α), or group (β) with a divalent heteroatom-containing group. The divalent heteroatom-containing group and the monovalent heteroatom-containing group are represented by R in formula (3-1) above. 4 Examples include those similar to those exemplified when describing monovalent organic groups with 1 to 20 carbon atoms.

[0165] The skeletal structure (Y) preferably contains only aliphatic hydrocarbon ring structures, aromatic hydrocarbon ring structures, aromatic heterocyclic ring structures, or combinations thereof as ring structures. In other words, the skeletal structure (Y) does not contain any ring structures other than aliphatic hydrocarbon ring structures, aromatic hydrocarbon ring structures, aromatic heterocyclic ring structures, or combinations thereof. "Combinations thereof" includes not only cases where two or more ring structures are directly linked, but also cases where they are linked via divalent linking groups, as described later.

[0166] As an aliphatic hydrocarbon ring structure, R in formula (1) above2 Examples of aliphatic hydrocarbon ring structures with 3 to 30 member numbers that give the property include those similar to those exemplified. Among these, monocyclic saturated alicyclic structures, polycyclic saturated alicyclic structures, or polycyclic unsaturated alicyclic structures are preferred, and cyclohexane structures, adamantane structures, or norbornene structures are more preferred.

[0167] As an aromatic hydrocarbon ring structure, for example, Ar in formula (1) above 1 Examples of aromatic hydrocarbon ring structures with 6 to 30 member numbers that give the desired effect include those similar to those exemplified. Among these, benzene or naphthalene structures are preferred.

[0168] Examples of aromatic heterocyclic structures include oxygen-containing heterocyclic structures such as furan, pyran, benzofuran, and benzopyran structures; nitrogen-containing heterocyclic structures such as pyridine, pyrimidine, and indole structures; and sulfur-containing heterocyclic structures such as thiophene and dibenzothiophene structures. Among these, oxygen-containing heterocyclic structures or sulfur-containing heterocyclic structures are preferred, and benzofuran or dibenzothiophene structures are more preferred.

[0169] Some or all of the hydrogen atoms bonded to the atoms constituting the above ring structure may be substituted with substituents. Examples of substituents include monovalent heteroatom-containing groups and monovalent organic groups having 1 to 20 carbon atoms. Monovalent heteroatom-containing groups and monovalent organic groups having 1 to 20 carbon atoms are R in formula (3-1) above. 4 It is explained in [the relevant section].

[0170] Preferred substituents include halogen atoms, hydroxyl groups, monovalent hydrocarbon groups having 1 to 20 carbon atoms, groups (α) containing a divalent heteroatom-containing group between the carbon-carbon bonds of a monovalent hydrocarbon group having 1 to 20 carbon atoms, or groups (γ) combining a monovalent hydrocarbon group having 1 to 20 carbon atoms and a divalent heteroatom-containing group. More preferred substituents include fluorine atoms, iodine atoms, hydroxyl groups, alkyl groups, alkoxy groups, alkoxyalkyloxy groups, or groups combining a monovalent hydrocarbon group having 1 to 20 carbon atoms with a carbonyloxy group or oxycarbonyl group.

[0171] The skeleton structure (Y) preferably further has a divalent linear hydrocarbon group having 1 to 10 carbon atoms, or a group obtained by substituting some or all of the hydrogen atoms of the linear hydrocarbon group with fluorine atoms (hereinafter also referred to as "fluorinated linear hydrocarbon group"). Further, the linear hydrocarbon group or the fluorinated linear hydrocarbon group is preferably bonded to the anionic group.

[0172] In the basic skeleton (Y), the cyclic structure and the linear hydrocarbon group or the fluorinated linear hydrocarbon group may be directly bonded, or may be bonded via a divalent linking group.

[0173] Examples of the divalent linking group include a carbonyl group, an ether group, a sulfide group, an alkanediyl group having 1 to 10 carbon atoms, or a group obtained by combining these groups.

[0174] Examples of the basic skeleton (Y) include an (n+1)-valent group represented by the following formula (Y-1).

[0175]

Chemical Formula

[0176] In the above formula (Y-1), R A1 is a group obtained by removing (n+b+1) hydrogen atoms from a cyclic structure other than a cyclic acetal structure. a is 0 or 1. R A2 is a halogen atom, a hydroxy group, a carboxy group, a cyano group, a nitro group, or a monovalent organic group having 1 to 10 carbon atoms. b is an integer of 0 to 5. When a is 0, b is also 0. When b is 2 or more, a plurality of R A2 are the same or different from each other. L A1 and L A2 are each a single bond or a divalent linking group. n is the same as n in the above formula (2). R A3 and R A4Each of these is independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. c is an integer from 1 to 10. If c is 2 or more, multiple R A3 They are either identical or different from each other, and multiple R A4 They are either the same or different from each other. *1 is L in equation (2) above. 1 This is the bonding site with. *2 is A in formula (2) above. - This is the junction site.

[0177] R A1 Other ring structures that give the desired result include, for example, the aliphatic hydrocarbon ring structure, aromatic hydrocarbon ring structure, and aromatic heterocyclic structure mentioned above, as well as aliphatic heterocyclic structures other than cyclic acetals or combinations thereof. Among these, adamantane structures or benzene structures are preferred.

[0178] When a is 0, the basic skeleton (Y) does not contain a ring structure and takes on a chain structure.

[0179] R A2 Iodine atoms are preferred as such.

[0180] For b, 0 to 2 is preferable.

[0181] L A1 and L A2 Preferred components include single bonds, ether groups, or carbonyloxy groups.

[0182] For c, 1 to 3 are preferred, and 1 or 2 are more preferred.

[0183] -(C(R A3 )(R A4 )) cThe group represented by - is preferably a difluoromethyldiyl group, an ethane-1,2-diyl group, a 1-fluoroethane-1,2-diyl group, a 1,1-difluoroethane-1,2-diyl group, a 1,1-difluoro-2,2-dimethylethane-1,2-diyl group, or a 1,1-difluoro-2-isopropylethane-1,2-diyl group.

[0184] (Anionic group) The anionic group is a group bonded to the above-described skeletal structure (Y). A monovalent organic acid anionic group is preferred as the anionic group, specifically a sulfonate group (-SO3 - ) or carboxylate group (-COO - ) is preferable.

[0185] As described above, depending on the type of anionic group, the [Z] compound functions in composition (I) as a radiation-sensitive acid generator or an acid diffusion control agent (quencher).

[0186] When the anionic group is a sulfonate group, the [Z] compound functions as a radiation-sensitive acid generator in composition (I). In this case, it is preferable that composition (I) contains a [C] acid diffusion control agent. In this case, composition (I) may also contain an acid generator other than the [Z] compound ([B] acid generator).

[0187] When the anionic group is a carboxylate group, the [Z] compound functions as an acid diffusion control agent in composition (I). In this case, it is preferable that composition (I) contains the [B] acid generator. Alternatively, in this case, composition (I) may also contain an acid diffusion control agent other than the [Z] compound ([C] acid diffusion control agent).

[0188] When the anionic group is a sulfonate group, the anionic part can be represented by the substructures shown in the following formulas (A-1-1) to (A-1-3) (hereinafter also referred to as "anionic part (A-1-1) to (A-1-3)").

[0189] [ka]

[0190] When the anionic group is a carboxylate group, the anionic part can be represented by the substructures shown in the following formulas (A-2-1) to (A-2-4) (hereinafter also referred to as "anionic part (A-2-1) to (A-2-4)").

[0191] [ka]

[0192] [Cation Section] X + Examples of monovalent radiosensitive onium cations represented by the formulas (ra) to (rc) below include monovalent cations (hereinafter also referred to as "cations (ra) to (rc)").

[0193] [ka]

[0194] In the above formula (ra), R B1 and R B2 Each of these is independently a group obtained by removing one hydrogen atom from a substituted or unsubstituted aromatic hydrocarbon ring structure with 6 to 20 ring members, or R B1 and R B2 They can be combined with each other and, together with the sulfur atoms to which they are bonded, form a polycyclic aromatic ring structure with 9 to 30 member rings, either substituted or unsubstituted. B3 R is a monovalent organic group, hydroxyl group, nitro group, or halogen atom having 1 to 20 carbon atoms. b1 is an integer from 0 to 9. If b1 is 2 or more, multiple R B3 They are either identical or different from each other. b1 This is an integer between 0 and 3.

[0195] In the above formula (rb), R B4 and R B5Each of these is independently a monovalent organic group, hydroxyl group, nitro group, or halogen atom having 1 to 20 carbon atoms. b2 is an integer from 0 to 9. If b2 is 2 or more, multiple R B4 They are either identical or different from each other. b3 is an integer between 0 and 10. If b3 is 2 or greater, multiple R B5 These are either identical or different from each other. They are monovalent organic groups, hydroxyl groups, nitro groups, or halogen atoms having 1 to 20 carbon atoms. B6 This refers to a single bond or a divalent organic group having 1 to 20 carbon atoms. b2 n is an integer between 0 and 2. b3 This is an integer between 0 and 3.

[0196] In the above formula (rc), R B7 and R B8 Each of these is independently a monovalent organic group, hydroxyl group, nitro group, or halogen atom having 1 to 20 carbon atoms. b4 is an integer from 0 to 5. If b4 is 2 or more, multiple R B7 They are either identical or different from each other. b5 is an integer between 0 and 5. If b5 is 2 or greater, multiple R B8 They are either identical or different from one another.

[0197] R B1 and R B2 If is a group obtained by removing one hydrogen atom from an aromatic hydrocarbon ring structure with 6 to 20 members, whether substituted or unsubstituted, the aromatic hydrocarbon ring structure may be, for example, Ar in formula (1) above. 1 Examples of aromatic hydrocarbon ring structures with 6 to 30 member numbers that give the desired result include those with 6 to 20 member numbers. Among these, the benzene structure is preferred.

[0198] R B1 and R B2 When these elements are combined with each other and form a polycyclic aromatic ring structure with 9 to 30 member atoms, examples of such polycyclic aromatic ring structures include benzothiophene structures, dibenzothiophene structures, thioxanthene structures, thioxanthone structures, or phenoxatiin structures. Among these, the dibenzothiophene structure is preferred.

[0199] Some or all of the hydrogen atoms bonded to the atoms constituting the above aromatic hydrocarbon ring or polycyclic aromatic ring structure may be substituted with substituents. Examples of substituents include R in formula (1) above. 1 Substituents that may be present in the aliphatic hydrocarbon ring structure that gives the property are similar to those exemplified. Among these, fluorine atoms, alkyl groups, or fluorinated alkyl groups are preferred, fluorine atoms, methyl groups, tert-butyl groups, or trifluoromethyl groups are more preferred, and fluorine atoms or trifluoromethyl groups are even more preferred.

[0200] R B3 , R B4 , R B5 , R B7 and R B8 Examples of monovalent organic groups having 1 to 20 carbon atoms represented by the above formula (3-1) include R 4 Examples of monovalent organic groups with 1 to 20 carbon atoms, as represented by the formula, include groups similar to those exemplified above.

[0201] R B3 , R B4 , R B5 , R B7 and R B8 The preferred elements are a fluorine atom, an alkyl group, or a fluorinated alkyl group; more preferably a fluorine atom, a methyl group, a tert-butyl group, or a trifluoromethyl group; and even more preferably a fluorine atom or a trifluoromethyl group.

[0202] For b1, 0 to 3 is preferred, and 0 to 2 is more preferred. b1 0 or 1 is preferred. b1 is 1 or more, n b1 If is 0, then at least one R B3 It is preferable that the atom is bonded in a para position relative to the sulfur atom.

[0203] For b2, 0 to 3 is preferred, and 0 to 2 is more preferred. b2 0 or 1 is preferred. b2 is 1 or more, n b2 If is 0, then at least one R B4It is preferable that the atom is bonded in a para position relative to the sulfur atom.

[0204] For b3, 0 to 2 is preferred, and 0 or 1 is more preferred. b3 2 or 3 is preferred.

[0205] b4 is preferably 0 to 2, and more preferably 0 or 1. If b4 is 1 or more, at least one R B7 It is preferable that the bond is in the para position relative to the iodine atom. b5 is preferably 0 to 2, more preferably 0 or 1. If b5 is 1 or more, at least one R B8 It is preferable that the atom is bonded in a para position relative to the iodine atom.

[0206] R B6 Examples of divalent organic groups represented by the above formula (3-1) include R 4 Examples include groups obtained by removing one hydrogen atom from the group exemplified as a monovalent organic group having 1 to 20 carbon atoms represented by .

[0207] R B6 A single bond is preferred.

[0208] X + As the monovalent radiation-sensitive onium cation represented by , cation (ra) or cation (rc) is preferred.

[0209] As the cation (ra), a cation represented by the following formulas (ra-1) to (ra-9) (hereinafter also referred to as "cation (ra-1) to (ra-9)") is preferred.

[0210] [ka]

[0211] As the cation (rc), a cation represented by the following formulas (rc-1) to (rc-4) (hereinafter also referred to as "cation (rc-1) to (rc-4)") is preferred. [ka]

[0212] As the [Z] compound, a compound obtained by appropriately combining the above-mentioned anionic portion and the above-mentioned cation portion can be used.

[0213] <[B] Acid Generator> [B] The acid generator is a radiation-sensitive acid generator other than the [Z] compound. The [B] acid generator is a compound that generates acid upon irradiation with radiation. When the [Z] compound contained in composition (I) functions as an acid diffusion control agent, it is preferable that composition (I) contains the [B] acid generator. In this case, the acid generated from the [B] acid generator upon irradiation with radiation causes the acid-dissociable groups (a) etc. contained in the structural unit (I) of the [A1] polymer to dissociate, generating carboxyl groups etc., and a difference in the solubility of the resist film in the developer between the exposed and unexposed areas occurs, thereby forming a resist pattern. Composition (I) may contain one or more [B] acid generators.

[0214] [B] The acid generator can be any compound that does not fall under [Z] and is used as a radiation-sensitive acid generator, and is not particularly limited. Examples of [B] acid generators include onium salt compounds, N-sulfonyloxyimide compounds, sulfonimide compounds, halogen-containing compounds, diazoketone compounds, etc. Specific examples of [B] acid generators include, for example, the compounds described in paragraphs 0080 to 0113 of Japanese Patent Publication No. 2009-134088.

[0215] [B] As the acid generator, an onium salt compound is preferred, a compound containing a radiation-sensitive onium cation and a strong acid anion is more preferred, and a compound containing a radiation-sensitive onium cation and a sulfonic acid anion is even more preferred. In other words, as the acid generator, a compound that generates a strong acid upon exposure is more preferred, and a compound that generates a sulfonic acid upon exposure is even more preferred.

[0216] Examples of radiation-sensitive onium cations include those similar to those exemplified as monovalent radiation-sensitive onium cations in the section on <[Z] compounds> above.

[0217] Examples of strong acids with anionic parts include those containing a sulfonate anion as the anionic group.

[0218] The above-mentioned anion portion preferably further has a ring structure. A ring structure with 5 or more members is preferred.

[0219] Examples of ring structures with 5 or more members include alicyclic structures with 5 or more members, aliphatic heterocyclic structures with 5 or more members, aromatic hydrocarbon ring structures with 5 or more members, aromatic heterocyclic structures with 5 or more members, or combinations thereof.

[0220] The above ring structure may have some or all of the hydrogen atoms bonded to the atoms constituting the ring structure substituted with substituents. Examples of substituents include R in formula (1) above. 2 Examples of substituents that may be present in an aliphatic hydrocarbon ring structure that gives a certain property are similar to those exemplified above.

[0221] Examples of alicyclic structures with five or more ring members include monocyclic saturated alicyclic structures such as cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, and cyclododecane; monocyclic unsaturated alicyclic structures such as cyclopentene, cyclohexene, cycloheptene, cyclooctene, and cyclodecene; polycyclic saturated alicyclic structures such as norbornane, adamantane, tricyclodecane, tetracyclododecane, and steroid structures; and polycyclic unsaturated alicyclic structures such as norbornene and tricyclodecene. A "steroid structure" refers to a structure whose basic skeleton is a stelane skeleton, which is a condensed skeleton of three six-membered rings and one four-membered ring.

[0222] Examples of aliphatic heterocyclic structures with five or more ring members include lactone structures such as hexanolactone and norbornanelactone, sultone structures such as hexanosultone and norbornanesultone, oxygen-containing heterocyclic structures such as dioxolane, oxacycloheptane, and oxanorbornane, nitrogen-containing heterocyclic structures such as azacyclohexane and diazabicyclooctane, and sulfur-containing heterocyclic structures such as thiacyclohexane and thianorbornane.

[0223] Examples of aromatic hydrocarbon ring structures with five or more members include benzene structures; condensed polycyclic aromatic hydrocarbon ring structures such as naphthalene, anthracene, fluorene, biphenylene, phenanthrene, and pyrene structures; ring-assembled aromatic hydrocarbon ring structures such as biphenyl, terphenyl, binaphthalene, and phenylnaphthalene structures; and 9,10-ethanoanthracene structures.

[0224] Examples of aromatic heterocyclic structures with five or more members include oxygen-containing heterocyclic structures such as furan, pyran, benzofuran, and benzopyran structures; nitrogen-containing heterocyclic structures such as pyridine, pyrimidine, and indole structures; and sulfur-containing heterocyclic structures such as thiophene structures.

[0225] The lower limit of the number of ring members in the above ring structure is preferably 6, more preferably 8, even more preferably 9, and particularly preferably 10. The upper limit of the number of ring members is preferably 25.

[0226] As for the ring structure with 5 or more members, an alicyclic structure or an aromatic hydrocarbon ring structure is preferred, a polycyclic saturated alicyclic structure, a benzene structure, or a 9,10-ethanoanthracene structure is more preferred, and a steroid structure, a benzene structure, or a 9,10-ethanoanthracene structure is even more preferred.

[0227] When a ring structure with 5 or more members is an aromatic hydrocarbon ring structure, it is preferable that some or all of the hydrogen atoms bonded to the carbon atoms constituting the ring structure are substituted with iodine atoms. In this case, the number of iodine substitutions is preferably 1 to 4, and more preferably 1 to 3. The aromatic hydrocarbon ring structure is preferably a benzene structure or a naphthalene structure, and more preferably a benzene structure.

[0228] As stated above, the [B] acid generator is a different compound from the [Z] compound. Therefore, it is preferable that the anionic portion does not have the aforementioned acid-dissociable group (z).

[0229] [B] As the acid generator, a compound obtained by appropriately combining the above-mentioned radiation-sensitive onium cation portion and the above-mentioned strong acid anion portion can be used.

[0230] [B] As the acid generator, compounds represented by the following formulas (B-1) to (B-6) (hereinafter also referred to as "acid generators (B-1) to (B-6)") are preferred.

[0231] [ka]

[0232] In the above equations (B-1) to (B-6), X + It is a monovalent radiation-sensitive onium cation.

[0233] If composition (I) contains an acid generator [B], the lower limit of the content of the acid generator [B] in composition (I) is preferably 1 part by mass, more preferably 2 parts by mass, and still more preferably 3 parts by mass, per 100 parts by mass of the polymer [A1]. The upper limit of the above content is preferably 30 parts by mass, more preferably 20 parts by mass, and still more preferably 10 parts by mass.

[0234] <[C] Acid diffusion control agent> The [C] acid diffusion control agent is an acid diffusion control agent other than the [Z] compound. In particular, when the [Z] compound contained in composition (I) functions as a radiation-sensitive acid generator, it is preferable that composition (I) contains the [C] acid diffusion control agent. In this case, the [C] acid diffusion control agent controls the diffusion phenomenon of the acid generated from the [Z] compound by exposure in the resist film, and has the effect of controlling undesirable chemical reactions in the unexposed areas. Composition (I) may contain one or more [C] acid diffusion control agents.

[0235] [C] Examples of acid diffusion control agents include nitrogen atom-containing compounds and compounds that are photosensitive upon exposure and generate weak acids (hereinafter also referred to as "photodecayable bases"). [C] Photodecayable bases are preferred as acid diffusion control agents.

[0236] Examples of nitrogen atom-containing compounds include amine compounds such as tripentylamine and trioctylamine, amide group-containing compounds such as formamide and N,N-dimethylacetamide, urea compounds such as urea and 1,1-dimethylurea, and nitrogen-containing heterocyclic compounds such as pyridine, N-(undecylcarbonyloxyethyl)morpholine and Nt-pentyloxycarbonyl-4-hydroxypiperidine.

[0237] Examples of photodecayable bases include compounds containing a radiation-sensitive onium cation moiety and a weak acid anion moiety. In the exposed areas, the photodecayable base generates a weak acid, increasing the solubility or insolubility of the [A1] polymer in the developer, and as a result suppressing the roughness of the surface of the exposed areas after development. On the other hand, in the unexposed areas, the anion exhibits a high acid-catching function and acts as a quencher, capturing the acid diffusing from the exposed areas. In other words, because it functions as a quencher only in the unexposed areas, the contrast of the elimination reaction of the acid-dissociable group is improved, and as a result, resolution can be improved.

[0238] Examples of the radiation-sensitive onium cation moiety include those similar to those exemplified as monovalent radiation-sensitive onium cations in the section on <[Z] compounds>.

[0239] The above example of a weak acid anionic group is a carboxylate anion (-COO - Examples include those containing )

[0240] As described above, the [C] acid diffusion control agent is a different compound from the [Z] compound. Therefore, it is preferable that the anionic portion does not have the aforementioned acid-dissociable group (z).

[0241] As the photodecayable base, a compound obtained by appropriately combining the above-mentioned radiation-sensitive onium cation moiety and the above-mentioned weak acid anionic moiety can be used.

[0242] [C]As an acid diffusion control agent, compounds represented by the following formulas (C-1) to (C-5) (hereinafter also referred to as "acid diffusion control agents (C-1) to (C-5)") are preferred.

[0243] [ka]

[0244] In the above formulas (C-1) to (C-5), X + It is a monovalent radiation-sensitive onium cation.

[0245] If composition (I) contains a [C] acid diffusion control agent, the lower limit of the [C] acid diffusion control agent content in composition (I) is preferably 1 part by mass, more preferably 2 parts by mass, per 100 parts by mass of [A1] polymer. The upper limit of the above content is preferably 10 parts by mass, more preferably 5 parts by mass.

[0246] <[D] Organic solvent> Composition (I) typically contains an organic solvent [D]. The organic solvent [D] is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the polymer and compound [A1], as well as the acid generator, the acid diffusion control agent, and any other optional components that may be present.

[0247] Examples of [D]organic solvents include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents. Composition (I) may contain one or more [D]organic solvents.

[0248] Examples of alcohol-based solvents include aliphatic monoalcohol solvents with 1 to 18 carbon atoms such as 4-methyl-2-pentanol, n-hexanol, and diacetone alcohol; alicyclic monoalcohol solvents with 3 to 18 carbon atoms such as cyclohexanol; polyhydric alcohol solvents with 2 to 18 carbon atoms such as 1,2-propylene glycol; and polyhydric alcohol partial ether solvents with 3 to 19 carbon atoms such as propylene glycol monomethyl ether.

[0249] Examples of ether-based solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether; cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; and aromatic ring-containing ether solvents such as diphenyl ether and anisole.

[0250] Examples of ketone solvents include linear ketone solvents such as acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-iso-butyl ketone, and trimethylnonanone; cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and methylcyclohexanone; and 2,4-pentanedione, acetonylacetone, and acetophenone.

[0251] Examples of amide solvents include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone, and chain-like amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0252] Examples of ester solvents include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate, lactone solvents such as γ-butyrolactone and valerolactone, polyhydric alcohol carboxylate solvents such as propylene glycol acetate, polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate, polyhydric carboxylic acid diester solvents such as diethyl oxalate, and carbonate solvents such as dimethyl carbonate and diethyl carbonate.

[0253] Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents with 5 to 12 carbon atoms, such as n-pentane and n-hexane, and aromatic hydrocarbon solvents with 6 to 16 carbon atoms, such as toluene and xylene.

[0254] [D] As organic solvents, alcohol-based solvents, ketone-based solvents, ester-based solvents or combinations thereof are preferred, more preferably aliphatic monoalcohol-based solvents having 1 to 18 carbon atoms, polyhydric alcohol partial ether-based solvents having 3 to 19 carbon atoms, cyclic ketone-based solvents, monocarboxylic acid ester-based solvents, lactone-based solvents, polyhydric alcohol partial ether carboxylate-based solvents or combinations thereof are preferred, and even more preferably diacetone alcohol, propylene glycol monomethyl ether, cyclohexanone, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate or combinations thereof are preferred.

[0255] If composition (I) contains an organic solvent [D], the lower limit of the content of the organic solvent [D] is preferably 50% by mass, more preferably 60% by mass, even more preferably 70% by mass, and particularly preferably 80% by mass, relative to the total components contained in composition (I). The upper limit of the above content is preferably 99.9% by mass, more preferably 99.5% by mass, and even more preferably 99.0% by mass.

[0256] <[F]polymer> The [F] polymer is a polymer different from the [A1] polymer, and has a higher fluorine atom content than the [A1] polymer. Generally, polymers with higher hydrophobicity than the base polymer tend to be concentrated on the surface of the resist film. Because the [F] polymer has a higher fluorine atom content than the [A1] polymer, it tends to be concentrated on the surface of the resist film due to this hydrophobic property. As a result, when composition (I) contains the [F] polymer, it is expected that the cross-sectional shape of the formed resist pattern will be good. Composition (I) may contain the [F] polymer, for example, as a surface modifier for the resist film. Composition (I) may contain one or more [F] polymers.

[0257] [F] The lower limit of the fluorine atom content of the polymer is preferably 1% by mass, more preferably 2% by mass, and still more preferably 3% by mass. The upper limit of the fluorine atom content is preferably 60% by mass, more preferably 50% by mass, and still more preferably 40% by mass. Note that the fluorine atom content of the polymer is 13 The polymer structure can be determined by measuring the ¹³C NMR spectrum, and the calculation can be performed from that structure.

[0258] The form in which fluorine atoms are contained in the [F] polymer is not particularly limited and may be bonded to either the main chain or the side chains of the [F] polymer. Preferably, the [F] polymer has structural units containing fluorine atoms (hereinafter also referred to as "structural unit (f)"). The [F] polymer may further have structural units other than the above structural unit (f). The [F] polymer may have one or more of each structural unit.

[0259] [F] The lower limit of Mw determined by GPC for the polymer is preferably 2,000, more preferably 3,000, and even more preferably 5,000. The upper limit of Mw is preferably 50,000, more preferably 20,000, and even more preferably 10,000.

[0260] [F] The upper limit of the ratio of Mw to Mn (Mw / Mn) of the polymer determined by GPC is preferably 5.0, more preferably 3.0, even more preferably 2.5, and particularly preferably 2.0. The lower limit of the above ratio is usually 1.0, and preferably 1.2.

[0261] When composition (I) contains the [F] polymer, the lower limit of the [F] polymer content is preferably 0.1 parts by mass, and more preferably 0.5 parts by mass, per 100 parts by mass of the [A1] polymer. The upper limit of the above content is preferably 10 parts by mass, and more preferably 5 parts by mass.

[0262] [F] polymers, like [A1] polymers, can be synthesized, for example, by polymerizing monomers that give each structural unit using known methods.

[0263] The following describes the various structural units of the [F] polymer.

[0264] [Structural Unit (f)] Structural unit (f) is a structural unit containing a fluorine atom. The fluorine atom content of a [F] polymer can be adjusted by adjusting the proportion of structural unit (f) in the [F] polymer. Examples of structural unit (F) include the structural unit represented by the following formula (f) (hereinafter also referred to as "structural unit (f-1)").

[0265] [ka]

[0266] In the above equation (f), R f1 L is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. f R is a single bond, an oxygen atom, a sulfur atom, -COO-, -SO2NH-, -CONH-, or -OCONH-. f2 It is a monovalent organic group having 1 to 20 carbon atoms and containing a fluorine atom.

[0267] R f1 From the viewpoint of copolymerization of the monomer that gives the structural unit (f-1), a hydrogen atom or a methyl group is preferred, and a methyl group is more preferred.

[0268] L f -COO- is preferred.

[0269] R f2 Examples of monovalent organic groups having 1 to 20 carbon atoms and a fluorine atom represented by the above formula (1) include R 1 , R 2 or R 3 Examples of monovalent organic groups with 1 to 20 carbon atoms represented by include groups in which some or all of the hydrogen atoms of the example group are replaced with fluorine atoms.

[0270] R f2 Preferably, the group is a monovalent linear hydrocarbon group having 1 to 20 carbon atoms in which some or all of the hydrogen atoms are replaced with fluorine atoms (fluorinated linear hydrocarbon group), and more preferably, a monovalent fluorinated linear hydrocarbon group having 1 to 10 carbon atoms.

[0271] [F]When the polymer has structural units (f), the lower limit of the content of structural units (f) is preferably 10 mol%, more preferably 20 mol%, and even more preferably 25 mol%, relative to the total structural units constituting the [F] polymer. The upper limit of the above content is, for example, 100 mol%.

[0272] (Other structural units) Other structural units include, for example, structural units having acid-dissociable groups.

[0273] <Other optional ingredients> Other optional components include, for example, surfactants. Composition (I) may contain one or more other optional components.

[0274] <Composition (II)> Composition (II) contains [A2] a polymer and [B] an acid generator. Composition (II) usually contains [D] an organic solvent. Composition (II) may also contain [C] an acid diffusion control agent as a preferred component. Composition (II) may also contain [F] a polymer as a preferred component. Composition (II) may contain other optional components as long as they do not impair the effects of the present invention.

[0275] Composition (II) contains the [A2] polymer and the [B] acid generator, resulting in excellent sensitivity, CDU performance, and development defect suppression. The reason why composition (II) achieves the above effects through the above configuration is not entirely clear, but it can be inferred, for example, as follows: The [A2] polymer has the above-mentioned structural unit (I) and structural unit (IIa), which improves its solubility or insolubility in the developer in the exposed area. As a result, composition (II) is thought to have excellent sensitivity, CDU performance, and development defect suppression.

[0276] [A2] polymers are polymers having the structural units (I) and (IIa) described above. In other words, [A2] polymers are included in [A1] polymers, and among [A1] polymers, those having structural unit (IIa) are [A2] polymers. Therefore, for parts of [A2] polymers that are common with [A1] polymers, the description in the section on <[A1] polymers> above shall be applied.

[0277] Furthermore, the [B] acid generator and [D] organic solvent, as well as the [C] acid diffusion control agent and other optional components contained in composition (II), shall be as described in section <Composition (I)> above.

[0278] <Method for forming a resist pattern> The resist pattern formation method comprises a step of coating a radiation-sensitive resin composition directly or indirectly onto a substrate (hereinafter also referred to as the "coating step"), a step of exposing the resist film formed by the coating step (hereinafter also referred to as the "exposure step"), and a step of developing the exposed resist film (hereinafter also referred to as the "development step").

[0279] In the above coating process, composition (I) or composition (II) is used as the radiation-sensitive resin composition. Therefore, according to this resist pattern formation method, a resist pattern can be formed that has good sensitivity, excellent CDU, and suppresses the occurrence of development defects.

[0280] The following describes each step of the resist pattern formation method.

[0281] [Coating Process] In this process, a radiation-sensitive resin composition is applied to the substrate directly or indirectly. This forms a resist film on the substrate, either directly or indirectly.

[0282] In this process, composition (I) or composition (II) described above is used as the radiation-sensitive resin composition.

[0283] Examples of substrates include conventionally known materials such as silicon wafers, silicon dioxide wafers, and aluminum-coated wafers. Furthermore, indirect application of the radiation-sensitive resin composition to the substrate can be in the form of application to an anti-reflective film formed on the substrate. Examples of such anti-reflective films include organic or inorganic anti-reflective films disclosed in Japanese Patent Publication No. 6-12452 and Japanese Patent Publication No. 59-93448.

[0284] Examples of coating methods include rotary coating (spin coating), casting coating, and roll coating. After coating, pre-baking (hereinafter also referred to as "PB") may be performed as needed to volatilize the solvent in the coating film. The lower limit of the PB temperature is preferably 60°C, and more preferably 80°C. The upper limit of the above temperature is preferably 150°C, and more preferably 140°C. The lower limit of the PB time is preferably 5 seconds, and more preferably 10 seconds. The upper limit of the above time is preferably 600 seconds, and more preferably 300 seconds. The lower limit of the average thickness of the formed resist film is preferably 10 nm, and more preferably 20 nm. The upper limit of the above average thickness is preferably 1,000 nm, and more preferably 500 nm.

[0285] [Synthesis process] In this step, the resist film formed by the above coating step is exposed. This exposure is performed by irradiating exposure light through a photomask (and, in some cases, through an immersion medium such as water). The exposure light can be electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet (EUV), X-rays, and gamma rays, depending on the line width of the desired pattern; or charged particle beams such as electron beams and alpha rays. Among these, far ultraviolet light, EUV, or electron beams are preferred, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), EUV (wavelength 13.5 nm), or electron beams are more preferred, KrF excimer laser light, EUV, or electron beams are even more preferred, and EUV or electron beams are particularly preferred.

[0286] After the exposure described above, it is preferable to perform a post-exposure bake (hereinafter also referred to as "PEB") to promote the dissociation of acid-dissociable groups of the polymer, etc., by the acid generated from the acid generator, etc., by exposure in the exposed portion of the resist film. This PEB can increase the difference in solubility in the developer between the exposed and unexposed portions. The lower limit of the PEB temperature is preferably 50°C, more preferably 80°C, and even more preferably 100°C. The upper limit of the temperature is preferably 180°C, and more preferably 130°C. The lower limit of the PEB time is preferably 5 seconds, more preferably 10 seconds, and even more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, more preferably 300 seconds, and even more preferably 100 seconds.

[0287] [Development process] In this step, the exposed resist film is developed. This allows for the formation of a predetermined resist pattern. After development, it is common to wash the film with a rinsing solution such as water or alcohol and then dry it. The development method in the development step may be alkaline development or organic solvent development.

[0288] In the case of alkaline development, examples of developer solutions used for development include alkaline aqueous solutions containing at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (hereinafter also referred to as "TMAH"), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene. Among these, aqueous TMAH solutions are preferred, and 2.38% by mass aqueous TMAH solutions are more preferred.

[0289] In the case of organic solvent development, the developer can be an organic solvent such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, or alcohol solvents, or a solution containing the above organic solvents. Examples of the above organic solvents include the solvents exemplified as the [D] organic solvent in the above-mentioned radiation-sensitive resin composition. Among these, ester solvents or ketone solvents are preferred. As for ester solvents, ester acetate solvents are preferred, and n-butyl acetate is more preferred. As for ketone solvents, chain ketones are preferred, and 2-heptanone is more preferred. The lower limit of the content of organic solvents in the developer is preferably 80% by mass, more preferably 90% by mass, even more preferably 95% by mass, and particularly preferably 99% by mass. Examples of components other than organic solvents in the developer include water and silicone oil.

[0290] Examples of development methods include immersing the substrate in a tank filled with developer solution for a certain period of time (dip method), developing by piling up the developer solution on the substrate surface using surface tension and letting it remain still for a certain period of time (paddle method), spraying the developer solution onto the substrate surface (spray method), and continuously dispensing the developer solution while scanning a developer solution dispensing nozzle at a constant speed onto a substrate rotating at a constant speed (dynamic dispensing method).

[0291] Examples of patterns formed by this resist pattern formation method include line-and-space patterns and hole patterns.

[0292] <polymer> The polymer in question is described as the [A2] polymer in composition (II) above. This polymer can be suitably used as a component of a radiation-sensitive resin composition. [Examples]

[0293] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. The methods for measuring each physical property are shown below.

[0294] [Weight-average molecular weight (Mw), number-average molecular weight (Mn), and polydispersity (Mw / Mn)] The Mw and Mn of the polymer were measured according to the conditions described in the section [Measurement Method for Mw and Mn] above. The polydispersity (Mw / Mn) of the polymer was calculated from the measured Mw and Mn results.

[0295] <[A] Synthesis of polymers> [Synthesis Example] Synthesis of polymers (P-1) to (P-7) Each monomer was combined and copolymerized under tetrahydrofuran (THF) solvent, and crystallized in methanol. After repeated washing with hexane, the polymers were isolated and dried to obtain polymers represented by the following formulas (P-1) to (P-7) (hereinafter also referred to as "polymers (P-1) to (P-7)"). The composition of the obtained [A] polymer was 1 The measurements were performed by 1H-NMR. In formulas (P-1) to (P-7) below, the numerical values ​​indicated in the lower right corner of each structural unit represent the molar ratio of each structural unit to the total structural units constituting the polymer [A].

[0296] The Mw and Mw / Mn values ​​for polymers (P-1) to (P-7) were as follows. P-1: Mw=8,100, Mw / Mn=1.7 P-2: Mw=8,300, Mw / Mn=1.7 P-3: Mw=8,200, Mw / Mn=1.7 P-4: Mw=8,600, Mw / Mn=1.7 P-5: Mw=9,700, Mw / Mn=1.7 P-6: Mw=8,300, Mw / Mn=1.6 P-7: Mw=9,200, Mw / Mn=1.7

[0297] [ka]

[0298] <Preparation of radiation-sensitive resin composition> The following are the [B] acid generator, [C] acid diffusion control agent, [D] organic solvent, and [F] polymer used in the preparation of the radiation-sensitive resin composition. In the following examples and comparative examples, unless otherwise specified, "parts by mass" refers to the value when the mass of the [A] polymer used is 100 parts by mass.

[0299] [[B] Acid Generator] [B] Compounds represented by the following formulas (PAG1) to (PAG9) (hereinafter also referred to as "acid generators (PAG1) to (PAG9)") were used as acid generators. Acid generators (PAG7) to (PAG9) correspond to [Z] compounds.

[0300] [ka]

[0301] [[C] Acid diffusion control agent] [C] Compounds represented by the following formulas (Q-1) to (Q-10) (hereinafter also referred to as "acid diffusion control agents (Q-1) to (Q-10)") were used as acid diffusion control agents. Acid diffusion control agents (Q-6), (Q-7), (Q-9), and (Q-10) correspond to [Z] compounds.

[0302] [ka]

[0303] [[D] Organic solvents] [D] The following organic solvents were used as organic solvents. PGMEA: Propylene glycol monomethyl ether acetate GBL: γ-Butyrolactone CHN: Cyclohexane PGME: Propylene glycol monomethyl ether DAA: Diacetone alcohol EL: Ethyl lactate

[0304] [[F]polymer] As the [F] polymer, the polymer represented by the following formula (F-1) (hereinafter also referred to as "polymer (F-1)") was used. In the following formula (F-1), the numerical value written in the lower right of each structural unit indicates the content ratio (molar ratio) of the structural unit relative to the total structural units constituting the [F] polymer. The Mw and Mw / Mn of polymer (F-1) were as follows. F-1: Mw=8,900, Mw / Mn=2.0

[0305] [ka]

[0306] [Examples 1-14 and Comparative Examples 1-4] After dissolving 100 ppm of surfactant (3M's "FC-4430") in the organic solvent [D] listed in Table 1 below, each component shown in Table 1 below was dissolved. The resulting mixture was filtered through a 0.2 μm pore size filter to prepare a radiation-sensitive resin composition.

[0307] <Rating> The sensitivity, CDU performance, and development defect suppression properties of the radiation-sensitive resin composition prepared above were evaluated according to the following method. The evaluation results are shown in Table 1 below.

[0308] [sensitivity] On a 12-inch silicon wafer, a base layer anti-reflective coating composition (Brewer Science's "ARC66") was applied using a spin coater (Tokyo Electron Limited's "CLEAN TRACK ACT12"), and then heated at 205°C for 60 seconds to form a base layer anti-reflective coating with an average thickness of 105 nm. On this base layer anti-reflective coating, each of the prepared radiation-sensitive resin compositions was applied using the same spin coater, and pre-bake (PB) was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 55 nm was formed by cooling at 23°C for 30 seconds. This resist film was exposed using an EUV scanner (ASML's "NXE3300", NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer dimension pitch 46 nm, +20% bias hole pattern mask). Post-exposure baking (PEB) was performed on a 120°C hot plate for 60 seconds, followed by development with a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds to form a resist pattern with 23 nm holes and a 46 nm pitch. The optimal exposure amount (Eop [mJ / cm²]) for forming this 23 nm hole, 46 nm pitch resist pattern was determined. 2 ]) was used. Sensitivity is better when the Eop value is small.

[0309] [CDU performance] The Eop exposure dose determined above was applied, and a resist pattern with 23 nm holes and a 46 nm pitch was formed by the same procedure as above. The formed resist pattern was observed from the top using a scanning electron microscope (Hitachi High-Tech Corporation's "CG-5000"). The hole diameter was measured at 16 points in the 500 nm range, and the average value was calculated. In addition, the average value was measured at a total of 500 points at arbitrary points. The 3-sigma value was calculated from the distribution of the measured values, and the calculated 3-sigma value was defined as CDU (unit: nm). CDU performance indicates that the smaller the CDU value, the smaller the variation in hole diameter over long periods, and therefore the better the performance.

[0310] [Development defect suppression] On a 12-inch silicon wafer, the above-mentioned anti-reflective coating composition was applied using the above-mentioned spin coater, and then heated at 205°C for 60 seconds to form an anti-reflective coating with an average thickness of 105 nm. On this anti-reflective coating, each of the prepared radiation-sensitive resin compositions was coated using the above-mentioned spin coater, and PB was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 55 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using the above-mentioned EUV lithography apparatus (ASML's "NXE3300") with NA=0.33, illumination conditions: Conventional s=0.89, and mask: imecDEFECT32FFR02. After exposure, PEB was performed at 120°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38 mass% TMAH aqueous solution as the alkaline developer. After development, the wafers were washed with water and then dried to form a positive-type resist pattern (32nm line and space pattern), which was then used as a wafer for defect inspection. The number of defects on this wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). The number of defects after development was evaluated as follows: if the number of defects determined to be originating from the resist film was 15 or less, it was rated as "A" (excellent); if it was between 15 and 40, it was rated as "B" (good); and if it was more than 40, it was rated as "C" (poor).

[0311] [Table 1]

Claims

1. A polymer having a first structural unit represented by the following formula (1) and a second structural unit represented by the following formula (3-1), wherein its solubility in a developer changes upon the action of an acid, The compound represented by the following formula (2) and A radiation-sensitive resin composition containing [a specific substance]. 【Chemistry 1】 (In formula (1), R １ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ２ Ar is a group obtained by removing two hydrogen atoms bonded to one carbon atom from a substituted or unsubstituted aliphatic hydrocarbon ring structure with 3 to 30 members. １ (This refers to a group obtained by removing one hydrogen atom from a substituted or unsubstituted aromatic hydrocarbon ring structure with 6 to 30 members.) 【Chemistry 4】 (In formula (3-1), R 3 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L 2 is a single bond, -COO-, -O-, or -CONH-. Ar 2 is a group obtained by removing (s + t + 1) hydrogen atoms from an aromatic hydrocarbon ring structure with 6 to 30 members. s is an integer from 1 to 3. When s is 1, the hydroxyl group is bonded to a carbon atom adjacent to the carbon atom bonded to L 2 among the carbon atoms constituting Ar 2. When s is 2 or more, at least one hydroxyl group is bonded to a carbon atom adjacent to the carbon atom bonded to L 2 among the carbon atoms constituting Ar 2. t is an integer from 0 to 8. When t is 1, R 4 is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. When t is 2 or more, multiple R 4s are identical or different from each other, and are either halogen atoms or monovalent organic groups having 1 to 20 carbon atoms, or multiple R 4s Two or more of these can be combined with each other to form an alicyclic structure with 4 to 20 members, along with the carbon chain to which they are bonded. 【Chemistry 2】 (In formula (2), Z is an acid-dissociable group. L １ is *-O-CO- or -O-. * indicates the bonding site with Z. Y is an (n+1) valence group represented by the following formula (Y-1). A － is a monovalent anionic group. n is an integer from 1 to 5. If n is 2 or greater, then 2 or more Zs are either the same or different from each other, and 2 or more Ls are the same. １ They are either identical or different from each other. ＋ (This is a monovalent, radiation-sensitive onium cation.) 【Transformation 3】 (In formula (Y-1), R Ａ１ is a group obtained by removing (n+b+1) hydrogen atoms from a ring structure other than a cyclic acetal structure. a is 1. R Ａ２ is a halogen atom, a hydroxy group, a carboxy group, a cyano group, a nitro group or a monovalent organic group having 1 to 10 carbon atoms. b is an integer of 0 to 5. When b is 2 or more, plural R Ａ２ are the same or different from each other. L Ａ１ and L Ａ２ are each a single bond or a divalent linking group. n is the same as n in the above formula (2). R Ａ３ and R Ａ４ are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. c is an integer of 1 to 10. When c is 2 or more, plural R Ａ３ are the same or different from each other, and plural R Ａ４ are the same or different from each other. *1 is a bonding site to L １ in the above formula (2). *2 is a bonding site to A － in the above formula (2).)

2. A in formula (2) above － However, SO ３ － or COO － The radiation-sensitive resin composition according to claim 1.

3. In the above formula (Y-1), R Ａ１ The radiation-sensitive resin composition according to claim 1 or claim 2, wherein the ring structure other than the cyclic acetal structure that gives is an aliphatic hydrocarbon ring structure, an aromatic hydrocarbon ring structure, an aromatic heterocyclic structure, an aliphatic heterocyclic structure other than a cyclic acetal, or a combination thereof.

4. A polymer having a first structural unit represented by the following formula (1) and a third structural unit represented by the following formula (3-2), wherein its solubility in a developer changes upon the action of an acid, Radiation-sensitive acid generator and A radiation-sensitive resin composition containing [a specific substance]. 【Transformation 5】 (In formula (1), R １ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ２ Ar is a group obtained by removing two hydrogen atoms bonded to one carbon atom from a substituted or unsubstituted aliphatic hydrocarbon ring structure with 3 to 30 members. １ (This refers to a group obtained by removing one hydrogen atom from a substituted or unsubstituted aromatic hydrocarbon ring structure with 6 to 30 members.) 【Transformation 6】 (In formula (3-2), R ３ L is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ２ It is a single bond. Ar ２ This is a group obtained by removing (s + t + 1) hydrogen atoms from an aromatic hydrocarbon ring structure with 6 to 30 ring members. s is an integer from 1 to 3. When s is 1, the hydroxyl group is Ar ２ Among the carbon atoms that make up the L ２ It bonds to a carbon atom adjacent to the carbon atom it bonds to. If s is 2 or more, at least one hydroxyl group is Ar ２ Among the carbon atoms that make up the L ２ It bonds to a carbon atom adjacent to the carbon atom it bonds to. t is an integer from 0 to 8. When t is 1, R ４ is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. When t is 2 or more, multiple R ４ These are either identical or different, and are halogen atoms or monovalent organic groups having 1 to 20 carbon atoms, or multiple R ４ Two or more of these can be combined with each other to form an alicyclic structure with 4 to 20 members, along with the carbon chain to which they are bonded.

5. A step of coating a substrate directly or indirectly with the radiation-sensitive resin composition described in any one of claims 1 to 4, A step of exposing the resist film formed by the above coating, The process of developing the exposed resist film described above A resist pattern formation method comprising the following:

6. A polymer having a first structural unit represented by the following formula (1) and a third structural unit represented by the following formula (3-2). 【Transformation 7】 (In formula (1), R １ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ２ Ar is a group obtained by removing two hydrogen atoms bonded to one carbon atom from a substituted or unsubstituted aliphatic hydrocarbon ring structure with 3 to 30 members. １ (This refers to a group obtained by removing one hydrogen atom from a substituted or unsubstituted aromatic hydrocarbon ring structure with 6 to 30 members.) 【Transformation 8】 (In formula (3-2), R ３ L is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ２ It is a single bond. Ar ２ This is a group obtained by removing (s + t + 1) hydrogen atoms from an aromatic hydrocarbon ring structure with 6 to 30 ring members. s is an integer from 1 to 3. When s is 1, the hydroxyl group is Ar ２ Among the carbon atoms that make up the L ２ It bonds to a carbon atom adjacent to the carbon atom it bonds to. If s is 2 or more, at least one hydroxyl group is Ar ２ Among the carbon atoms that make up the L ２ It bonds to a carbon atom adjacent to the carbon atom it bonds to. t is an integer from 0 to 8. When t is 1, R ４ is a halogen atom or a monovalent organic group having 1 to 10 carbon atoms. When t is 2 or more, multiple R ４ These are either identical or different, and are halogen atoms or monovalent organic groups having 1 to 10 carbon atoms, or multiple R ４ Two or more of these can be combined with each other to form an alicyclic structure with 4 to 20 members, along with the carbon chain to which they are bonded.

Images