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

Abstract

The purpose of the present invention is to provide a radiation-sensitive resin composition and a resist pattern formation method, which enable formation of a resist pattern having excellent LWR performance and CDU performance and having good sensitivity to exposure light. A radiation-sensitive resin composition containing a compound represented by formula (1) and a polymer having a structural unit that includes an acid-dissociable group.

Description

[Technical field]

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

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

[0003] A radiation-sensitive composition is required to have good sensitivity to exposure light such as extreme ultraviolet rays and electron beams, as well as excellent CDU (Critical Dimension Uniformity) performance and LWR (Line Width Roughness) performance.

[0004] In response to these demands, the types and molecular structures of polymers, acid generators and other components used in radiation-sensitive resin compositions have been investigated, and combinations of these have also been investigated in detail (see JP2010-134279A, JP2014-224984A, and JP2016-047815A). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-134279 A [Patent Document 2] JP 2014-224984 A [Patent Document 3] JP 2016-047815 A Summary of the Invention [Problem to be solved by the invention]

[0006] At present, resist patterns have been miniaturized to a level of line width of 40 nm or less, and the above-mentioned performance requirements are becoming higher and higher, but the above-mentioned conventional radiation-sensitive resin compositions are unable to satisfy these requirements.

[0007] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a radiation-sensitive resin composition and a method for forming a resist pattern that have good sensitivity to exposure light and are capable of forming a resist pattern that has excellent CDU performance and LWR performance. [Means for solving the problem]

[0008] The invention made to solve the above-mentioned problems relates to a radiation-sensitive resin composition containing a polymer having a structural unit containing an acid-dissociable group (hereinafter also referred to as “polymer [A]”) and a compound represented by the following formula (1) (hereinafter also referred to as “compound [B]”). [ka] (In formula (1), R 1 , R 2 and R 3 are each independently a monovalent organic group having 1 to 20 carbon atoms, a halogen atom, a hydroxyl group, or a nitro group. a is an integer of 0 to 7. When a is 2 or more, multiple R 1 are the same or different. b is an integer of 0 to 4. When b is 2 or more, multiple R 2 are the same or different. c is an integer of 0 to 4. When c is 2 or more, multiple R 3 are the same or different. X 1 , X 2 and X 3 are each independently a group represented by the following formula (2), and d is an integer of 0 to 7. When d is 2 or more, a plurality of X 1 are the same or different. e is an integer of 0 to 4. When e is 2 or more, a plurality of X2 are the same or different. f is an integer of 0 to 4. When f is 2 or more, a plurality of X 3 are the same or different from each other, provided that d+e+f is 1 or more, a+d is 7 or less, b+e is 4 or less, and c+f is 4 or less. R 4 is a (b+e+1)-valent hydrocarbon group having 1 to 20 carbon atoms, and R 5 is a (c+f+1)-valent hydrocarbon group having 1 to 20 carbon atoms, or R 4 and R 5 and represent a part of a heterocyclic structure having 4 to 20 ring members formed by combining with each other and the sulfur atom to which they are bonded. n is 0 or 1. - is a monovalent sulfonate anion. [ka] In formula (2), L is an organic group having 1 to 20 carbon atoms and a valence of (m+1). Y is -COO-, -OCO- or -N(R 7 )CO-. R 7 R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. 6 is a monovalent organic group having 1 to 20 carbon atoms. m is an integer of 1 to 5. When m is 2 or more, multiple Y's may be the same or different, and multiple R 6 are the same or different. * indicates a bonding site to a portion other than the group represented by formula (2) in the compound.)

[0009] Another invention made to solve the above-mentioned problems is a method for forming a resist pattern, comprising the steps of: applying the above-mentioned radiation-sensitive resin composition directly or indirectly onto a substrate; exposing the resist film formed by the applying step; and developing the exposed resist film.

[0010] Yet another invention made to solve the above problems is a compound represented by the above formula (1). Effect of the Invention

[0011] According to the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention, a resist pattern having good sensitivity to exposure light and excellent CDU performance and LWR performance can be formed. The compound of the present invention can be suitably used as a component of the composition. Therefore, the radiation-sensitive resin composition, the method for forming a resist pattern, and the compound can be suitably used in the processing of semiconductor devices, which are expected to become increasingly finer in the future. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The radiation-sensitive resin composition, the method for forming a resist pattern, and the compound of the present invention will be described in detail below.

[0013] <Radiation sensitive resin composition> The radiation-sensitive resin composition contains a polymer [A] and a compound [B]. The radiation-sensitive resin composition usually contains an organic solvent (hereinafter also referred to as "organic solvent [D]"). The radiation-sensitive resin composition may contain, as a suitable component, an acid diffusion controller (hereinafter also referred to as "acid diffusion controller [C]") and / or a polymer having a higher mass content of fluorine atoms than the polymer [A] (hereinafter also referred to as "polymer [E]"). The radiation-sensitive resin composition may contain other optional components within a range that does not impair the effects of the present invention.

[0014] The radiation-sensitive resin composition contains the polymer [A] and the compound [B], and thus has good sensitivity to exposure light, and can form a resist pattern having excellent CDU and LWR performance. The reason why the radiation-sensitive resin composition has the above-mentioned configuration and thus exhibits the above-mentioned effect is not necessarily clear, but can be presumed, for example, as follows. That is, the cation in the compound [B] contained in the radiation-sensitive resin composition has a group represented by the above formula (2), and thus it is possible to introduce substituents having various functions without impairing the efficiency of acid generation by exposure. As a result, it is considered that the radiation-sensitive resin composition has good sensitivity to exposure light, and can form a resist pattern having excellent CDU and LWR performance.

[0015] Each component contained in the radiation-sensitive resin composition will be described below.

[0016] <[A] Polymer> The polymer [A] has a structural unit containing an acid-dissociable group (hereinafter also referred to as "structural unit (I)"). The polymer [A] preferably further has a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof (hereinafter also referred to as "structural unit (II)"). The polymer [A] preferably further has a structural unit containing a phenolic hydroxyl group (hereinafter also referred to as "structural unit (III)"). The polymer [A] may further have other structural units (hereinafter simply referred to as "other structural units") other than the structural units (I) to (III). The polymer [A] may have one or more types of each structural unit. The radiation-sensitive resin composition may contain one or more types of the polymer [A].

[0017] Each structural unit contained in the polymer [A] will be described below.

[0018] Structural Units The structural unit (I) is a structural unit containing an acid dissociable group. The "acid dissociable group" refers to a group that substitutes a hydrogen atom in a carboxy group, a hydroxy group, or the like, and dissociates under the action of an acid to give a carboxy group, a hydroxy group, or the like. The acid dissociable group dissociates under the action of an acid generated from the compound [B] or the like upon exposure, and the solubility of the polymer [A] in the exposed area in a developer changes, thereby forming a resist pattern.

[0019] Examples of the structural unit (I) include a structural unit represented by the following formula (3) (hereinafter, also referred to as "structural unit (I-1)"). In the following formula (3), -C(R X )(R Y )(R Z ) corresponds to an acid-dissociable group.

[0020] [ka]

[0021] In the above formula (3), R T R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. Y and R Z are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or are a part of an alicyclic structure having 3 to 20 ring members constituted by combining these groups together with the carbon atoms to which these groups are bonded. 1 is a single bond or a divalent organic group having 1 to 20 carbon atoms.

[0022] In this specification, the term "carbon number" refers to the number of carbon atoms constituting a group.

[0023] In this specification, the term "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. This "hydrocarbon group" may be a saturated or unsaturated hydrocarbon group. The term "linear hydrocarbon group" refers to a hydrocarbon group that does not include a cyclic structure and is composed only of a linear structure, and includes both linear hydrocarbon groups and branched hydrocarbon groups. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes both monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic hydrocarbon groups. However, it is not necessary for the alicyclic structure to be composed only of the alicyclic structure, and it may include a linear structure as a part of the alicyclic structure. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that includes an aromatic ring structure as a ring structure. However, it is not necessary for the alicyclic structure to be composed only of the aromatic ring structure, and it may include a linear structure or an alicyclic structure as a part of the alicyclic structure.

[0024] As used herein, an "organic group" refers to a group containing at least one carbon atom.

[0025] R X , R Y or R Z Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0026] Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, and an i-propyl group, alkenyl groups such as an ethenyl group, a propenyl group, and a butenyl group, and alkynyl groups such as an ethynyl group, a propynyl group, and a butynyl group.

[0027] Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic alicyclic saturated hydrocarbon groups such as a cyclopentyl group, a cyclohexyl group, etc.; polycyclic alicyclic saturated hydrocarbon groups such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group, etc.; monocyclic alicyclic unsaturated hydrocarbon groups such as a cyclopentenyl group, a cyclohexenyl group, etc.; and polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group, a tricyclodecenyl group, a tetracyclododecenyl group, etc.

[0028] Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group, and aralkyl groups such as a benzyl group, a phenethyl group, a naphthylmethyl group, and an anthrylmethyl group.

[0029] R Y and R Z Examples of the alicyclic structure having 3 to 20 ring members constituted by combining these groups together with the carbon atoms to which they are bonded include monocyclic saturated alicyclic structures such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, and a cyclooctane structure; polycyclic saturated alicyclic structures such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure; monocyclic unsaturated alicyclic structures such as a cyclopropene structure, a cyclobutene structure, a cyclopentene structure, and a cyclohexene structure; and polycyclic unsaturated alicyclic structures such as a norbornene structure, a tricyclodecene structure, and a tetracyclododecene structure.

[0030] L 1 Examples of the divalent organic group having 1 to 20 carbon atoms represented by the formula (I) include a divalent hydrocarbon group having 1 to 20 carbon atoms, a group (α) containing a divalent heteroatom-containing group between the carbon atoms of this hydrocarbon group, a group (β) in which some or all of the hydrogen atoms in the above hydrocarbon group or the above group (α) have been substituted with a monovalent heteroatom-containing group, and a group (γ) in which the above hydrocarbon group, the above group (α) or the above group (β) is combined with a divalent heteroatom-containing group.

[0031] Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms include R X , R Y or R Z Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the following formula (I) include groups in which one hydrogen atom has been removed from the groups exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the following formula (I):

[0032] Examples of heteroatoms constituting the monovalent or divalent heteroatom-containing group include oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, silicon atoms, halogen atoms, etc. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0033] Examples of the divalent heteroatom-containing group include -O-, -CO-, -S-, -CS-, -NR'-, and combinations of two or more of these, where R' is a hydrogen atom or a monovalent hydrocarbon group.

[0034] R T From the viewpoint of copolymerizability of the monomer that gives the structural unit (I), a hydrogen atom or a methyl group is preferred.

[0035] R X As the alkyl group, a chain hydrocarbon group or an aromatic hydrocarbon group is preferable, and an alkyl group or an aryl group is more preferable.

[0036] R Y and R Z is a chain hydrocarbon group or an alicyclic hydrocarbon group, or R Y and R Z are preferably combined with each other to form a saturated alicyclic structure together with the carbon atom to which these groups are attached.

[0037] L 1 is preferably a single bond or a group consisting of a combination of a divalent hydrocarbon group and a divalent heteroatom-containing group.

[0038] As the structural unit (I-1), structural units represented by the following formulas (3-1) to (3-8) (hereinafter also referred to as "structural units (I-1-1) to (I-1-8)") are preferable.

[0039] [ka]

[0040] In the above formulas (3-1) to (3-8), R T is synonymous with the above formula (3).

[0041] The lower limit of the content of the structural unit (I) in the polymer [A] is preferably 20 mol%, more preferably 25 mol%, and even more preferably 30 mol%, based on the total structural units constituting the polymer [A]. The upper limit of the content is preferably 80 mol%, more preferably 70 mol%, and even more preferably 60 mol%. By setting the content of the structural unit (I) within the above range, the sensitivity to exposure light, CDU performance, and LWR performance of the radiation-sensitive resin composition can be further improved.

[0042] [Structural unit (II)] The structural unit (II) is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. By further having the structural unit (II), the polymer [A] can adjust its solubility in a developer more appropriately, and as a result, the sensitivity to exposure light, CDU performance, and LWR performance of the radiation-sensitive resin composition can be further improved.

[0043] Examples of the structural unit (II) include structural units represented by the following formula:

[0044] [ka]

[0045] [ka]

[0046] [ka]

[0047] [ka]

[0048] In the above formula, R L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0049] The structural unit (II) is preferably a structural unit containing a lactone structure.

[0050] When the polymer [A] has the structural unit (II), the lower limit of the content of the structural unit (II) is preferably 5 mol%, more preferably 10 mol%, and even more preferably 15 mol% based on the total structural units in the polymer [A].The upper limit of the content is preferably 70 mol%, more preferably 65 mol%, and even more preferably 60 mol%.

[0051] [Structural unit (III)] The structural unit (III) is a structural unit containing a phenolic hydroxyl group. The term "phenolic hydroxyl group" refers not only to a hydroxyl group directly bonded to a benzene ring, but also to any hydroxyl group directly bonded to an aromatic ring.

[0052] [A] The polymer further has the structural unit (III), so that the hydrophilicity of the resist film can be increased, the solubility in the developer can be appropriately adjusted, and the adhesion of the resist pattern to the substrate can be improved. In addition, when extreme ultraviolet rays (EUV) or electron beams are used as the radiation to be irradiated in the exposure step in the resist pattern forming method described below, the sensitivity to the exposure light can be further improved. Therefore, the radiation-sensitive resin composition can be suitably used as a radiation-sensitive resin composition for extreme ultraviolet exposure or electron beam exposure.

[0053] Examples of the structural unit (III) include structural units represented by the following formula:

[0054] [ka]

[0055] In the above formula, R L3 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0056] When the polymer [A] has the structural unit (III), the lower limit of the content of the structural unit (III) is preferably 20 mol %, more preferably 30 mol %, based on the total structural units in the polymer [A].The upper limit of the content is preferably 90 mol %, more preferably 80 mol %.

[0057] [Other structural units] Examples of other structural units include a structural unit containing an alcoholic hydroxyl group (hereinafter also referred to as "structural unit (IV)") and a structural unit containing an aromatic hydrocarbon group other than the above structural units (I) to (IV) (hereinafter also referred to as "structural unit (V)").

[0058] Examples of the structural unit (IV) include structural units represented by the following formula: [ka]

[0059] In the above formula, R L2 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0060] Examples of monomers which provide the structural unit (V) include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, phenyl(meth)acrylate, benzyl(meth)acrylate, 4-t-butylphenyl(meth)acrylate, acenaphthylene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1-naphthyl(meth)acrylate, 2-naphthyl(meth)acrylate, 1-naphthylmethyl(meth)acrylate, 1-anthryl(meth)acrylate, 2-anthryl(meth)acrylate, 9-anthryl(meth)acrylate, 9-anthrylmethyl(meth)acrylate, 1-vinylpyrene, and 2-vinylpyrene.

[0061] When the polymer [A] has other structural units, the lower limit of the content of the other structural units is preferably 1 mol %, more preferably 5 mol %, based on the total structural units in the polymer [A].The upper limit of the content is preferably 30 mol %, more preferably 20 mol %.

[0062] The lower limit of the weight average molecular weight (Mw) of the polymer [A] in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 2,000, more preferably 3,000, and even more preferably 4,000. The upper limit of the Mw is preferably 10,000, more preferably 9,000, and even more preferably 8,000. By setting the Mw of the polymer [A] within the above range, the solubility in the developer can be appropriately adjusted.

[0063] The upper limit of the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) of the polymer [A] measured by GPC (Mw / Mn, hereinafter also referred to as "dispersity") is preferably 2.50, more preferably 2.00, and even more preferably 1.75. The lower limit of the ratio is usually 1.00, preferably 1.10, and more preferably 1.20. By setting the Mw / Mn of the polymer [A] within the above range, the coatability of the radiation-sensitive resin composition can be further improved.

[0064] In this specification, the Mw and Mn of the polymer are values ​​measured by gel permeation chromatography (GPC) under the following conditions. GPC columns: 2 "G2000HXL", 1 "G3000HXL" and 1 "G4000HXL" from Tosoh Corporation Elution solvent: Tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100μL Column temperature: 40℃ Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0065] The lower limit of the content of the polymer [A] in the radiation-sensitive resin composition is preferably 50 mass %, more preferably 60 mass %, even more preferably 70 mass %, and particularly preferably 80 mass %, based on all components other than the organic solvent [D].

[0066] The polymer (A) can be synthesized, for example, by polymerizing monomers that provide the respective structural units by a known method.

[0067] <[B] Compound> The compound [B] is a compound represented by the following formula (1). The compound [B] is a substance that generates an acid when irradiated with radiation, and functions as a radiation-sensitive acid generator in the radiation-sensitive resin composition. The radiation-sensitive resin composition may contain one or more types of the compound [B].

[0068] Examples of the radiation include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays, and gamma rays, as well as charged particle beams such as electron beams and alpha rays. An acid dissociable group contained in the structural unit (I) of the polymer [A] is dissociated by an acid generated from the compound [B] or the like upon irradiation (exposure) with radiation to generate a carboxyl group or the like, and a difference occurs in the solubility of the polymer [A] in a developer between the exposed and unexposed areas, thereby forming a resist pattern.

[0069] The lower limit of the temperature at which the acid dissociates the acid dissociable group is preferably 80° C., more preferably 90° C., and even more preferably 100° C. The upper limit of the temperature is preferably 130° C., more preferably 120° C., and even more preferably 110° C. The lower limit of the time at which the acid dissociates the acid dissociable group is preferably 10 seconds, and more preferably 1 minute. The upper limit of the time is preferably 10 minutes, and more preferably 2 minutes.

[0070] In the following, A in the following formula (1) - The monovalent sulfonate anion represented by the following formula (1) is also referred to as the "sulfonate anion", the portion other than this sulfonate anion in the following formula (1) is also referred to as the "onium cation", and the group represented by the following formula (2) described below is also referred to as the "group (X)".

[0071] [ka]

[0072] In the above formula (1), R 1 , R 2 and R 3 are each independently a monovalent organic group having 1 to 20 carbon atoms, a halogen atom, a hydroxyl group, or a nitro group. a is an integer of 0 to 7. When a is 2 or more, multiple R 1 are the same or different. b is an integer of 0 to 4. When b is 2 or more, multiple R 2 are the same or different. c is an integer of 0 to 4. When c is 2 or more, multiple R 3 are the same or different. X 1 , X 2 and X 3 are each independently a group represented by the following formula (2) described later, and d is an integer of 0 to 7. When d is 2 or more, a plurality of X 1 are the same or different. e is an integer of 0 to 4. When e is 2 or more, a plurality of X 2 are the same or different. f is an integer of 0 to 4. When f is 2 or more, a plurality of X 3are the same or different from each other, provided that d+e+f is 1 or more, a+d is 7 or less, b+e is 4 or less, and c+f is 4 or less. R 4 is a (b+e+1)-valent hydrocarbon group having 1 to 20 carbon atoms, and R 5 is a (c+f+1)-valent hydrocarbon group having 1 to 20 carbon atoms, or R 4 and R 5 and represent a part of a heterocyclic structure having 4 to 20 ring members formed by combining with each other and the sulfur atom to which they are bonded. n is 0 or 1. - is a monovalent sulfonate anion.

[0073] R 1 , R 2 or R 3 Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the formula (I) include monovalent hydrocarbon groups having 1 to 20 carbon atoms, groups (α') containing a divalent heteroatom-containing group between the carbon atoms of this hydrocarbon group, groups (β') in which some or all of the hydrogen atoms in the above hydrocarbon group or the above group (α') have been substituted with a monovalent heteroatom-containing group, and groups (γ') in which the above hydrocarbon group, the above group (α') or the above group (β') is combined with a divalent heteroatom-containing group.

[0074] Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include R X , R Y or R Z Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms and represented by the following formula include the same groups as those exemplified above.

[0075] Examples of the heteroatom constituting the monovalent or divalent heteroatom-containing group include L 1 In the divalent organic group having 1 to 20 carbon atoms represented by the following formula, examples of the heteroatom constituting the monovalent or divalent heteroatom-containing group include the same as those exemplified above.

[0076] The divalent heteroatom-containing group is L in the above formula (3). 1In the divalent organic group having 1 to 20 carbon atoms represented by the following formula, examples of the divalent heteroatom-containing group include the same groups as those exemplified above.

[0077] a is preferably 0 to 3, more preferably 0 to 2, and still more preferably 0 or 1. b is preferably 0 to 3, more preferably 0 to 2, and still more preferably 0 or 1. c is preferably 0 to 3, more preferably 0 to 2, and still more preferably 0 or 1.

[0078] R 4 Examples of the (b+e+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (3) include R X , R Y or R Z Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the following formula (I) include groups in which (b+e) hydrogen atoms have been removed from the above-listed examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the following formula (I):

[0079] R 5 Examples of the (c+f+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (3) include R X , R Y or R Z Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the following formula (I) include groups in which (c+f) hydrogen atoms have been removed from the above-listed examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms:

[0080] R 4 and R 5 Examples of the heterocyclic structure having 4 to 20 ring members formed by combining these with the sulfur atom to which they are bonded include aliphatic heterocyclic structures such as a tetrahydrothiophene structure, and aromatic heterocyclic structures such as a dibenzothiophene structure.

[0081] R 4 or R 5 is an aromatic hydrocarbon group, or R 4 and R 5 and are preferably combined with each other to form a heterocyclic structure having 4 to 20 ring members together with the sulfur atom to which they are bonded.

[0082] d is preferably 0 to 3, and more preferably 0 to 2. e is preferably 0 to 3, and more preferably 0 to 2. f is preferably 0 to 2, and more preferably 0 to 2. d+e+f is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and further preferably 1 or 2.

[0083] As n, 0 or 1 is preferable, and 0 is more preferable.

[0084] [Group(X)] The group (X) is a group represented by the following formula (2). By having the group (X) in the compound [B], it is possible to introduce substituents having various functions without impairing the efficiency of generating acid by exposure. As a result, the radiation-sensitive resin composition has good sensitivity to exposure light, and can form a resist pattern having excellent CDU performance and LWR performance.

[0085] [ka]

[0086] In the above formula (2), L is an organic group having 1 to 20 carbon atoms and a valence of (m+1). Y is -COO-, -OCO- or -N(R 7 )CO-. R 7 R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. 6 is a monovalent organic group having 1 to 20 carbon atoms. m is an integer of 1 to 5. When m is 2 or more, multiple Y's may be the same or different, and multiple R 6 are the same or different. * indicates a bonding site to a portion of the compound [B] other than the group represented by formula (2).

[0087] Examples of the (m+1)-valent organic group having 1 to 20 carbon atoms represented by L include R 1 , R 2 or R 3 Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the following formula (I) include groups in which m hydrogen atoms have been removed from the groups exemplified above.

[0088] L is preferably a (m+1)-valent hydrocarbon group having 1 to 20 carbon atoms. Examples of the (m+1)-valent hydrocarbon group having 1 to 20 carbon atoms include R X , R Y or R Z Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms and represented by the following formula (I) include a group in which m hydrogen atoms have been removed from the group exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms and represented by the following formula (I): More specifically, a group in which m hydrogen atoms have been removed from a methyl group, a group in which m hydrogen atoms have been removed from a tert-butyl group, a group in which m hydrogen atoms have been removed from a cyclohexyl group, or a group in which m hydrogen atoms have been removed from a phenyl group is preferred, and a group in which m hydrogen atoms have been removed from a methyl group, or a group in which m hydrogen atoms have been removed from a phenyl group is more preferred.

[0089] Y is -COO- or -N(R 7 )CO- is preferable, and -COO- or -NHCO- is more preferable. 6 When the bonding site is indicated by "**", Y is -COO-**, -OCO-** or -N(R 7 )CO-**.

[0090] m is preferably an integer of 1 to 4, and more preferably an integer of 1 to 3.

[0091] R 6 Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the formula (1) include R 1 , R 2 or R 3 Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the formula R 6 By appropriately selecting a monovalent organic group having 1 to 20 carbon atoms represented by the following formula, it is possible to introduce substituents having various functions, such as an acid dissociable group, a polar group, or a halogen atom-containing group, which will be described later, without impairing the efficiency of acid generation by exposure.

[0092] R 6is preferably an acid dissociable group (hereinafter also referred to as "acid dissociable group (x)"). The "acid dissociable group (x)" refers to a group that substitutes a hydrogen atom in a carboxy group and dissociates under the action of an acid to give a carboxy group. In other words, R 6 When is an acid dissociable group (x), Y is -COO-.

[0093] Examples of the acid dissociable group (x) include a group represented by the following formula (2-1) (hereinafter also referred to as "acid dissociable group (x-1)").

[0094] [ka]

[0095] In the above formula (2-1), R 8 R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. 9 and R 10 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or these groups combined with each other to form an alicyclic structure having 3 to 20 ring members together with the carbon atoms to which these groups are bonded. *** represents the bonding site with Y in the above formula (2).

[0096] R 8 , R 9 or R 10 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (3) include R X , R Y or R Z Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms and represented by the following formula include the same groups as those exemplified above.

[0097] R 9 and R 10 Examples of the alicyclic structure having 3 to 20 ring members formed by combining these groups together with the carbon atoms to which these groups are bonded include R Y and R ZExamples of the alicyclic structure include the same structures as those exemplified as the alicyclic structure having 3 to 20 ring members formed by combining these groups together with the carbon atoms to which these groups are bonded.

[0098] R 8 As the alkyl group, a chain hydrocarbon group is preferable, and an alkyl group is more preferable.

[0099] R 9 and R 10 is a chain hydrocarbon, or R 9 and R 10 are preferably combined with each other to form a saturated alicyclic structure together with the carbon atom to which these groups are attached.

[0100] Examples of the acid-dissociable group (x-1) include groups represented by the following formulas (2-1-1) to (2-1-4).

[0101] [ka]

[0102] In the above formulas (2-1-1) to (2-1-4), *** has the same meaning as in the above formula (2-1).

[0103] R 6 Also preferred are a lactone ring group, a sultone ring group, a carbonate ring group, an alcoholic hydroxyl group-containing alicyclic hydrocarbon group, a phenolic hydroxyl group-containing group, or an amide group (hereinafter, these groups are also referred to as "polar groups"). Among these, a lactone ring group, a carbonate ring group, an alcoholic hydroxyl group-containing alicyclic hydrocarbon group, or a phenolic hydroxyl group-containing group is more preferred.

[0104] Examples of the polar group include groups represented by the following formulae (2-2-1) to (2-2-4). The group represented by the following formula (2-2-1) is a specific example of a lactone ring group, the group represented by the following formula (2-2-2) is a specific example of a carbonate ring group, the group represented by the following formula (2-2-3) is a specific example of an alcoholic hydroxyl group-containing alicyclic hydrocarbon group, and the group represented by the following formula (2-2-4) is a specific example of a phenolic hydroxyl group-containing group.

[0105] [ka]

[0106] In the above formulas (2-2-1) to (2-2-4), *** has the same meaning as in the above formula (2-1).

[0107] R 6 It is also preferable that the group is a halogen atom-containing group. Examples of the halogen atom-containing group include groups in which some or all of the hydrogen atoms in a monovalent organic group having 1 to 20 carbon atoms have been substituted with halogen atoms.

[0108] Examples of the halogen atom-containing group include groups represented by the following formulas (2-3-1) to (2-3-4).

[0109] [ka]

[0110] In the above formulas (2-3-1) to (2-3-4), *** has the same meaning as in the above formula (2-1).

[0111] As the onium cation, for example, cations represented by the following formulas (1-1) to (1-15) are preferable.

[0112] [ka]

[0113] [Sulfonate anion] A - Examples of the sulfonate anion represented by the formula (5) include a sulfonate anion represented by the formula (5) below (hereinafter, also referred to as "anion (X-1)"). [ka]

[0114] In the above formula (5), R p1 R is a monovalent group containing a ring structure having 5 or more ring members. p2 is a divalent linking group. p3 and R p4 R 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. p5 and R p6 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. p1 is an integer from 0 to 10. p2 is an integer from 0 to 10. p3 is an integer from 0 to 10. p1 +n p2 +n p3 is between 1 and 30. p1 If is 2 or more, multiple R p2 are the same or different. n p2 If is 2 or more, multiple R p3 are the same or different, and multiple R p4 are the same or different. n p3 If is 2 or more, multiple R p5 are the same or different, and multiple R p6 are the same or different from each other.

[0115] R p1 Examples of the monovalent group containing a ring structure having 5 or more ring members include a monovalent group containing an alicyclic structure having 5 or more ring members, a monovalent group containing an aliphatic heterocyclic structure having 5 or more ring members, a monovalent group containing an aromatic carbon ring structure having 5 or more ring members, and a monovalent group containing an aromatic heterocyclic structure having 5 or more ring members.

[0116] Examples of the alicyclic structure having 5 or more ring members include monocyclic saturated alicyclic structures such as a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure; monocyclic unsaturated alicyclic structures such as a cyclopentene structure, a cyclohexene structure, a cycloheptene structure, a cyclooctene structure, and a cyclodecene structure; polycyclic saturated alicyclic structures such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure; and polycyclic unsaturated alicyclic structures such as a norbornene structure and a tricyclodecene structure.

[0117] Examples of the aliphatic heterocyclic structure having 5 or more ring members include lactone structures such as a hexanolactone structure and a norbornanelactone structure; sultone structures such as a hexanosultone structure and a norbornanesultone structure; oxygen-containing heterocyclic structures such as an oxacycloheptane structure and an oxanorbornane structure; nitrogen-containing heterocyclic structures such as an azacyclohexane structure and a diazabicyclooctane structure; and sulfur-containing heterocyclic structures such as a thiacyclohexane structure and a thianorbornane structure.

[0118] Examples of aromatic carbon ring structures having 5 or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, and an anthracene structure.

[0119] Examples of aromatic heterocyclic structures having 5 or more ring members include oxygen atom-containing heterocyclic structures such as a furan structure, a pyran structure, a benzofuran structure, and a benzopyran structure, and nitrogen atom-containing heterocyclic structures such as a pyridine structure, a pyrimidine structure, and an indole structure.

[0120] R p1The lower limit of the number of ring members of the ring structure is preferably 6, more preferably 8, still more preferably 9, and particularly preferably 10. The upper limit of the number of ring members is preferably 15, more preferably 14, still more preferably 13, and particularly preferably 12. By setting the number of ring members within the above range, the diffusion length of the acid can be further suitably shortened, and as a result, the sensitivity to exposure light and LWR performance of a resist pattern formed from the radiation-sensitive resin composition can be further improved, and the process window can be further expanded.

[0121] R p1 A part or all of the hydrogen atoms in the ring structure may be substituted with a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, and acyloxy group. Among these, a hydroxy group is preferred.

[0122] R p1 As the ring member, a monovalent group containing an alicyclic structure having 5 or more ring members, a monovalent group containing an aliphatic heterocyclic structure having 5 or more ring members, or a monovalent group containing an aromatic ring structure having 5 or more ring members is preferable, and a monovalent group containing a polycyclic saturated alicyclic structure, a monovalent group containing an oxygen atom-containing heterocyclic structure, or a monovalent group containing a sulfur atom-containing heterocyclic structure is more preferable.

[0123] R p2 Examples of the divalent linking group represented by the formula (1) include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, a divalent hydrocarbon group, etc. Among these, a carbonyloxy group, a sulfonyl group, an alkanediyl group, or a divalent alicyclic saturated hydrocarbon group is preferred, and a carbonyloxy group is more preferred.

[0124] R p3 and R p4 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include an alkyl group having 1 to 20 carbon atoms. p3 and R p4Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a fluorinated alkyl group having 1 to 20 carbon atoms. p3 and R p4 is preferably a hydrogen atom, a fluorine atom or a fluorinated alkyl group, more preferably a hydrogen atom, a fluorine atom or a perfluoroalkyl group, and further preferably a hydrogen atom, a fluorine atom or a trifluoromethyl group.

[0125] R p5 and R p6 Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a fluorinated alkyl group having 1 to 20 carbon atoms. p5 and R p6 As the alkyl group, a fluorine atom or a fluorinated alkyl group is preferable, a fluorine atom or a perfluoroalkyl group is more preferable, a fluorine atom or a trifluoromethyl group is further preferable, and a fluorine atom is particularly preferable.

[0126] n p1 As the number, 0 to 5 is preferable, 0 to 2 is more preferable, and 0 or 1 is even more preferable.

[0127] n p2 As the number, 0 to 5 is preferable, 0 to 2 is more preferable, and 0 or 1 is even more preferable.

[0128] n p3 The lower limit of n is preferably 1, and more preferably 2. p3 By making n greater than 1, the strength of the acid can be increased. p3 The upper limit of is preferably 4, more preferably 3, and even more preferably 2.

[0129] n p1 +n p2 +n p3 The lower limit of n is preferably 2, and more preferably 4. p1 +n p2 +n p3 The upper limit of is preferably 20, more preferably 10.

[0130] Examples of the anion (X-1) include anions represented by the following formulas (5-1) to (5-16) (hereinafter also referred to as "anions (X-1-1) to (X-1-16)").

[0131] [ka]

[0132] As the compound (B), a compound in which the above onium cation and the above sulfonate anion are appropriately combined can be used.

[0133] The lower limit of the content of the compound [B] in the radiation-sensitive resin composition is preferably 0.1 parts by mass, more preferably 1 part by mass, and even more preferably 5 parts by mass, relative to 100 parts by mass of the polymer [A]. The upper limit of the content is preferably 80 parts by mass, more preferably 70 parts by mass, and even more preferably 60 parts by mass. By setting the content of the compound [B] within the above range, the sensitivity to exposure light, CDU performance, and LWR performance of the resist pattern formed by the radiation-sensitive resin composition can be further improved.

[0134] <[C] Acid diffusion control agent> The acid diffusion controller [C] has the effect of controlling the diffusion phenomenon in the resist film of the acid generated from the compound [B] etc. by exposure, and controlling undesirable chemical reactions in the non-exposed region. By containing the acid diffusion controller [C] in the radiation-sensitive resin composition, the sensitivity to the exposure light, the CDU performance and the LWR performance of the radiation-sensitive resin composition can be further improved. The radiation-sensitive resin composition can contain one or more types of acid diffusion controller [C].

[0135] Examples of the acid diffusion controller (C) include nitrogen atom-containing compounds and photodecomposable bases that are exposed to light and generate a weak acid.

[0136] Examples of the nitrogen atom-containing compound 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.

[0137] Examples of the photodegradable base include compounds containing an onium cation that decomposes upon exposure and an anion of a weak acid. In the photodegradable base, a weak acid is generated from a proton generated by decomposition of the onium cation and the anion of the weak acid in the exposed area, and therefore the acid diffusion controllability is reduced.

[0138] Examples of the onium cation that decomposes upon exposure include triphenylsulfonium cation, phenyldibenzothiophenium cation, diphenyl(4-(cyclohexylsulfonyl)phenyl)sulfonium cation, and tris(4-fluorophenyl)sulfonium cation.

[0139] Examples of the anion of the weak acid include anions represented by the following formulas.

[0140] [ka]

[0141] As the photodecomposable base, a compound in which the above-mentioned onium cation that decomposes upon exposure and the above-mentioned anion of a weak acid are appropriately combined can be used.

[0142] When the radiation-sensitive resin composition contains an acid diffusion controller [C], the lower limit of the content of the acid diffusion controller [C] is preferably 0.5 parts by mass, more preferably 1 part by mass, and even more preferably 3 parts by mass, relative to 100 parts by mass of the polymer [A]. The upper limit of the content is preferably 40 parts by mass, more preferably 30 parts by mass, and even more preferably 25 parts by mass. By setting the content of the acid diffusion controller [C] within the above range, the sensitivity to exposure light, CDU performance, and LWR performance of the resist pattern formed from the radiation-sensitive resin composition can be further improved.

[0143] <[D] Organic solvent> The radiation-sensitive resin composition usually 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 [A] and the compound [B], as well as the acid diffusion controller [C] and other optional components contained as necessary.

[0144] Examples of the organic solvent [D] include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, hydrocarbon-based solvents, etc. The radiation-sensitive resin composition may contain one or more organic solvents [D].

[0145] Examples of the alcohol solvent include aliphatic monoalcohol solvents having 1 to 18 carbon atoms, such as 4-methyl-2-pentanol and n-hexanol; alicyclic monoalcohol solvents having 3 to 18 carbon atoms, such as cyclohexanol; polyhydric alcohol solvents having 2 to 18 carbon atoms, such as 1,2-propylene glycol; and polyhydric alcohol partial ether solvents having 3 to 19 carbon atoms, such as propylene glycol-1-monomethyl ether.

[0146] Examples of ether 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.

[0147] Examples of the ketone solvent include chain 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; 2,4-pentanedione, acetonylacetone, and acetophenone.

[0148] Examples of the amide solvents include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone, and chain amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0149] Examples of ester-based solvents include monocarboxylic acid ester-based solvents such as n-butyl acetate and ethyl lactate, lactone-based solvents such as γ-butyrolactone and valerolactone, polyhydric alcohol carboxylate-based solvents such as propylene glycol acetate, polyhydric alcohol partial ether carboxylate-based solvents such as propylene glycol monomethyl ether acetate, polyvalent carboxylic acid diester-based solvents such as diethyl oxalate, and carbonate-based solvents such as dimethyl carbonate and diethyl carbonate.

[0150] Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents having 5 to 12 carbon atoms, such as n-pentane and n-hexane, and aromatic hydrocarbon solvents having 6 to 16 carbon atoms, such as toluene and xylene.

[0151] [D] The organic solvent is preferably an alcohol solvent and / or an ester solvent, more preferably a polyhydric alcohol partial ether solvent having 3 to 19 carbon atoms and / or a polyhydric alcohol partial ether carboxylate solvent, and further preferably propylene glycol 1-monomethyl ether and / or propylene glycol monomethyl ether acetate.

[0152] When the radiation-sensitive resin composition contains the organic solvent [D], the lower limit of the content of the organic solvent [D] is preferably 50 mass%, more preferably 60 mass%, further preferably 70 mass%, and particularly preferably 80 mass%, based on the total components contained in the radiation-sensitive resin composition. The upper limit of the content is preferably 99.9 mass%, preferably 99.5 mass%, and further preferably 99.0 mass%.

[0153] <[E] Polymer> The [E] polymer is a polymer having a higher mass content of fluorine atoms than the [A] polymer. Usually, a polymer having a higher hydrophobicity than the base polymer tends to be unevenly distributed on the surface layer of the resist film. The [E] polymer has a higher mass content of fluorine atoms than the [A] polymer, and therefore tends to be unevenly distributed on the surface layer of the resist film due to the characteristics caused by this hydrophobicity. As a result, when the radiation-sensitive resin composition contains the [E] polymer, it is possible to suppress the dissolution of the acid generator, the acid diffusion controller, and the like into the immersion medium during immersion exposure. In addition, when the radiation-sensitive resin composition contains the [E] polymer, it is possible to control the advancing contact angle between the resist film and the immersion medium to a desired range due to the characteristics caused by the hydrophobicity of the [E] polymer, and it is possible to suppress the occurrence of bubble defects. Furthermore, according to the radiation-sensitive resin composition, the receding contact angle between the resist film and the immersion medium becomes large, and high-speed scan exposure is possible without leaving water droplets. By further containing the [E] polymer in this way, the radiation-sensitive resin composition can form a resist film suitable for immersion exposure. Furthermore, since the radiation-sensitive resin composition contains the polymer [E], it is possible to form a resist pattern in which the occurrence of defects is suppressed.

[0154] The lower limit of the mass content of fluorine atoms in the polymer [E] is preferably 1 mass%, more preferably 2 mass%, and even more preferably 3 mass%. The upper limit of the mass content is preferably 60 mass%, more preferably 50 mass%, and even more preferably 40 mass%. By setting the mass content of fluorine atoms in the above range, it is possible to more appropriately adjust the uneven distribution of the polymer [E] in the resist film. The mass content of fluorine atoms in the polymer is 13 The structure of the polymer is determined by C-NMR spectrum measurement, and the molecular weight can be calculated from the structure.

[0155] The form in which fluorine atoms are contained in the polymer [E] is not particularly limited, and the fluorine atoms may be bonded to either the main chain or the side chain of the polymer [E]. As the form in which fluorine atoms are contained in the polymer [E], it is preferable that the polymer [E] has a structural unit containing a fluorine atom (hereinafter also referred to as "structural unit (I')"). The polymer [E] may further have a structural unit other than the structural unit (I'). The polymer [E] may have one or more types of each structural unit. The radiation-sensitive resin composition may contain one or more types of the polymer [E].

[0156] Each structural unit contained in the polymer [E] will be described below.

[0157] [Structural unit (I')] The structural unit (I') is a structural unit containing a fluorine atom. Examples of the structural unit (I') include a structural unit represented by the following formula (f) (hereinafter, also referred to as "structural unit (I'-1)").

[0158] [ka]

[0159] In the above formula (f), R f1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 2 is a single bond, oxygen atom, sulfur atom, -COO-, -SO 2 NH-, -CONH- or -OCONH-. f2 is a monovalent organic group having 1 to 10 carbon atoms and containing a fluorine atom.

[0160] R f1 From the viewpoint of copolymerizability of the monomer that gives the structural unit (I'-1), a hydrogen atom or a methyl group is preferable, and a methyl group is more preferable.

[0161] L 2 As the group, -COO- is preferable.

[0162] R f2Examples of the monovalent organic group having 1 to 10 carbon atoms and a fluorine atom represented by the formula (1) include R 1 , R 2 or R 3 Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the following formula include the same groups as those exemplified above.

[0163] R f2 As the alkyl group, a fluorinated chain hydrocarbon group or a group in which some or all of the hydrogen atoms of this fluorinated chain hydrocarbon group have been substituted with hydroxy groups is preferred.

[0164] The structural unit (I'-1) is preferably a structural unit represented by the following formula:

[0165] [ka]

[0166] In the above formula, R f1 has the same meaning as formula (f) above.

[0167] When the polymer [E] has the structural unit (I'), the lower limit of the content of the structural unit (I') is preferably 20 mol%, more preferably 30 mol%, and even more preferably 40 mol% based on the total structural units constituting the polymer [E]. The upper limit of the content is preferably 90 mol%, more preferably 80 mol%, and even more preferably 70 mol%. By setting the content of the structural unit (F) within the above range, the mass content of fluorine atoms in the polymer [E] can be adjusted more appropriately.

[0168] [Other structural units] Examples of the other structural units include a structural unit having an acid-dissociable group (hereinafter, also referred to as "structural unit (II')"). Examples of the structural unit (II') include the same structural units as those exemplified as the structural unit (I) of the polymer [A] described above.

[0169] When the polymer [E] has the structural unit (II'), the lower limit of the content of the structural unit (II') is preferably 10 mol%, more preferably 20 mol%, and even more preferably 30 mol% based on the total structural units constituting the polymer [E].The upper limit of the content is preferably 80 mol%, more preferably 70 mol%, and even more preferably 60 mol%.

[0170] The lower limit of the Mw of the polymer [E] as determined by GPC is preferably 1,000, more preferably 2,000, further preferably 3,000, and particularly preferably 4,000. The upper limit of the Mw is preferably 50,000, more preferably 20,000, further preferably 10,000, and particularly preferably 8,000.

[0171] The upper limit of the ratio of Mw to Mn (Mw / Mn) of the polymer [E] measured by GPC is preferably 5.00, more preferably 3.00, further preferably 2.50, and particularly preferably 2.00. The lower limit of the ratio is usually 1.00, and preferably 1.20.

[0172] The polymer [E] can be synthesized, like the polymer [A], by polymerizing monomers that provide each structural unit by a known method.

[0173] When the radiation-sensitive resin composition contains the polymer [E], the lower limit of the content of the polymer [E] is preferably 0.5 parts by mass, more preferably 1 part by mass, and even more preferably 5 parts by mass, relative to 100 parts by mass of the polymer [A]. The upper limit of the content is preferably 20 parts by mass, more preferably 15 parts by mass, and even more preferably 10 parts by mass.

[0174] <Other optional ingredients> Examples of the other optional components include acid generators other than the compound [B] (hereinafter also referred to as "other acid generators"), surfactants, etc. The radiation-sensitive resin composition may contain one or more other optional components.

[0175] Other examples of the acid generator include onium salt compounds, N-sulfonyloxyimide compounds, sulfonimide compounds, halogen-containing compounds, and diazoketone compounds.

[0176] Examples of the onium salt compound include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, and pyridinium salts.

[0177] Specific examples of other acid generators include the compounds described in paragraphs

[0080] to

[0113] of JP-A-2009-134088.

[0178] When the radiation-sensitive resin composition contains another acid generator, the lower limit of the content of the other acid generator in the radiation-sensitive resin composition is preferably 0.1 parts by mass, more preferably 1 part by mass, relative to 100 parts by mass of the polymer [A], and the upper limit of the content is preferably 30 parts by mass, more preferably 20 parts by mass.

[0179] <Method for preparing radiation-sensitive resin composition> The radiation-sensitive resin composition can be prepared, for example, by mixing [A] a polymer, [B] a compound, and, if necessary, [C] an acid diffusion controller, [D] an organic solvent, [E] a polymer and other optional components, in a predetermined ratio, and filtering the resulting mixture preferably through a membrane filter having a pore size of 0.2 μm or less.

[0180] <Method of forming resist pattern> The method for forming a resist pattern includes a step of directly or indirectly applying the radiation-sensitive resin composition to a substrate (hereinafter also referred to as a "coating step"), a step of exposing the resist film formed by the coating step (hereinafter also referred to as an "exposure step"), and a step of developing the exposed resist film (hereinafter also referred to as a "development step"). In the coating step of the method for forming a resist pattern, the above-mentioned radiation-sensitive resin composition is used as the radiation-sensitive resin composition.

[0181] According to the method for forming a resist pattern, by using the above-mentioned radiation-sensitive resin composition as the radiation-sensitive resin composition in the coating step, a resist pattern that has good sensitivity to exposure light and excellent CDU performance and LWR performance can be formed.

[0182] Each step of the resist pattern forming method will be described below.

[0183] [Coating process] In this step, the radiation-sensitive resin composition is applied directly or indirectly to a substrate, thereby forming a resist film directly or indirectly on the substrate.

[0184] In this step, the above-mentioned radiation-sensitive resin composition is used as the radiation-sensitive resin composition.

[0185] Examples of the substrate include conventionally known substrates such as silicon wafers, silicon dioxide wafers, and aluminum-coated wafers. Examples of the case where the radiation-sensitive resin composition is indirectly applied to a substrate include the case where the radiation-sensitive resin composition is applied onto an anti-reflection film formed on a substrate. Examples of such anti-reflection films include organic or inorganic anti-reflection films disclosed in, for example, JP-B-6-12452 and JP-A-59-93448.

[0186] Examples of the coating method include rotary coating (spin coating), casting coating, roll coating, and the like. After coating, soft baking (hereinafter also referred to as "SB" or "pre-bake (PB)") may be performed as necessary to volatilize the solvent in the coating film. The lower limit of the SB temperature is preferably 60°C, more preferably 80°C. The upper limit of the temperature is preferably 150°C, more preferably 140°C. The lower limit of the SB time is preferably 5 seconds, more preferably 10 seconds. The lower limit of the time is preferably 600 seconds, more preferably 300 seconds. The lower limit of the average thickness of the resist film to be formed is preferably 10 nm, more preferably 20 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm.

[0187] [Exposure process] In this step, the resist film formed in the coating step is exposed to light. This exposure is performed by irradiating the resist film through a photomask (or through an immersion medium such as water, in some cases). Examples of the exposure light include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays, and gamma rays; charged particle beams such as electron beams and alpha rays, depending on the line width of the desired pattern. 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, and ArF excimer laser light, EUV, or electron beams are even more preferred.

[0188] After the exposure, it is preferable to perform post-exposure baking (hereinafter, also referred to as "PEB") to promote dissociation of the acid-dissociable group of the polymer [A] etc. by the acid generated from the compound [B] etc. by exposure in the exposed part of the resist film. This PEB can increase the difference in solubility in the developer between the exposed part and the non-exposed part. 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.

[0189] [Development process] In this step, the exposed resist film is developed. This allows a desired resist pattern to be formed. After development, the resist film is generally washed with a rinse liquid such as water or alcohol, and then dried. The developing method in the developing step may be either alkaline development or organic solvent development.

[0190] In the case of alkaline development, examples of the developer used for development include an alkaline aqueous solution in which at least one of alkaline compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia water, 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 is dissolved. Among these, a TMAH aqueous solution is preferred, and a 2.38 mass % TMAH aqueous solution is more preferred.

[0191] In the case of organic solvent development, examples of the developer include organic solvents such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, and alcohol solvents, and solutions containing the above organic solvents. Examples of the organic solvent include one or more of the solvents exemplified as the organic solvent [D] of the radiation-sensitive resin composition. Among these, ester solvents or ketone solvents are preferred. As the ester solvent, acetate solvents are preferred, and n-butyl acetate is more preferred. As the ketone solvent, chain ketones are preferred, and 2-heptanone is more preferred. The lower limit of the content of the organic solvent 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 the organic solvent in the developer include water and silicone oil.

[0192] Development methods include, for example, a method in which the substrate is immersed in a tank filled with developer for a certain period of time (dip method), a method in which the developer is piled up on the substrate surface by surface tension and left to stand for a certain period of time (paddle method), a method in which the developer is sprayed onto the substrate surface (spray method), and a method in which the developer is continuously dispensed by scanning a developer dispensing nozzle at a constant speed over a substrate rotating at a constant speed (dynamic dispense method).

[0193] Examples of patterns formed by the resist pattern forming method include line and space patterns and hole patterns.

[0194] <Compound> This compound is described above as the compound [B] of the radiation-sensitive resin composition, and can be suitably used as a radiation-sensitive acid generator in the radiation-sensitive resin composition. EXAMPLES

[0195] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The methods for measuring the various physical properties are shown below.

[0196] [Weight average molecular weight (Mw), number average molecular weight (Mn) and dispersity (Mw / Mn)] The Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) using Tosoh Corporation's GPC columns (two "G2000HXL", one "G3000HXL" and one "G4000HXL") under the following conditions. Elution solvent: Tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Column temperature: 40℃ Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0197] [Structural unit content] The content ratio of each structural unit in the polymer was measured using a nuclear magnetic resonance apparatus (JNM-Delta400 manufactured by JEOL Ltd.). 13 It was measured by C-NMR analysis.

[0198] <Polymer synthesis> Monomers represented by the following formulae (M-1) to (M-26) (hereinafter also referred to as "monomers (M-1) to (M-26)") were used in the synthesis of polymer [A]. Monomer (M-1), monomer (M-2), and monomers represented by the following formulae (M-27) to (M-28) (hereinafter also referred to as "monomers (M-27) to (M-28)") were used in the synthesis of polymer [E]. In the following synthesis examples, unless otherwise specified, parts by mass refer to a value in which the total mass of the monomers used is taken as 100 parts by mass, and mol % refers to a value in which the total number of moles of the monomers used is taken as 100 mol %.

[0199] [ka]

[0200] <Synthesis of polymer [A]> [Synthesis Example 1] Synthesis of polymer (A-1) Monomer (M-1) and monomer (M-10) were dissolved in 2-butanone (200 parts by mass) so that the molar ratio was 45 / 55. Next, azobisisobutyronitrile (5 mol%) was added as an initiator to prepare a monomer solution. 2-butanone (100 parts by mass) was placed in a reaction vessel, and nitrogen purging was performed for 30 minutes. The reaction vessel was heated to 80°C, and the monomer solution was dropped over 3 hours while stirring. The start of the dropwise addition was set as the start time of the polymerization reaction, and the polymerization reaction was performed for 6 hours. After the polymerization reaction was completed, the polymerization solution was cooled with water to 30°C or less. The cooled polymerization solution was poured into methanol (2000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol (400 parts by mass), filtered, and dried at 60°C for 15 hours to obtain a white powdery polymer (A-1) (yield 67%). The Mw of the obtained polymer (A-1) was 6,803, and the Mw / Mn was 1.43. 13 As a result of C-NMR analysis, the contents of the structural units derived from the monomer (M-1) and the monomer (M-10) in the polymer (A-1) were 42 mol % and 58 mol %, respectively.

[0201] [Synthesis Examples 2 to 10] Synthesis of Polymers (A-2) to (A-10) Polymers (A-2) to (A-10) were synthesized in the same manner as in Synthesis Example 1, except that the types and amounts of monomers used were as shown in Table 1 below.

[0202] [Synthesis Example 11] Synthesis of polymer (A-11) Monomer (M-1), monomer (M-17) and monomer (M-18) were dissolved in propylene glycol 1-monomethyl ether (200 parts by mass) so that the molar ratio was 30 / 10 / 60. Next, azobisisobutyronitrile (4 mol%) was added as an initiator to prepare a monomer solution. Meanwhile, propylene glycol 1-monomethyl ether (100 parts by mass) was added to an empty reaction vessel and heated to 85°C while stirring. Next, the monomer solution prepared above was dropped over 3 hours, and then heated at 85°C for another 3 hours, and the polymerization reaction was carried out for a total of 6 hours. After the polymerization reaction was completed, the polymerization solution was cooled to room temperature. The cooled polymerization solution was poured into hexane (500 parts by mass relative to the polymerization solution), and the precipitated white powder was filtered off. The filtered white powder was washed twice with 100 parts by mass of hexane relative to the polymerization solution, filtered off, and dissolved in propylene glycol 1-monomethyl ether (300 parts by mass). Next, methanol (500 parts by mass), triethylamine (50 parts by mass) and ultrapure water (10 parts by mass) were added, and hydrolysis reaction was carried out at 70°C for 6 hours while stirring. After completion of the reaction, the remaining solvent was distilled off, and the obtained solid was dissolved in acetone (100 parts by mass). The resin was coagulated by dropping into 500 parts by mass of water, and the obtained solid was filtered. The mixture was dried at 50°C for 12 hours to obtain a white powdery polymer (A-11) (yield 62%). The Mw of the obtained polymer (A-11) was 6,981, and the Mw / Mn was 1.61. In addition, 13 As a result of C-NMR analysis, the contents of the structural units derived from the monomer (M-1), the monomer (M-17) and the monomer (M-18) in the polymer (A-11) were 27 mol %, 9 mol % and 64 mol %, respectively.

[0203] [Synthesis Examples 12 to 19] Synthesis of Polymers (A-12) to (A-19) Polymers (A-12) to (A-19) were synthesized in the same manner as in Synthesis Example 11, except that the types and amounts of monomers used were as shown in Table 1 below.

[0204] The proportion of monomers giving each structural unit of polymer [A] obtained in Synthesis Examples 1 to 19, the content ratio of each structural unit, yield, Mw and Mw / Mn are shown in the following Table 1. In Table 1, "-" indicates that the corresponding monomer was not used.

[0205] [Table 1]

[0206] <[E] Polymer Synthesis> [Synthesis Example 20] Synthesis of polymer (E-1) Monomer (M-1) and monomer (M-28) were dissolved in 2-butanone (200 parts by mass) so that the molar ratio was 50 / 50. Azobisisobutyronitrile (5 mol%) was added thereto as an initiator to prepare a monomer solution. 2-butanone (100 parts by mass) was placed in a reaction vessel, and nitrogen purging was performed for 30 minutes. The reaction vessel was heated to 80°C, and the monomer solution was dropped over 3 hours while stirring. The start of the dropwise addition was set as the start time of the polymerization reaction, and the polymerization reaction was performed for 6 hours. After the polymerization reaction was completed, the polymerization solution was cooled with water to 30°C or less. The solvent was replaced with acetonitrile (400 parts by mass), and then hexane (100 parts by mass) was added and stirred, and the acetonitrile layer was collected. This operation was repeated three times. The solvent was replaced with propylene glycol monomethyl ether acetate to obtain a solution of polymer (E-1) (yield 79%). The Mw of the obtained polymer (E-1) was 4,988, and the Mw / Mn was 1.71. 13 As a result of C-NMR analysis, the content ratios of the structural units derived from the monomer (M-1) and the monomer (M-28) in the polymer (E-1) were 47 mol % and 53 mol %, respectively.

[0207] [Synthesis Example 21] Synthesis of polymer (E-2) A polymer (E-2) was synthesized in the same manner as in Synthesis Example 20, except that the types and amounts of monomers shown in Table 2 below were used.

[0208] The proportion of monomers giving each structural unit of the polymer [E] obtained in Synthesis Examples 20 to 21, the content of each structural unit, yield, Mw and Mw / Mn are shown in Table 2 below.

[0209] [Table 2]

[0210] <Synthesis of [B] compound> [Synthesis Example 22] Synthesis of compound (B-1) Bromoacetyl bromide (59.0 mmol) was dissolved in dichloromethane to prepare a 1M solution. After cooling the solution to 0°C, a mixed solution of 118.0 mmol of tert-butyl alcohol and 118.0 mmol of pyridine was added at a rate such that the temperature did not exceed 10°C, and the reaction was allowed to proceed at room temperature for 1 hour. After quenching with a saturated aqueous ammonium chloride solution, the mixture was extracted with dichloromethane and the organic layer was dried over sodium sulfate. After distilling off the solvent, the mixture was purified by column chromatography to obtain tert-butyl-2-bromoacetate (yield 75%). The synthesis scheme of tert-butyl-2-bromoacetate is shown below.

[0211] [ka]

[0212] In a reaction vessel, 40.0 mmol of the synthesized tert-butyl-2-bromoacetate was dissolved in acetone to prepare a 1M solution, and the solution was then cooled to 0°C. 45.0 mmol of sodium thioacetate was gradually added over 1 hour, and the solution was stirred at room temperature for 1 hour. After the reaction was completed, the mixture was quenched with a saturated aqueous ammonium chloride solution, and then extracted with dichloromethane to separate the organic layer. The organic layer was dried over sodium sulfate, and the solvent was distilled off to obtain tert-butyl-2-(acetylthio)acetate (yield 95%). The synthesis scheme of tert-butyl-2-(acetylthio)acetate is shown below.

[0213] [ka]

[0214] In a reaction vessel, 30 mmol of the synthesized tert-butyl-2-(acetylthio)acetate was dissolved in a methanol / water mixed solvent to obtain a 1M solution, and then cooled to 0°C. After cooling, 33 mL of 1M lithium hydroxide aqueous solution was added little by little over 1 hour, and then stirred at room temperature for 1 hour. After the reaction was completed, toluene was added for extraction, and the organic layer was discarded. The aqueous layer was neutralized with 1M hydrochloric acid to pH 5, and then extracted with ethyl acetate to separate the organic layer. The organic layer was dried over sodium sulfate, the solvent was removed, and column purification was performed to obtain tert-butyl-2-mercaptoacetate (yield 91%). The synthesis scheme of tert-butyl-2-mercaptoacetate is shown below.

[0215] [ka]

[0216] 20 mmol of tert-butyl-2-mercaptoacetate and 20 mmol of the compound represented by the following formula (PB-1) were dissolved in a dimethylformamide solvent in a reaction vessel to make the solution 1M, and then cooled to 0°C. After cooling, 22 mmol of potassium carbonate was added little by little over 1 hour, and the mixture was stirred at room temperature for 1 hour. After the reaction was completed, the mixture was quenched with a saturated aqueous ammonium chloride solution, and then extracted with dichloromethane to separate the organic layer. The organic layer was dried over sodium sulfate, and the solvent was distilled off to obtain a compound represented by the following formula (PB-2) (hereinafter also referred to as "compound (PB-2)") (yield 95%). The synthesis scheme of compound (PB-2) is shown below.

[0217] [ka]

[0218] In a reaction vessel, 15 mmol of the compound (PB-2) synthesized above was dissolved in a mixed solvent of acetonitrile / water = 3 / 1 (volume ratio) to make it 1M, and then 45 mmol of Oxone (registered trademark) (Tokyo Chemical Industry Co., Ltd.) was added little by little over 1 hour, and then the mixture was stirred at room temperature for 8 hours. After the reaction was completed, the mixture was quenched with a saturated aqueous sodium sulfite solution, and then extracted with dichloromethane to separate the organic layer. The organic layer was dried with sodium sulfate, and the solvent was distilled off and column purified to obtain a compound represented by the following formula (B-1) (hereinafter also referred to as "compound (B-1)") (yield 95%). The synthesis scheme of compound (B-1) is shown below.

[0219] [ka]

[0220] [Synthesis Examples 23 to 36] Synthesis of Compounds (B-2) to (B-15) Compounds represented by the following formulas (B-2) to (B-15) (hereinafter also referred to as "compounds (B-2) to (B-15)") were synthesized in the same manner as in Synthesis Example 22, except that the precursors were appropriately changed.

[0221] [ka]

[0222] [ka]

[0223] <Preparation of Radiation-Sensitive Resin Composition> The acid generators other than the compound [B], the acid diffusion controller [C], and the organic solvent [D] used in the preparation of the radiation-sensitive resin composition are shown below. In the following examples and comparative examples, unless otherwise specified, parts by mass refer to a value when the mass of the polymer [A] used is taken as 100 parts by mass, and mol % refers to a value when the number of moles of the compound [B] used is taken as 100 mol %.

[0224] [[B] Acid generator other than compound] (B-16) to (B-18): Compounds represented by the following formulas (B-16) to (B-18)

[0225]

Chemical formula

[0226] [[C] Acid diffusion control agent] (C-1) to (C-6): Compounds represented by the following formulas (C-1) to (C-6)

[0227]

Chemical formula

[0228] [D] Organic solvent] D-1: Propylene glycol 1-methyl ether acetate D-2: Propylene glycol 1-methyl ether

[0229] <Preparation of a radiation-sensitive resin composition for ArF lithography> [Example 1] Preparation of a radiation-sensitive resin composition (J-1) 100 parts by mass of (A-1) as [A] polymer, 15 parts by mass of (B-1) as [B] compound, 8.0 parts by mass of (C-1) as [C] acid diffusion control agent, 2,240 parts by mass of (D-1) and 960 parts by mass of (D-2) as [D] organic solvents, and 7 parts by mass of (E-1) as [E] polymer were mixed and filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive resin composition (J-1).

[0230] [Examples 2 to 21 and Comparative Examples 1 to 2] Preparation of radiation-sensitive resin compositions (J-2) to (J-21) and (CJ-1) to (CJ-2) Radiation-sensitive resin compositions (J-2) to (J-21) and (CJ-1) to (CJ-2) were prepared in the same manner as in Example 1 except that the components of the types and contents shown in Table 3 below were used.

[0231]

Table 3

[0232] <Formation of Resist Pattern Using ArF Exposure-Sensitive Radiation Curable Resin Composition> On a 12-inch silicon wafer, using a spin coater ("CLEAN TRACK ACT12" of Tokyo Electron Limited), a composition for forming an underlying antireflective film ("ARC66" of Brewer Science, Inc.) was applied, and then heated at 205 °C for 60 seconds to form an underlying antireflective film with an average thickness of 105 nm. On this underlying antireflective film, each of the prepared ArF exposure-sensitive radiation curable resin compositions was applied using the above spin coater, and PB was performed at 120 °C for 50 seconds. Then, it was cooled at 23 °C for 30 seconds to form a resist film with an average thickness of 90 nm. Next, for this resist film, using an ArF excimer laser immersion exposure apparatus ("TWINSCAN XT-1900i" of ASML), under optical conditions of NA = 1.35 and Annular (σ = 0.8 / 0.6), exposure was performed through a mask pattern for forming a resist pattern with a 44 nm space and a 102 nm pitch. After exposure, PEB was performed at 90 °C for 60 seconds. Then, using a 2.38 mass% aqueous TMAH solution, paddle development was performed at 23 °C for 10 seconds, and spin drying was performed at 2,000 rpm for 15 seconds to form a resist pattern with a 45 nm space.

[0233] <Evaluation> Regarding the resist pattern formed using the above ArF exposure-sensitive radiation curable resin composition, sensitivity, CDU performance, and LWR performance were evaluated according to the following methods. The results are shown in Table 4 below. For the length measurement of the resist pattern, a scanning electron microscope ("CG-5000" of Hitachi High-Technologies Corporation) was used.

[0234] [Sensitivity] In the formation of the resist pattern using each of the above ArF exposure-sensitive radiation curable resin compositions, the exposure amount for forming a 40 nm line and space pattern was defined as the optimum exposure amount, and this optimum exposure amount was designated as Eop (unit: mJ / cm 2The sensitivity was Eop of 25 mJ / cm 2 The following are considered "good" and 25mJ / cm 2 If it exceeded this, it was rated as "poor".

[0235] [CDU performance] A resist pattern was formed by adjusting the mask size so that a pattern with 45 nm holes and 110 nm pitch was formed by irradiating with the exposure dose of Eop determined in the above sensitivity evaluation. The formed resist pattern was observed from above the pattern using the above scanning electron microscope. The hole diameter was measured at 16 points in a range of 500 nm to calculate the average value, and the average value was measured at a total of 500 points at any location. The 1 sigma value was calculated from the distribution of the measured values, and this was defined as CDU (unit: nm). The smaller the CDU value, the smaller the variation in hole diameter over a long period and the better the result. CDU performance was evaluated as "good" when CDU was 6.0 nm or less, and "poor" when it exceeded 6.0 nm.

[0236] [LWR performance] A resist pattern was formed by adjusting the mask size so that a pattern with 45 nm space and 800 nm pitch was formed by irradiating with the exposure dose of Eop determined in the above sensitivity evaluation. The formed resist pattern was observed from above the pattern using the above scanning electron microscope. The line width was measured at 500 arbitrary points in total, and the 3 sigma value was calculated from the distribution of the measured values, which was taken as the LWR (unit: nm). The smaller the LWR value, the smaller the line wobble and the better the result. The LWR performance was evaluated as "good" when the LWR was 5.8 nm or less, and "poor" when it exceeded 5.8 nm.

[0237] [Table 4]

[0238] As is clear from the results in Table 4, the radiation-sensitive resin compositions for ArF exposure of the Examples all had better sensitivity, CDU performance and LWR performance than the radiation-sensitive resin compositions of the Comparative Examples.

[0239] <Preparation of Radiation-Sensitive Resin Composition for EUV Lithography> [Example 22] Preparation of Radiation-Sensitive Resin Composition (J-22) [A] 100 parts by mass of (A-1) as a polymer, [B] 35 parts by mass of (B-1) as a compound, [C] 10.5 parts by mass of (C-2) as an acid diffusion control agent, [D] 4,280 parts by mass and 1,830 parts by mass of (D-1) and (D-2) as organic solvents, and [E] 7 parts by mass of (E-2) as a polymer were mixed and filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive resin composition (J-22).

[0240] [Examples 23 to 45 and Comparative Examples 3 to 4] Preparation of Radiation-Sensitive Resin Compositions (J-23) to (J-45) and (CJ-3) to (CJ-4) Radiation-sensitive resin compositions (J-23) to (J-45) and (CJ-3) to (CJ-4) were prepared in the same manner as in Example 22, except that the components of the types and contents shown in Table 5 below were used.

[0241]

Table 5

[0242] <Formation of Resist Pattern Using Radiation-Sensitive Resin Composition for EUV Lithography> The composition for forming the lower anti-reflective coating was applied onto a 12-inch silicon wafer using the spin coater, and then heated at 205° C. for 60 seconds to form a lower anti-reflective coating having an average thickness of 105 nm. The radiation-sensitive resin composition for EUV exposure prepared above was applied onto this lower anti-reflective coating using the spin coater, and PB was performed at 130° C. for 60 seconds. Then, the coating was cooled at 23° C. for 30 seconds to form a resist film having an average thickness of 55 nm. Next, this resist film was exposed to light using an EUV exposure device (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. Then, the resist film was alkali-developed using a 2.38% by mass TMAH aqueous solution as an alkaline developer, and after development, it was washed with water and further dried to form a positive resist pattern (32 nm line and space pattern).

[0243] <Evaluation> The resist patterns formed using the above-mentioned radiation-sensitive resin composition for EUV exposure were evaluated for sensitivity, CDU performance, and LWR performance according to the following methods. The results are shown in the following Table 6. The above-mentioned scanning electron microscope was used to measure the length of the resist patterns.

[0244] [sensitivity] In forming a resist pattern using the above-mentioned radiation-sensitive resin composition for EUV exposure, the exposure amount for forming a 32 nm line and space pattern was defined as the optimal exposure amount, and this optimal exposure amount was defined as Eop (unit: mJ / cm 2 The sensitivity was Eop of 35 mJ / cm 2 The following are considered "good": 35mJ / cm 2 If it exceeded this, it was rated as "poor".

[0245] [CDU performance] A resist pattern was formed by adjusting the mask size so that a pattern with 35 nm holes and 90 nm pitch was formed by irradiating with the exposure dose of Eop determined in the above sensitivity evaluation. The formed resist pattern was observed from above the pattern using the above scanning electron microscope. The hole diameter was measured at 16 points in a range of 500 nm to calculate the average value, and this average value was measured at a total of 500 points at random locations. The 1 sigma value was calculated from the distribution of the measured values, and this was taken as CDU (unit: nm). CDU performance was evaluated as "good" when CDU was 2.0 nm or less, and "poor" when it exceeded 2.0 nm.

[0246] [LWR performance] A resist pattern was formed by adjusting the mask size so that a 32 nm line and space pattern was formed by irradiating the Eop exposure dose determined in the above sensitivity evaluation. The formed resist pattern was observed from above the pattern using the above scanning electron microscope. A total of 50 points of line width variation were measured, and a 3 sigma value was calculated from the distribution of the measured values, and this 3 sigma value was taken as the LWR (unit: nm). The LWR performance was evaluated as "good" when the LWR was 2.5 nm or less, and "poor" when it exceeded 2.5 nm.

[0247] [Table 6]

[0248] As is clear from the results in Table 6, the radiation-sensitive resin compositions for EUV exposure of the Examples all had better sensitivity, CDU performance, and LWR performance than the radiation-sensitive resin compositions of the Comparative Examples. [Industrial Applicability]

[0249] According to the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention, a resist pattern having good sensitivity to exposure light and excellent CDU performance and LWR performance can be formed. The compound of the present invention can be suitably used as a component of the composition. Therefore, the radiation-sensitive resin composition, the method for forming a resist pattern, and the compound can be suitably used in the processing of semiconductor devices, which are expected to become increasingly finer in the future.

Claims

1. A polymer having a structural unit containing an acid dissociable group; A compound represented by the following formula (1): A radiation-sensitive resin composition comprising: 【Chemistry 1】 (In formula (1), R １ , R ２ and R ３ are each independently a monovalent organic group having 1 to 20 carbon atoms, a halogen atom, a hydroxyl group, or a nitro group. a is an integer from 0 to 7. When a is 2 or more, multiple R １ are the same or different. b is an integer of 0 to 4. When b is 2 or more, a plurality of R ２ are the same or different. c is an integer of 0 to 4. When c is 2 or more, a plurality of R ３ are the same or different. １ , X ２ and X ３ are each independently a group represented by the following formula (2), and d is an integer of 0 to 7. When d is 2 or more, a plurality of X １ are the same or different. e is an integer of 0 to 4. When e is 2 or more, a plurality of X ２ are the same or different. f is an integer of 0 to 4. When f is 2 or more, a plurality of X ３ are the same or different from each other, provided that d+e+f is 1 or more, a+d is 7 or less, b+e is 4 or less, and c+f is 4 or less. R ４ is an aromatic hydrocarbon group having 6 to 20 carbon atoms and a valence of (b+e+1), R ５ is an aromatic hydrocarbon group having 6 to 20 carbon atoms and a valence of (c+f+1), or R ４ and R ５ and are combined with each other to form a dibenzothiophene structure together with the sulfur atom to which they are bonded. n is 0 or 1. － is a monovalent sulfonate anion. 【Chemistry 2】 In formula (2), L is a hydrocarbon group having 1 to 20 carbon atoms and a valence of (m+1). Y is -COO-, -OCO- or -N(R ７ ) CO-. ７ R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. ６ is a monovalent organic group having 1 to 20 carbon atoms, and the organic group is an acid dissociable group, a lactone ring group, a sultone ring group, a carbonate ring group, an alicyclic hydrocarbon group containing an alcoholic hydroxyl group, a phenolic hydroxyl group-containing group, an amide group, or a halogen atom-containing group. m is an integer of 1 to 5. When m is 2 or more, multiple Y's may be the same or different, and multiple R ６ are the same or different. * indicates a bonding site to a portion of the compound other than the group represented by formula (2).

2. 2. The radiation-sensitive resin composition according to claim 1, wherein n in the formula (1) is 0.

3. The radiation-sensitive resin composition according to claim 1, wherein the acid-dissociable group represented by R 6 in the above formula (2) is a group represented by the following formula (2-1): 【Chemistry 3】 (In formula (2-1), R 8 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R 9 and R 10 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or these groups combined with each other to form an alicyclic structure having 3 to 20 ring members together with the carbon atom to which they are bonded. *** indicates the bonding site with Y in formula (2) above.)

4. The radiation-sensitive resin composition according to any one of claims 1 to 3, wherein the halogen atom-containing group represented by R 6 in the above formula (2) is a group in which some or all of the hydrogen atoms of a monovalent hydrocarbon group having 1 to 20 carbon atoms have been substituted with halogen atoms.

5. A step of directly or indirectly applying the radiation-sensitive resin composition according to any one of claims 1 to 4 onto a substrate; a step of exposing the resist film formed by the coating step; developing the exposed resist film; A method for forming a resist pattern comprising the steps of:

6. A compound represented by the following formula (1): 【Chemistry 4】 (In formula (1), R １ , R ２ and R ３ are each independently a monovalent organic group having 1 to 20 carbon atoms, a halogen atom, a hydroxyl group, or a nitro group. a is an integer from 0 to 7. When a is 2 or more, multiple R １ are the same or different. b is an integer of 0 to 4. When b is 2 or more, a plurality of R ２ are the same or different. c is an integer of 0 to 4. When c is 2 or more, a plurality of R ３ are the same or different. １ , X ２ and X ３ are each independently a group represented by the following formula (2), and d is an integer of 0 to 7. When d is 2 or more, a plurality of X １ are the same or different. e is an integer of 0 to 4. When e is 2 or more, a plurality of X ２ are the same or different. f is an integer of 0 to 4. When f is 2 or more, a plurality of X ３ are the same or different from each other, provided that d+e+f is 1 or more, a+d is 7 or less, b+e is 4 or less, and c+f is 4 or less. R ４ is an aromatic hydrocarbon group having 6 to 20 carbon atoms and a valence of (b+e+1), R ５ is an aromatic hydrocarbon group having 6 to 20 carbon atoms and a valence of (c+f+1), or R ４ and R ５ and are combined with each other to form a dibenzothiophene structure together with the sulfur atom to which they are bonded. n is 0 or 1. － is a monovalent sulfonate anion. 【Chemistry 5】 In formula (2), L is a hydrocarbon group having 1 to 20 carbon atoms and a valence of (m+1). Y is -COO-, -OCO- or -N(R ７ ) CO-. ７ R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. ６ is a monovalent organic group having 1 to 20 carbon atoms, and the organic group is an acid dissociable group, a lactone ring group, a sultone ring group, a carbonate ring group, an alicyclic hydrocarbon group containing an alcoholic hydroxyl group, a phenolic hydroxyl group-containing group, an amide group, or a halogen atom-containing group. m is an integer of 1 to 5. When m is 2 or more, multiple Y's may be the same or different, and multiple R ６ are the same or different. * indicates a bonding site to a portion of the compound other than the group represented by formula (2).

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