WO2019189877A1

WO2019189877A1 - Radiation-sensitive resin composition and method for forming resist pattern

Info

Publication number: WO2019189877A1
Application number: PCT/JP2019/014329
Authority: WO
Inventors: 貴史土井; 下川　努; 誠杉浦
Original assignee: Jsr株式会社
Priority date: 2018-03-29
Filing date: 2019-03-29
Publication date: 2019-10-03

Abstract

The present invention is a radiation-sensitive resin composition containing a first polymer having a first structural unit that includes the first group represented by formula (1), a radiation-sensitive cation, and an anion, the proportion of the first structural unit in the first polymer being 50 mol% or more, the molecular volume of an acid formed from the anion and a proton being 2.00 × 10^–28 m³ or less, and the stabilization energy (ΔE) required in formula (A) using density functional theory being 0 kJ/mol or less. Formula (A): stabilization energy (ΔE) = (sum of total energy of the first group, the radiation-sensitive cation, and the anion when the first group and the anion are interacting with each other) – (sum of total energy of the first group, the radiation-sensitive cation, and the anion when the first group and the anion are not interacting with each other) In formula (1), R¹ is a fluorine atom or a C1-20 monovalent fluorinated hydrocarbon group.

Description

Radiation-sensitive resin composition and resist pattern forming method

The present invention relates to a radiation-sensitive resin composition and a resist pattern forming method.

A chemically amplified radiation-sensitive resin composition suitably used for microfabrication by lithography is applied to an exposed portion by irradiation with electromagnetic radiation such as ultraviolet rays, far ultraviolet rays, and extreme ultraviolet rays (EUV), and charged particle beams such as electron beams. A resist pattern is formed on the substrate by a mechanism that generates an acid and causes a difference in the dissolution rate in the developer between the exposed area and the unexposed area by a chemical reaction using this acid as a catalyst. Since it can form a pattern, it is currently used as a mainstream fine pattern forming material.

However, the chemically amplified radiation-sensitive resin composition as described above changes the line width and shape of the resist pattern depending on the retention time (PED) from exposure to post-exposure heat treatment due to the influence of the generated acid. There was a problem with the stability over time.

The present invention has been made based on the above circumstances, and an object thereof is to provide a radiation-sensitive resin composition and a resist pattern forming method capable of forming a fine pattern while being non-chemically amplified. It is in.

The invention made in order to solve the above-mentioned problems is a first structural unit (hereinafter referred to as “structural unit (I)” including a first group represented by the following formula (1) (hereinafter also referred to as “group (I)”). ) ”), A radiation-sensitive cation (hereinafter also referred to as“ cation (Y) ”), and an anion (hereinafter referred to as“ anion ”). (X) "), the content of the structural unit (I) in the polymer [A] is 50 mol% or more, and an acid formed from the anion (X) and a proton ( Hereinafter, the molecular volume of “acid (P)”) is 2.00 × 10 ⁻²⁸ m ³ or less, and the stabilization energy (ΔE) obtained by the following formula (A) by the density functional method is 0 kJ / It is a radiation sensitive resin composition which is less than mol.
Stabilization energy (ΔE) = (total energy of the group (I), the cation (Y), and the anion (X) when the group (I) and the anion (X) interact with each other. (Total)-(sum of all energies of the group (I), the cation (Y), and the anion (X) when the group (I) does not interact with the anion (X))・ (A)

(In the formula (1), R ¹ is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ² is a hydrogen atom, a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. (It is an organic group. * Represents a site bonded to a part other than the group (I) in the structural unit (I).)

Another invention made to solve the above problems is a step of directly or indirectly applying the radiation-sensitive resin composition to the substrate, a step of exposing the resist film formed by the coating step, And a step of developing the exposed resist film.

Here, “organic group” means a group containing at least one carbon atom.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, a fine pattern can be formed even with a non-chemical amplification type. Therefore, according to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, it can overcome the weaknesses of conventional chemically amplified resists, and is suitably used for manufacturing semiconductor devices where further miniaturization is expected in the future. be able to.

<Radiation sensitive resin composition>
The radiation-sensitive resin composition contains a [A] polymer, a cation (Y), and an anion (X) (a combination of the cation (Y) and the anion (X), “[B] compound” Also called). The said radiation sensitive resin composition may contain a [C] solvent as a suitable component, and may contain the other arbitrary components in the range which does not impair the effect of this invention.

The radiation-sensitive resin composition contains a [A] polymer and a [B] compound, and as described later, the content ratio of the structural unit (I) in the [A] polymer is 50 mol% or more. The molecular volume of the acid (P) formed from the anion (X) and the proton is 2.00 × 10 ⁻²⁸ m ³ or less and the stabilization energy (ΔE) is 0 kJ / mol or less, Although it is a non-chemical amplification type, a fine pattern can be formed. The reason why the radiation-sensitive resin composition has the above-described configuration and thus exhibits the above-mentioned effect is not necessarily clear, but can be inferred as follows, for example. That is, when the stabilization energy (ΔE) is not more than the above value and the molecular volume of the acid (P) is not more than the above value, the interaction between the [A] polymer and the [B] compound causes the group (I ) And anion (X) are considered to occur at a certain ratio or more, and the content ratio of the structural unit (I) containing the group (I) in the [A] polymer is set to the above value or more. Thus, it is considered that the [A] polymer can sufficiently reduce the alkali solubility by the interaction with the [B] compound. This [A] polymer becomes alkali-soluble in the exposed area as the radiation-sensitive cation (Y) decomposes upon exposure. The radiation-sensitive resin composition can form a fine pattern even if it is a non-chemical amplification type by such a novel technique.
The said radiation sensitive resin composition can improve the difference of the alkali solubility of an exposed part and an unexposed part, and is excellent in resolution and the remaining film property of an unexposed part.
Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer has the structural unit (I), and the content ratio of the structural unit (I) is 50 mol% or more. [A] The polymer may have, in addition to the structural unit (I), a second structural unit containing an acid dissociable group (hereinafter also referred to as “structural unit (II)”). Other structural units other than I) and (II) may be included, and each structural unit will be described below.

[Structural unit (I)]
The structural unit (I) is a structural unit containing the group (I). The group (I) is a group represented by the following formula (1).

In the above formula (1), R ¹ is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ² is a hydrogen atom, a fluorine atom or a monovalent organic group having 1 to 20 carbon atoms. * Shows the site | part couple | bonded with parts other than the said group (I) in the said structural unit (I).

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ¹ include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, and nonafluorobutyl. Fluorinated alkyl groups such as groups;
A fluorinated alkenyl group such as a trifluoroethenyl group;
Fluorinated chain hydrocarbon groups such as fluorinated alkynyl groups such as fluoroethynyl groups,
A fluorinated alicyclic saturated hydrocarbon group such as a fluorocyclopentyl group, a perfluorocyclopentyl group, a fluorocyclohexyl group, a perfluorocyclohexyl group;
A fluorinated alicyclic hydrocarbon group such as a fluorinated alicyclic unsaturated hydrocarbon group such as a fluorocyclopentenyl group,
Fluorinated aryl groups such as a fluorophenyl group, a trifluorophenyl group, a perfluorophenyl group;
Examples thereof include fluorinated aromatic hydrocarbon groups such as a fluorinated aralkyl group such as a fluorobenzyl group.

R ¹ is preferably a fluorinated chain hydrocarbon group, more preferably a fluorinated alkyl group, and even more preferably a trifluoromethyl group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ² include a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a divalent heteroatom containing carbon-carbon of the hydrocarbon group. A monovalent group (g) containing a group, a monovalent group (h) in which part or all of the hydrogen atoms of the hydrocarbon group and the group (g) are substituted with a monovalent heteroatom-containing group, the carbonization Examples thereof include a hydrogen group, a group (g) or a monovalent group (i) in which a group (g) and a divalent heteroatom-containing group are combined. When the hetero atom-containing group contains a carbon atom, the number of carbon atoms is also included in the organic group having 1 to 20 carbon atoms.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and 6 carbon atoms. And 20 monovalent aromatic hydrocarbon groups.

The “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure but includes only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. 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 a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, it is not necessary to be composed only of the alicyclic structure, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure.

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

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic alicyclic saturated hydrocarbon groups such as a cyclopentyl group and a cyclohexyl group;
Monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopentenyl group and cyclohexenyl group;
Polycyclic alicyclic saturated hydrocarbon groups such as norbornyl group, adamantyl group and tricyclodecyl group;
Examples thereof include polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group and a tricyclodecenyl group.

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;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group and anthrylmethyl group.

Examples of the hetero atom contained in the monovalent or divalent heteroatom-containing group include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, and a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the divalent heteroatom-containing group include —O—, —CO—, —S—, —CS—, —NR′—, —SO—, —SO ₂ —, and combinations of two or more thereof. And the like. R ′ is a hydrogen atom or a monovalent carbon hydrogen group.

Examples of the monovalent heteroatom-containing group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, amino group and sulfanyl group.

R ² is preferably a fluorinated hydrocarbon group, more preferably a fluorinated chain hydrocarbon group, still more preferably a fluorinated alkyl group, and particularly preferably a trifluoromethyl group.

Examples of the group (I) include groups represented by the following formulas (1-1) to (1-9) (hereinafter also referred to as “groups (I-1) to (I-9)”). .

In the above formulas (1-1) to (1-9), * has the same meaning as the above formula (1).

Of these, the group (I-1) is preferred.

In the structural unit (I), the group (I) is preferably bonded to an aromatic ring.

Examples of the structural unit (I) include structural units represented by the following formulas (3-1) to (3-9) (hereinafter also referred to as “structural units (I-1) to (I-9)”), etc. Is mentioned.

In the above formulas (3-1) to (3-3), each R ³ is independently a hydrogen atom or a methyl group.
In the above formulas (3-4) to (3-8), each R ⁴ is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^p , R ^q , R ^r , R ^s , R ^t and R ^u are each independently a hydrogen atom, a fluorine atom or a monovalent organic group having 1 to 20 carbon atoms.
In the above formula (3-9), R ⁵ represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The structural unit (I-1) is preferable as the structural unit (I).

As a content rate of structural unit (I), it is 50 mol% or more with respect to all the structural units which comprise a [A] polymer, 60 mol% or more is preferable, 70 mol% or more is more preferable, 72 mol % Or more is particularly preferable. Moreover, as said content rate, it is 100 mol% or less, for example, 90 mol% or less is preferable and 85 mol% or less is more preferable. By setting the content ratio of the structural unit (I) in the above range, the difference in alkali solubility between the exposed part and the unexposed part can be further improved, and the resolution and the remaining film property of the unexposed part can be further improved. Can be improved.

The structural unit (I) may have one group (I) or two or more groups (I).

[A] When the polymer includes a structural unit having two or more groups (I) as the structural unit (I), the content ratio of the group (I) represented by the following formula (3) is 50 mol%. The above is preferable, 60 mol% is more preferable, 70 mol% is further more preferable, and 75 mol% is especially preferable. Moreover, as said content rate, it is 100 mol% or less, for example, 90 mol% or less is preferable and 85 mol% or less is more preferable.
([A] number of groups (I) in polymer) × 100 / ([A] number of all structural units in polymer) (3)

[Structural unit (II)]
The structural unit (II) is a structural unit containing an acid dissociable group. The “acid-dissociable group” refers to a group that replaces a hydrogen atom such as a carboxy group, a sulfo group, or a phenolic hydroxyl group and that dissociates by the action of an acid. [A] When the polymer has the structural unit (II), the acid dissociable group is dissociated by the action of an acid or the like generated by exposure from the [B] compound described later, and as a result, the developer of [A] polymer It is possible to further improve the solubility change with respect to.

Examples of the structural unit (II) include a structural unit represented by the following formula (4-1A) (hereinafter also referred to as “structural unit (II-1-1)”), and a structural unit represented by the following formula (4-1B). Structural unit (hereinafter also referred to as “structural unit (II-1-2)”), a structural unit represented by the following formula (4-2A) (hereinafter also referred to as “structural unit (II-2-1)”) ), A structural unit represented by the following formula (4-2B) (hereinafter also referred to as “structural unit (II-2-2)”), and the like.

In the above formulas (4-1A), (4-1B), (4-2A) and (4-2B), R ^T each independently represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. is there.
In the above formulas (4-1A) and (4-1B), R ^X each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^Y and R ^Z are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a ring member having 3 to 3 ring atoms composed of these groups together with the carbon atom to which they are bonded. This represents a part of the 20 alicyclic structures.
In the above formulas (4-2A) and (4-2B), R ^U , R ^V and R ^W are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or these groups A part of a ring structure having 4 to 20 ring members constituted by a carbon atom or C—O, in which two or more of them are combined with each other.

^RT is preferably a hydrogen atom or a methyl group from the viewpoint of the copolymerizability of the monomer that gives the structural unit (II).

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^X to R ^Z and R ^U to R ^W are the same groups as the hydrocarbon groups exemplified as R ^{1 in the} above formula (1). Etc.

Examples of the ring structure having 4 to 20 ring members constituted by two or more of R ^Y and R ^Z and R ^U to R ^W include monocyclic rings such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, and a cyclohexane structure. Saturated alicyclic structure;
Polycyclic saturated alicyclic structures such as norbornane structure, adamantane structure, tricyclodecane structure and tetracyclododecane structure;
Monocyclic unsaturated alicyclic structure such as cyclopropene structure, cyclobutene structure, cyclopentene structure, cyclohexene structure;
Polycyclic unsaturated alicyclic structures such as norbornene structure, tricyclodecene structure, tetracyclododecene structure,
Examples thereof include oxacycloalkane structures such as oxacyclobutane structure, oxacyclopentane structure, and oxacyclohexane structure; oxacycloalkene structures such as oxacyclobutene structure, oxacyclopentene structure, and oxacyclohexene structure.

Since the resist pattern can be formed if the polymer [A] has the structural unit (I), the polymer [A] has the structural unit (II) even if it has the structural unit (II). It does not have to be. [A] When the polymer does not have the structural unit (II), it is not necessary to perform post-exposure baking (PEB) after exposure, and the process of forming a resist pattern can be simplified. [A] When the polymer has the structural unit (II), the content ratio of the structural unit (II) is preferably 20 mol% or less with respect to all the structural units constituting the [A] polymer, preferably 10 mol. % Or less is more preferable.

[Other structural units]
As other structural units, for example, structural units derived from substituted or unsubstituted styrene, structural units derived from (meth) acrylic acid or (meth) acrylic acid esters, structural units derived from substituted or unsubstituted ethylene, Examples include a structural unit containing a polar group, a lactone structure, a cyclic carbonate structure, a sultone structure, or a structural unit containing a combination thereof (excluding those corresponding to the structural unit (I) and the structural unit (II)). Examples of the polar group include an alcoholic hydroxy group, a carboxy group, a cyano group, a nitro group, and a sulfonamide group. [A] When the polymer has other structural units, the solubility in the developer can be adjusted, and as a result, the resolution and the remaining film property of the unexposed area can be further improved.

Examples of the substituted styrene include α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, pt-butyl styrene, 2,4,6-trimethyl styrene, p-methoxy styrene, pt -Butoxystyrene, o-vinylstyrene, m-vinylstyrene, p-vinylstyrene, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, m-chloromethylstyrene, p-chloromethylstyrene, p-fluorostyrene , P-chlorostyrene, p-bromostyrene, p-iodostyrene, p-nitrostyrene, p-cyanostyrene, p-trimethoxysilylstyrene, and the like.

Examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. ;
Cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, 1-methylcyclopentyl (meth) acrylate, 2-ethyladamantyl (meth) acrylate, 2- (adamantan-1-yl) propyl (meth) acrylate, etc. (Meth) acrylic acid cycloalkyl ester of
(Meth) acrylic acid aryl esters such as phenyl (meth) acrylate and naphthyl (meth) acrylate;
(Meth) acrylic acid-substituted alkyl esters such as 2-hydroxyethyl (meth) acrylate, 3-hydroxyadamantyl (meth) acrylate, 3-glycidylpropyl (meth) acrylate, 3-trimethylsilylpropyl (meth) acrylate, etc. Is mentioned.

Examples of the substituted ethylene include alkenes such as propene, butene, and pentene;
Vinylcycloalkanes such as vinylcyclopentane and vinylcyclohexane;
Cycloalkenes such as cyclopentene and cyclohexene;
Examples include 4-hydroxy-1-butene, vinyl glycidyl ether, vinyl trimethylsilyl ether, and the like.

Examples of other structural units include structural units represented by the following formulas (5-1) to (5-12) (hereinafter, “structural units (III-1) to (III-12)”).

In the above formulas (5-1) to (5-8), R ⁶ is a hydrogen atom or a methyl group.
In the above formulas (5-9) to (5-11), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In the above formula (5-12), R ⁸ represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

Of these, the structural units (III-1), (III-2), (III-4), (III-6), (III-7) or (III-9) are preferred.

[A] When the polymer has other structural units, the upper limit of the content ratio of the other structural units is preferably 50 mol%, preferably 40 mol% with respect to all the structural units constituting the [A] polymer. Is more preferable, 30 mol% is further more preferable, and 28 mol% is especially preferable. As a minimum of the above-mentioned content rate, 1 mol% is preferred, 5 mol% is more preferred, 10 mol% is still more preferred, and 15 mol% is especially preferred. By setting the content ratio of other structural units in the above range, the difference in solubility between the exposed portion and the unexposed portion can be further improved, and the resolution and the remaining film property of the unexposed portion are further improved. be able to.

[A] The lower limit of the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is preferably 2,000, more preferably 4,000, still more preferably 6,000, 000 is particularly preferable, 20,000 is further particularly preferable, and 40,000 is most preferable. The upper limit of Mw is preferably 300,000, more preferably 200,000, still more preferably 100,000, and particularly preferably 80,000. [A] By making Mw of a polymer into the said range, the difference of the solubility of an exposed part and an unexposed part can be improved more, and resolution and the remaining film property of an unexposed part are improved more. be able to.

[A] The upper limit of the ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is preferably 5, more preferably 3, and even more preferably 2.5. The lower limit of the ratio is usually 1, preferably 1.5 and more preferably 1.8.

Mw and Mn of the polymer in this specification are values measured using gel permeation chromatography (GPC) under the following conditions.
GPC equipment: “HLC-8220-GPC” by Tosoh Corporation
GPC column: Tosoh Corporation's “TSK-M” and “TSK2500” connected in series Column temperature: 40 ° C.
Developing solvent: N, N-dimethylformamide Flow rate: 0.5 mL / min Sample concentration: 0.01% by mass
Sample injection volume: 20 μL
Detection method: Refractive index method Standard substance: Monodispersed polystyrene

[A] The lower limit of the content of the polymer is preferably 50% by mass, more preferably 70% by mass, still more preferably 75% by mass, and 80% by mass with respect to the total solid content of the radiation-sensitive resin composition. % Is particularly preferred. As an upper limit of the said content, 99 mass% is preferable, 97 mass% is more preferable, and 95 mass% is further more preferable. The “total solid content” of the radiation-sensitive resin composition refers to all components other than the [C] solvent. [A] A polymer may use 1 type (s) or 2 or more types.

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized by a known method, for example, by polymerizing a monomer giving each structural unit in a suitable solvent using a radical polymerization initiator or the like.

<[B] Compound>
[B] A compound contains a cation (Y) and an anion (X).

(Cation)
The cation (Y) is a radiation-sensitive cation. The “radiation sensitive cation” means a cation that decomposes upon irradiation with radiation.

As the cation (Y), a radiation-sensitive onium cation is preferable. Examples of the onium atom in the radiation-sensitive onium cation include an oxygen atom, a nitrogen atom, a phosphorus atom, a sulfur atom, an arsenic atom, a selenium atom, a tellurium atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a sulfur atom or an iodine atom is preferable.

The cation (Y) may be monovalent or divalent, but monovalent is preferable. Examples of the monovalent cation (Y) include a first cation represented by the following formula (T-1) (hereinafter also referred to as “cation (Y1)”), and a cation represented by the following formula (T-2). 2 cations (hereinafter also referred to as “cation (Y2)”), a third cation represented by the following formula (T-3) (hereinafter also referred to as “cation (Y3)”), or a combination thereof.

In the formula (T-1), R ^a1 and R ^a2 are each independently a monovalent organic group having 1 to 20 carbon atoms. k1 is an integer of 0 to 5. When k1 is 1, R ^a3 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k2 is 2 or more, the plurality of R ^a3 are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, or a plurality of R ^a3 R ^a3 represents a part of a ring structure having 4 to 20 ring members which is constituted together with the carbon chain to which they are bonded to each other. t1 is an integer of 0 to 3.

In the above formula (T-2), k2 is an integer of 0 to 7. When k2 is 1, R ^a4 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k1 is 2 or more, the plurality of R ^a4 are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, or a plurality of R ^a4 R ^a4 represents a part of a ring structure having 4 to 20 ring members that is constituted together with the carbon chain to which they are bonded together. k3 is an integer of 0-6. When k3 is 1, R ^a5 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k3 is 2 or more, the plurality of R ^a5 are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, a halogen atom, or a plurality of R ^a5 R ^a5 represents a part of a ring structure having 3 to 20 ring members constituted together with the carbon chain to which they are bonded to each other. r is an integer of 0 to 3. R ^a6 is a single bond or a divalent organic group having 1 to 20 carbon atoms. t2 is an integer of 0-2.

In the above formula (T-3), k4 is an integer of 0 to 5. When k4 is 1, R ^a7 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k4 is 2 or more, the plurality of ^Ra7s are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, R ^a7 represents a part of a ring structure having 4 to 20 ring members which is constituted together with the carbon chain to which they are bonded to each other. k5 is an integer of 0 to 5. When k5 is 1, R ^a8 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k5 is 2 or more, the plurality of R ^a8 are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, or a plurality of R ^a8 R ^a8 represents a part of a ring structure having 4 to 20 ring members which is constituted together with the carbon chain to which they are bonded to each other.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^a1 to R ^a5 and R ^a7 and R ^a8 include the same groups as the organic groups exemplified as R ^{2 in the} above formula (1). It is done. Examples of the divalent organic group represented by R ^a6 include groups obtained by removing one hydrogen atom from a monovalent organic group having 1 to 20 carbon atoms exemplified as R ^{2 in the} above formula (1). It is done. R ^a6 is particularly preferably a single bond or a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

R ^{a3 in the} above formula (T-1) or R ^{a4 in the} above formula (T-2) is an ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl. Group, t-butyl group, halogen atom, —OR ′, —NR ′ ₂ or —SR ′ is preferable. R ′ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. By using R ^{a3 of the} above formula (T-1) or R ^a4 of the above formula (T-2) as the above group, the resolution of the radiation-sensitive resin composition and the remaining film property of the unexposed portion can be further improved. Can be improved.

In the formula (T-1), k1 is preferably 1 or more. As t1, 0 or 1 is preferable, and 0 is more preferable. In formula (T-2), k2 is preferably 1 or more. k3 is preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0. r is preferably 2 or 3, more preferably 2. t2 is preferably 0 or 1, and more preferably 1. In the formula (Z-3), k4 + k5 is preferably 1 or more.

When k1 in the formula (T-1) is 1 or more, at least one of R ^a1 and R ^{a2 in} the formula (T-1) is preferably a substituted or unsubstituted aryl group, and a substituted aryl group It is more preferable that Thus, when 2 or more, preferably 3 of the aromatic rings in the cation (Y1) have a substituent, ΔE can be further reduced. As a result, the resolution and unresolved properties of the radiation-sensitive resin composition can be reduced. The remaining film property of the exposed part can be further improved. Preferred examples of the substituent for the aryl group include the groups exemplified as R ^{a3 in} the above formula (T-1).

Examples of the cation (Y) include cations represented by the following formulas (6-1-1) to (6-1-6) (hereinafter referred to as “cations (Y1-1) to (Y1-)” as the cation (Y1). 6) ")) etc.
Examples of the cation (Y2) include cations represented by the following formulas (6-2-1) and (6-2-2) (hereinafter also referred to as “cations (Y2-1), (Y2-2)”) and the like. ,
Examples of the cation (Y3) include cations represented by the following formulas (6-3-1) to (6-3-3) (hereinafter, “cations (Y3-1) to (Y3-3)”).

In the above formulas (6-1-1) to (6-1-6), R ^A each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^B is each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms. Each R ^C is independently a halogen atom, —NR ′ ₂ or —SR ′. R ′ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.
In the above formulas (6-2-1) and (6-2-2), R ^D is each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.
In the above formulas (6-3-1) to (6-3-3), R ^E each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.

The cation (Y) is preferably a cation (Y1-1), (Y1-2), (Y1-3), (Y1-4) or (Y1-5) or a cation (Y2-2).

As a minimum of content of cation (Y), 1 mass part is preferred to 3 mass parts of [A] polymer, 3 mass parts are more preferred, and 4 mass parts are still more preferred. As an upper limit of the said content, 40 mass parts is preferable, 30 mass parts is more preferable, and 20 mass parts is further more preferable.

(Anion)
The anion (X) may be monovalent or divalent, but monovalent is preferable.

Examples of the anion (X) include sulfonate anions such as trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, nonafluorobutanesulfonate anion, methanesulfonate anion, cyclohexanesulfonate anion, and benzenesulfonate anion;
Halide anions such as fluoride anion, chloride anion, bromide anion, iodo anion;
Carboxylate anions such as formate anion, acetate anion, propionate anion;
Imide anions such as bis (trifluoromethylcarbonyl) imide anion and bis (trifluoromethylsulfonyl) imide anion;
A hydrogen carbonate anion, a hydrogen sulfate anion, etc. are mentioned.

The anion (X) forms an acid (hereinafter also referred to as “acid (P)”) together with the proton when a proton is generated from the cation (Y) by decomposition by irradiation of radiation.

The upper limit of the molecular volume of the acid (P) is 2.00 × 10 ⁻²⁸ m ³ , preferably 1.70 × 10 ⁻²⁸ m ^3, more preferably 1.40 × 10 ⁻²⁸ m ^3. 10 × 10 ⁻²⁸ m ³ is more preferable, and 0.90 × 10 ⁻²⁸ m ³ is particularly preferable. The lower limit of the molecular volume is preferably 0.10 × 10 ⁻²⁸ m ^3, more preferably 0.20 × 10 ⁻²⁸ m ^3, still more preferably 0.25 × 10 ⁻²⁸ m ³ , and 0.40 × 10 ⁻²⁸ m ³ is particularly preferred. By making the molecular volume of acid (P) into the said range, the resolution of the said radiation sensitive resin composition and the remaining film property of an unexposed part can be improved more.

As the anion (X), a sulfonate anion, a halide anion or a hydrogen carbonate anion is preferable, and a trifluoromethanesulfonate anion, a bromide anion or a hydrogen carbonate anion is more preferable.

As a minimum of content of anion (X), 0.1 mass part is preferred to 100 mass parts of [A] polymer, 1 mass part is more preferred, and 2 mass parts is still more preferred. As an upper limit of the said content, 30 mass parts is preferable, 20 mass parts is more preferable, and 10 mass parts is further more preferable.

[B] The content of the compound, that is, the total content of the cation (Y) and the anion (X) is preferably more than 5 parts by mass, more than 6 parts by mass with respect to 100 parts by mass of the polymer (A). Is more preferably 7 parts by mass or more, and particularly preferably 8 parts by mass or more. As said content, 50 mass parts or less are preferable, 40 mass parts or less are more preferable, 30 mass parts or less are more preferable, and 20 mass parts or less are especially preferable. By making content of a [B] compound into the said range, the resolution of the said radiation sensitive resin composition and the remaining film property of an unexposed part can be improved more. [B] A compound can use 1 type (s) or 2 or more types.

<Relationship between [A] polymer and [B] compound>
[A] For the group (I) in the polymer and the cation (Y) and the anion (X) in the [B] compound, the stabilization energy (ΔE) obtained by the following formula (A) by the density functional method is 0 kJ / Mol or less.
Stabilization energy (ΔE) = (sum of total energies of group (I), cation (Y) and anion (X) when group (I) and anion (X) interact) — (group (I) Sum of all energies of group (I), cation (Y) and anion (X) when anion (X) does not interact) (A)
That is, ΔE is a value per 1 mol of the group (I) of the stabilization energy (kJ) due to the interaction.

“The group (I) and the anion (X) are interacting” means that the anion (X), for example, represents a hydrogen atom of —OH in the group (I) of the polymer (A) and a hydrogen bond. It means that it is formed. “The group (I) and the anion (X) do not interact” means, for example, that the anion (X) does not form a hydrogen bond and has an electrostatic interaction with the cation (Y). It means that.

When both the anion (X) and the cation (Y) are monovalent, ΔE is the group (I) in the [A] polymer in the equilibrium formula represented by the following formula (2) and the cation in the [B] compound. (Y) and anion (X) are obtained by subtracting the sum of the total energies of the substance on the left side from the sum of the energies of the substance on the right side obtained by the density functional method.

In said formula (2), R < ¹ >, R < ² > and * are synonymous with said formula (1). X ⁻ is the monovalent anion (X). Y ⁺ is the monovalent cation (Y).

ΔE can be calculated by quantum chemical calculation (for example, “GAUSSIAN09 program” of GAUSSIAN Inc., B3LYP / 6-31G (d) level or B3LYP / LanL2DZ level). ΔE means stabilization energy, and the smaller the value (the larger the absolute value in the case of a negative value), the closer the equilibrium of the above formula (2) is to the right side.

The upper limit of ΔE is 0 kJ / mol, preferably −5 kJ, more preferably −10 kJ / mol, further preferably −15 kJ / mol, and particularly preferably −20 kJ / mol. The lower limit of ΔE is preferably −50 kJ / mol, and preferably −30 kJ / mol. By setting ΔE within the above range, the resolution of the radiation-sensitive resin composition and the remaining film property of the unexposed portion can be further improved.

<[C] solvent>
The radiation-sensitive resin composition usually contains a [C] solvent. [C] The solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the [A] polymer, the [B] compound, and other optional components optionally contained.

[C] Examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

Examples of the alcohol solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec -Monoalcohol solvents such as heptadecyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvent include 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, Linear ketone solvents such as di-iso-butyl ketone and trimethylnonanone;
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone;
Examples include 2,4-pentanedione, acetonylacetone, acetophenone, and the like.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, i-pentyl acetate, sec Acetate solvents such as pentyl, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Polyhydric alcohol partial ether acetate solvents such as acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
Carbonate solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate;
Lactone solvents such as γ-butyrolactone and δ-valerolactone;
Diethyl acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl acetoacetate, ethyl acetoacetate, methyl lactate, ethyl lactate N-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of hydrocarbon solvents include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene, n-amylnaphthalene Group hydrocarbon solvents and the like.

Among these, alcohol solvents, ketone solvents and / or ester solvents are preferable, monoalcohol solvents, polyhydric alcohol partial ether solvents, cyclic ketone solvents and / or polyhydric alcohol partial ether acetate solvents. More preferred are tetrahydrofurfuryl alcohol, propylene glycol monomethyl ether, cyclohexanone and / or propylene glycol monomethyl ether acetate. [C] 1 type (s) or 2 or more types can be used for a solvent.

<Other optional components>
Examples of other optional components include a second polymer other than the [A] polymer (hereinafter also referred to as “[F] polymer”), a low molecular compound, a sensitizer, and the like.

[[F] polymer]
[F] The polymer is a polymer other than the [A] polymer. As the [F] polymer, for example, a polymer having no structural unit (I) and having a structural unit (II), and having no structural unit (I), the fluorine atom content is higher than that of the [A] polymer. A polymer etc. are mentioned. The radiation sensitive resin composition can form a resist film suitable for the immersion exposure method by further containing a polymer having a high fluorine atom content.

Examples of the [F] polymer include polyhydroxystyrene, polar group-containing poly (meth) acrylate, polyethylene glycol, epoxy resin, and copolymers thereof from the viewpoint of improving developability and adhesion. . Moreover, a leveling agent, a striation inhibitor, etc. can also be used.

[Low molecular compounds]
The low molecular weight compound is a compound other than a polymer, for example, a compound having a molecular weight or a composition formula weight of 500 or less, preferably 400 or less. Examples of the low molecular compound include a surfactant, an acid diffusion controller, and an ether compound.

(Surfactant)
Surfactants have the effect of improving coatability, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. Nonionic surfactants such as stearate; commercially available products include KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, Talkem Products Co., Ltd.), Megafuck F171, F173 (above, DIC Corporation), Florard FC430, FC431 (Sumitomo 3M Co., Ltd.), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( As mentioned above, Asahi Glass Co., Ltd.), FTX-218, NBX-15 (Neos Co., Ltd.) and the like can be mentioned.

(Acid diffusion control agent)
The acid diffusion controlling agent controls the diffusion phenomenon in the resist film of the acid generated from the [B] compound or the like by exposure, and has an effect of suppressing an undesirable chemical reaction in the non-exposed region. In addition, the storage stability of the radiation-sensitive resin composition is further improved, and the resolution as a resist material is further improved. Furthermore, a change in the line width of the resist pattern due to fluctuations in the holding time from exposure to development processing can be suppressed, and a resist material having excellent process stability can be obtained.

Examples of the acid diffusion controller include amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

Examples of the amine compound include monoalkylamines such as n-hexylamine;
Dialkylamines such as di-n-butylamine;
Trialkylamines such as triethylamine and tri-n-pentylamine;
Aromatic amines such as aniline;
Ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine and the like;
Polyamine compounds such as polyethyleneimine and polyallylamine;
Examples thereof include polymers such as dimethylaminoethylacrylamide.

Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. It is done.

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like.

Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N- (undecan-1-ylcarbonyloxyethyl) morpholine; pyrazine, pyrazole and the like. .

Moreover, a compound having an acid dissociable group can also be used as the nitrogen-containing compound. Examples of the nitrogen-containing compound having an acid dissociable group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2- Phenylbenzimidazole, N- (t-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine, Examples thereof include Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine and the like.

Further, as the acid diffusion controlling agent, a photodegradable base that is sensitized by exposure can also be used. Examples of the photodegradable base include a compound having a radiation-sensitive cation and a weak acid anion. The photodegradable base exhibits acid diffusion controllability due to its basicity in the unexposed area, but loses acid diffusion controllability in the exposed area because it is decomposed by exposure and decreases in basicity. Examples of the photodegradable base include triphenylsulfonium salicylate, triphenylsulfonium 10-camphor sulfonate, and the like.

(Ether compound)
When the radiation-sensitive resin composition contains an ether compound, the ether compound and the cation (Y) of the [B] compound interact, and the group (I) and the anion (X ) Will be promoted more.

Examples of the ether compound include dialiphatic ethers such as dibutyl ether and dicyclohexyl ether;
Aromatic-containing ethers such as butoxybenzene, butoxynaphthalene, dibutoxynaphthalene, diphenyl ether;
And cyclic ethers such as oxetane, tetrahydrofuran, tetrahydropyran, and di (3-ethyloxetane-3-ylmethyl) ether.

[Sensitizer]
The sensitizer absorbs radiation and enters an electronically excited state, and electron transfer, energy transfer, and the like can be performed from the sensitizer in the electronically excited state to the cation (Y) of the [B] compound. It is a substance. The said radiation sensitive resin composition can improve a sensitivity more by containing a sensitizer. The form of inclusion of the sensitizer in the radiation-sensitive resin composition may be a low molecular compound form (hereinafter referred to as “sensitizer” as appropriate), or a form incorporated in part of the polymer [A]. Both of these forms may be used.

Examples of the sensitizer include compounds having an absorption wavelength in the region of 350 nm to 450 nm.

Examples of the sensitizer include naphthalene, anthracene, phenanthrene, naphthacene, pyrene, perylene, triphenylene, 9,10-dibutoxyanthracene, 9,10-diethoxyanthracene, 3,7-dimethoxyanthracene, and 9,10-dipropyl. Polynuclear aromatics such as oxyanthracene;
Thiazoles such as benzothiazole;
Xanthenes such as fluorescein, eosin, erythrosine, rhodamine B, rose bengal;
Xanthones such as xanthone, thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone;
Cyanines such as thiacarbocyanine, oxacarbocyanine;
Merocyanines such as merocyanine and carbomerocyanine;
Rhodocyanines;
Oxonols;
Thiazines such as thionine, methylene blue and toluidine blue;
Acridines such as acridine, acridine orange, chloroflavin, acriflavine;
Acridones such as acridone, 10-butyl-2-chloroacridone;
Anthraquinones such as anthraquinone;
Squariums such as squalium;
Styryls;
Base styryls such as 2- [2- [4- (dimethylamino) phenyl] ethenyl] benzoxazole;
7-diethylamino-4-methylcoumarin, 7-hydroxy-4-methylcoumarin, 2,3,6,7-tetrahydro-9-methyl-1H, 5H, 11H [l] benzopyrano [6,7,8-ij] And coumarins such as quinolizine-11-non.

When the said radiation sensitive resin composition contains another arbitrary component, as an upper limit of content of another arbitrary component, 20 mass parts is preferable with respect to 100 mass parts of [A] polymers, and 15 mass parts Is more preferable, and 10 mass parts is further more preferable. As a minimum of the above-mentioned content, it is 0.01 mass part, for example.

<Method for preparing radiation-sensitive resin composition>
In the radiation sensitive resin composition, for example, the [A] polymer, the [B] compound, the [C] solvent, and other optional components as necessary are mixed in a predetermined ratio, and preferably, the obtained mixture is mixed. It can be prepared by filtering with a membrane filter having a pore size of about 1 μm. The lower limit of the solid content concentration of the radiation-sensitive resin composition is preferably 0.1% by mass, more preferably 1% by mass, further preferably 5% by mass, particularly preferably 10% by mass, and further 15% by mass. Preferably, 20% by mass is most preferable. The upper limit of the solid content concentration is preferably 50% by mass, more preferably 40% by mass, still more preferably 35% by mass, and particularly preferably 30% by mass. The “solid content concentration” of the radiation-sensitive resin composition refers to the concentration (% by mass) of all components other than the [C] solvent.

<Resist pattern formation method>
In the resist pattern forming method, a step of coating the radiation-sensitive resin composition directly or indirectly on a substrate (hereinafter, also referred to as “coating step”) and a resist film formed by the coating step are exposed. And a step of developing the exposed resist film (hereinafter also referred to as “developing step”). Hereinafter, each step will be described.

According to the resist pattern forming method, since the radiation-sensitive resin composition described above is used, a fine pattern can be formed even in a non-chemical amplification type, and an exposed portion and an unexposed portion The difference in alkali solubility with the resist pattern can be improved, and a resist pattern with high resolution and a large residual film ratio in the unexposed area can be formed. Hereinafter, each step will be described.

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

Examples of the substrate include conventionally known substrates such as a silicon wafer, silicon dioxide, and a wafer coated with aluminum. Further, for example, an organic or inorganic antireflection film disclosed in Japanese Patent Publication No. 6-12452 and Japanese Patent Application Laid-Open No. 59-93448 may be formed on the substrate. Examples of the coating method include spin coating, spin coating, and roll coating. After coating, pre-baking (PB) may be performed as needed to volatilize the solvent in the coating film. As a minimum of the temperature of PB, 60 degreeC is preferable and 80 degreeC is more preferable. As an upper limit of the said temperature, 140 degreeC is preferable and 120 degreeC is more preferable. The lower limit of the PB time is preferably 5 seconds, and more preferably 10 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. As a minimum of the average thickness of the resist film formed, 10 nm is preferable and 20 nm is more preferable. As an upper limit of the average thickness, 1,000 nm is preferable, and 500 nm is more preferable.

[Exposure process]
In this step, the resist film formed by the coating step is exposed. This exposure is performed by irradiating exposure light through a photomask (in some cases through an immersion medium such as water). As exposure light, for example, visible light, ultraviolet light, deep ultraviolet light such as ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), extreme ultraviolet light (EUV), etc. And electromagnetic waves such as X-rays and γ-rays; charged particle beams such as electron beams and α-rays. Among these, ultraviolet rays, far ultraviolet rays, EUV or electron beams are preferable.

[A] When the polymer has the structural unit (II) and has an acid-dissociable group, it is preferable to perform post-exposure baking (PEB) after the exposure. By performing PEB, the dissociation reaction of the acid-dissociable group by the acid generated from the [B] compound or the like by exposure can be promoted in the exposed portion of the resist film. The difference in solubility can be further improved. As a minimum of the temperature of PEB, 50 ° C is preferred, 80 ° C is more preferred, and 100 ° C is still more preferred. As an upper limit of the said temperature, 180 degreeC is preferable and 130 degreeC is more preferable. 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.

[A] When the polymer does not have the structural unit (II) and does not have an acid-dissociable group, the PEB is not performed and can be omitted.

[Development process]
In this step, the exposed resist film is developed. Thereby, a predetermined resist pattern can be formed. After development, it is common to wash with water or a rinse solution such as alcohol and then dry. The development method in the development step may be alkali development or organic solvent development, but alkali development is preferred.

In the case of alkaline development, examples of the developer used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-. Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1 , 5-diazabicyclo- [4.3.0] -5-nonene and the like, an alkaline aqueous solution in which at least one kind of alkaline compound is dissolved. Among these, a TMAH aqueous solution is preferable, and a 2.38 mass% TMAH aqueous solution is more preferable.

In the case of organic solvent development, examples of the developer include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, and other organic solvents, and solvents containing the above organic solvents. As said organic solvent, the 1 type (s) or 2 or more types of the solvent enumerated as the [C] solvent of the above-mentioned radiation sensitive resin composition are mentioned, for example. Among these, an ester solvent or a ketone solvent is preferable. As the ester solvent, an acetate solvent is preferable, and n-butyl acetate is more preferable. The ketone solvent is preferably a chain ketone, more preferably 2-heptanone. As a minimum of content of the organic solvent in a developing solution, 80 mass% is preferred, 90 mass% is more preferred, 95 mass% is still more preferred, and 99 mass% is especially preferred. Examples of components other than the organic solvent in the developer include water and silicone oil.

As a developing method, for example, a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (dip method), a method in which the developer is raised on the surface of the substrate by surface tension and is left stationary for a certain time (paddle method) ), A method of spraying the developer on the substrate surface (spray method), a method of continuously applying the developer while scanning the developer coating nozzle on the substrate rotating at a constant speed (dynamic dispensing method) Etc.

Examples of the pattern formed by the resist pattern forming method include a line and space pattern and a hole pattern.

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples. The physical property values in this example were measured by the following methods.

[Mw and Mn of polymer]
Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) method under the following conditions.
GPC equipment: “HLC-8220-GPC” by Tosoh Corporation
GPC column: Tosoh Corporation's “TSK-M” and “TSK2500” connected in series Column temperature: 40 ° C.
Developing solvent: N, N-dimethylformamide Flow rate: 0.5 mL / min Sample concentration: 0.01% by mass
Sample injection volume: 20 μL
Detection method: Refractive index method Standard substance: Monodispersed polystyrene

[ ¹ H-NMR measurement]
Using a nuclear magnetic resonance apparatus (“JNM-ECS 400” manufactured by JEOL Ltd.) and using heavy dimethyl sulfoxide as a measurement solvent, an analysis is performed to determine the content (mol%) of each structural unit in each polymer. went.

<[A] Synthesis of polymer>
The compounds (M-1) to (M-7) used for polymer synthesis are shown below.

[Synthesis Example 1] (Synthesis of polymer (A-1))
In a 100 mL three-necked flask, 13.68 g (80 mol%) of the compound (M-1) and 1.32 g (20 mol%) of the compound (M-2) are dissolved in 15 g of tetrahydrofuran (THF), and a radical polymerization initiator is dissolved. Azobisisobutyronitrile (AIBN) 0.52 g (5 mol% based on the total monomers) was added to prepare a monomer solution. Subsequently, nitrogen bubbling was performed for 15 minutes, and then the mixture was heated to 80 ° C. with stirring. The polymerization reaction was carried out for 4 hours by setting the time when the solution reached 61 ° C. as the polymerization start time. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water and cooled to 30 ° C. or lower, and the polymerization reaction solution cooled in 400 g of n-hexane was added, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 100 g of n-hexane, filtered and dried at 50 ° C. overnight to synthesize a white powdery polymer (A-1) (13.4 g, yield). Rate 89%). Mw of the polymer (A-1) was 43,200, and Mw / Mn was 2.00. As a result of ¹ H-NMR analysis, the content ratio of the structural unit derived from (M-1) and the structural unit derived from (M-2) was 83 mol% and 17 mol%.

[Synthesis Examples 2 to 8] (Synthesis of Polymers (A-2) to (A-8))
Polymers (A-2) to (A-8) were obtained in the same manner as in Synthesis Example 1, except that the types and amounts of monomers shown in Table 1 were used. The total mass of the monomers used was 15.0 g. “-” In Table 1 indicates that the corresponding monomer was not used. The yield (%) of the obtained polymer, Mw, Mw / Mn, and the content ratio (mol%) of each structural unit are shown together in Table 1.

<Preparation of radiation-sensitive resin composition>
The [B] compound, [C] solvent and other optional components used for the preparation of the radiation sensitive resin composition are shown below.

[[B] Compound]
B-1: 4,7-di-n-butoxynaphthyltetrahydrothiophenium trifluoromethanesulfonate B-2: triphenylsulfonium bromide B-3: triphenylsulfonium trifluoromethanesulfonate B-4: diphenyl (4-methoxyphenyl) Sulfonium trifluoromethanesulfonate B-5: Tris (4-methoxyphenyl) sulfonium trifluoromethanesulfonate B-6: Tris (4-t-butylphenyl) sulfonium hydrogen carbonate B-7: (4-phenylthiophenyl) diphenylsulfonium trifluoro Lomethanesulfonate CB-1: 4-n-butoxynaphthyltetrahydrothiophenium nonafluorobutanesulfonate CB-2: Triphenylsulfonium camphor Sulfonate

[[C] solvent]
C-1: Propylene glycol monomethyl ether C-2: Tetrahydrofurfuryl alcohol C-3: Propylene glycol monomethyl ether acetate C-4: Cyclohexanone

[Other optional ingredients]
D-1: Surfactant (“FTX-218” from Neos Co., Ltd.)
D-2: Surfactant ("NBX-15" from Neos Co., Ltd.)

<Calculation of stabilization energy (ΔE)>
Calculation of the stabilization energy (ΔE) in the equilibrium equation represented by the above formula (2) was performed as follows.

As the substance having the group (I), 4- (A) of the compound (M-1) which is a monomer (hereinafter also referred to as “monomer (A)”) that gives the structural unit (I) of the [A] polymer. (1-hydroxy-1-trifluoromethyl-2,2,2-trifluoroethane-1-yl) styrene, the cation (Y) and the anion (X) as the radiation-sensitive cation contained in the compound [B] and Anion.

Stabilization energy (ΔE) between monomer (A) and [B] compound by quantum chemistry calculation (B3LYP / 6-31G (d) level or B3LYP / LanL2DZ level, “GAUSSIAN09 program” of GAUSSIAN Inc.) ) Is calculated based on the energy value when the monomer (A) and the anion (X) are associated to form the most stable structure, and the energy value when the isolated structure of the cation (Y) has the most stable structure. From the sum of the above, the energy value when the anion (X) and the cation (Y) are associated to form the most stable structure and the energy value when the monomer (A) is the most stable structure in the isolated system It was done as a reduction of the sum.

Also, the molecular volume of the acid (P) formed from the anion (X) and the proton was calculated using the above quantum chemistry calculation.

The stabilization energy (ΔE) value thus calculated (unit: kJ / mol) and the molecular volume value (unit: 10 ⁻²⁸ m ³ ) of the acid (P) for the [B] compound are shown below. It shows in Table 2.

[Example 1-1]
[A] 100 parts by mass of (A-1) as a polymer, 21.3 parts by mass of (B-1) as a [B] compound, [C] 262.5 parts by mass of (C-1) as a solvent, and (C-2) 65.6 parts by mass and (D-1) 0.1 part by mass as other optional components are uniformly mixed at 25 ° C., and foreign matters are removed by a membrane filter having a pore diameter of 1 μm, and radiation sensitivity is obtained. A resin composition (J1-1) was prepared. The solid content concentration of the radiation sensitive resin composition (J1-1) was 27.0% by mass.

[Examples 1-2 to 1-13 and Comparative Examples 1-1 and 1-2]
Radiation sensitive resin compositions (J1-2) to (J1-13) and (CJ1-1) in the same manner as in Example 1-1 except that the components of the types and blending amounts shown in Table 3 below were used. And (CJ1-2) were prepared.

<Evaluation>
[Alkali solubility]
The prepared radiation sensitive resin composition was spin-coated on a 4-inch silicon wafer, and then heated at 100 ° C. for 3 minutes using a hot plate to form a uniform resin coating having a thickness of about 5 μm. Subsequently, it was immersed in an aqueous solution of tetramethylammonium hydroxide (TMAH) having a concentration of 2.38% by mass at 23 ° C. The time (dissolution time (T1)) in which the resin coating film was completely dissolved was measured.
Also, for the composition obtained without adding the [B] compound in the preparation of the radiation sensitive resin composition, the time when the resin coating film was completely dissolved by the same method as above (dissolution time (T2)). Was measured.
The value of the ratio of the dissolution time (T1) to the dissolution time (T2) can be used as an index indicating the difference in alkali solubility between the exposed portion and the unexposed portion.
Regarding alkali solubility, when the value of dissolution time (T1) / dissolution time (T2) is 7 or more, it is “A” (good), and when it is 2 or more and less than 7, “B” (somewhat poor) and less than 2 In the case of, it was evaluated as “C” (defective).
The evaluation results are shown in Table 3 below.

From the results of Table 3, it is considered that according to the radiation-sensitive resin composition of the example, the difference in alkali solubility between the exposed part and the unexposed part can be improved. On the other hand, in the radiation sensitive resin composition of the comparative example, the difference in alkali solubility between the exposed part and the unexposed part remains low.

<Formation of resist pattern>
[Examples 2-1 to 2-5]
The prepared radiation sensitive resin compositions (J1-1), (J1-8) to (J1-10) and (J1-12) were spin-coated on a 4-inch silicon wafer, and then a hot plate was used. And heated at 100 ° C. for 3 minutes to form a uniform resin film having a thickness of about 5 μm. Next, using an aligner (“Sus Microtec“ MA-200 ”), the resin coating film is irradiated with UV light from a high-pressure mercury lamp through a pattern mask so that the exposure dose at a wavelength of 365 nm is 300 mJ / cm ^2. did. Next, the resin coating film was immersed and developed at 23 ° C. for 60 seconds using a 2.38% by mass TMAH aqueous solution, and then the developed resin coating film was washed with ultrapure water for 60 seconds, The resist pattern was formed by air drying.

<Evaluation>
Using the resist pattern thus formed, the resolution of the radiation-sensitive resin composition and the remaining film property of the unexposed part were evaluated by the following methods. The evaluation results are shown in Table 4 below.

[Resolution]
The resist pattern was observed with a microscope ("MHL110" from Olympus Co., Ltd.), and the pattern size (unit: μm) of the resolved minimum pattern was defined as resolution.

[Remaining film properties of unexposed areas]
The average thickness of the resist film in the unexposed area was measured before and after development when the resist pattern was formed, and the remaining film ratio (%) was calculated by (thickness after development / thickness before development) × 100. The remaining film property of the unexposed area is “A” (good) when the remaining film ratio is 90% or more, “B” (slightly defective) when 80% or more and less than 90%, and less than 80%. Was evaluated as "C" (bad).

From the results of Table 4, it can be seen that the radiation-sensitive resin compositions of the examples are excellent in resolution and remaining film properties of unexposed portions.

<Preparation of radiation-sensitive resin composition>
[Example 3-1]
[A] 100 parts by mass of (A-8) as a polymer, 5.0 parts by mass of (B-5) as a [B] compound, [C] 484.4 parts by mass of (C-3) as a solvent, and (C-4) 323.0 parts by mass and (D-2) 0.1 part by mass as other optional components were uniformly mixed at 25 ° C., and foreign matter was removed with a polytetrafluoroethylene membrane filter having a pore diameter of 0.2 μm. Then, a radiation sensitive resin composition (J2-1) was prepared. The solid content concentration of the radiation sensitive resin composition (J2-1) was 12.0% by mass.

[Examples 3-2 to 3-5]
Radiation sensitive resin compositions (J2-2) to (J2-5) were prepared in the same manner as in Example 3-1, except that the components of the types and blending amounts shown in Table 5 below were used.

<Evaluation>
[Residual film rate]
A 12-inch silicon wafer is coated with a radiation-sensitive resin composition using a photoresist coating and developing apparatus (“CLEAN TRACK ACT-12” manufactured by Tokyo Electron Ltd.), and then heated at 120 ° C. for 60 seconds. As a result, a radiation-sensitive resin composition film having a thickness of 340 nm was formed. Next, using the above photoresist coating and developing apparatus, paddle development was performed for 60 seconds with an aqueous 2.38 mass% tetramethylammonium hydroxide solution, and the film thickness was measured after spin-drying at 1,500 rpm for 30 seconds. The percentage of the remaining film thickness after development relative to the film thickness before development was defined as the remaining film ratio (%).

[sensitivity]
An underlayer antireflection film (“DUV42” from Brewer Science Co., Ltd.) was coated on a 12-inch silicon wafer using the above photoresist coating and developing apparatus, and then heated at 205 ° C. for 60 seconds to form a lower layer having a thickness of 60 nm. An antireflection film was formed. Next, using the photoresist coating and developing apparatus, each radiation sensitive resin composition shown in Table 6 below was applied, and PB was performed at 120 ° C. for 60 seconds. Thereafter, it was cooled at 23 ° C. for 30 seconds to form a resist film having a thickness of 340 nm. Next, using a KrF exposure apparatus (Nikon Corporation's “S210D”), the exposure amount was changed under the best focus condition through a photomask under the optical conditions of NA = 0.75 and σ = 0.75. And exposed. Next, using the photoresist coating and developing apparatus, a paddle development was performed for 60 seconds with a 2.38 mass% tetramethylammonium hydroxide aqueous solution, and spin drying was performed by shaking off at 1500 rpm for 30 seconds to form a resist pattern. For the resist pattern evaluation, a scanning electron microscope (“CG4000” manufactured by Hitachi High-Technologies Corporation) was used.
The exposure amount that can form a line-and-space (1L1S) with a line width of 300 nm in a one-to-one line width was taken as the optimum exposure amount, and this optimum exposure amount was taken as sensitivity.

[Limit resolution]
The minimum dimension of the line and space (1L1S) resolved when exposed at the optimum exposure amount was defined as the limit resolution (nm).

[Pattern top shape]
With respect to the radiation sensitive resin compositions (J2-4) and (J2-5), the pattern top shape was evaluated. The pattern top shape was evaluated as “good” if the upper part of the resist pattern resolved when exposed at the optimum exposure amount was flat, and “top loss” if there was no flat part. Regarding the pattern top shape, the radiation-sensitive resin composition (J2-4) was “top loss” and the radiation-sensitive resin composition (J2-5) was “good”.

[Pattern bottom shape]
The pattern bottom shape was evaluated for the radiation sensitive resin compositions (J2-4) and (J2-5). The pattern bottom shape is evaluated as “good” when there is no resist residue at the interface between the lower part of the resist pattern and the substrate that is resolved when exposed at the optimum exposure amount, and “bottom” when there is resist residue. did. Regarding the pattern bottom shape, the radiation-sensitive resin composition (J2-4) was “bottom”, and the radiation-sensitive resin composition (J2-5) was “good”.

From the results of Table 6, it can be seen that the radiation-sensitive resin compositions of the examples are excellent in the remaining film rate, sensitivity, and limit resolution.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, a fine pattern can be formed even in a non-chemical amplification type. Therefore, according to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, it can overcome the weaknesses of conventional chemically amplified resists, and is suitably used for manufacturing semiconductor devices where further miniaturization is expected in the future. be able to.

Claims

A first polymer having a first structural unit containing a first group represented by the following formula (1);
A radiation sensitive cation;
Containing anions and
The content ratio of the first structural unit in the first polymer is 50 mol% or more,
The molecular volume of the acid formed from the anion and proton is 2.00 × 10 −28 m 3 or less,
The radiation sensitive resin composition whose stabilization energy ((DELTA) E) calculated | required by the following formula (A) by a density functional method is 0 kJ / mol or less.
Stabilization energy (ΔE) = (Sum of all energies of the first group, the radiation-sensitive cation, and the anion when the first group and the anion interact) − (the first group The total energy of the first group, the radiation-sensitive cation, and the anion when the anion and the anion do not interact) (A)

(In the formula (1), R 1 is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R 2 is a hydrogen atom, a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. (It is an organic group. * Represents a site bonded to a portion other than the first group in the first structural unit.)
The radiation-sensitive resin composition according to claim 1, wherein the total content of the radiation-sensitive cation and the anion with respect to 100 parts by mass of the first polymer is more than 5 parts by mass.
The radiation sensitive resin composition according to claim 1 or 2, wherein the first group is bonded to an aromatic ring.
The radiation sensitive resin composition according to claim 1, 2 or 3, wherein the content ratio of the second structural unit containing an acid dissociable group in the first polymer is 20 mol% or less.
The radiation-sensitive cation includes a first cation represented by the following formula (T-1), a second cation represented by the following formula (T-2), and a third cation represented by the following formula (T-3). The radiation-sensitive resin composition according to any one of claims 1 to 4, which is a cation or a combination thereof.

(In the formula (T-1), R a1 and R a2 are each independently a monovalent organic group having 1 to 20 carbon atoms. K1 is an integer of 0 to 5. In this case, R a3 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, and when k1 is 2 or more, a plurality of R a3 are the same or Differently, it is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, or a plurality of R a3 are combined with each other and configured with a carbon chain to which these are bonded. Represents a part of a ring structure having 4 to 20 ring members, and t1 is an integer of 0 to 3.
In the formula (T-2), k2 is an integer of 0 to 7. When k2 is 1, R a4 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k2 is 2 or more, the plurality of R a4 are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, or a plurality of R a4 R a4 represents a part of a ring structure having 4 to 20 ring members that is constituted together with the carbon chain to which they are bonded together. k3 is an integer of 0-6. When k3 is 1, R a5 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k3 is 2 or more, the plurality of R a5 are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, a halogen atom, or a plurality of R a5 R a5 represents a part of a ring structure having 3 to 20 ring members constituted together with the carbon chain to which they are bonded to each other. r is an integer of 0 to 3. R a6 is a single bond or a divalent organic group having 1 to 20 carbon atoms. t2 is an integer of 0-2.
In the formula (T-3), k4 is an integer of 0 to 5. When k4 is 1, R a7 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k4 is 2 or more, the plurality of Ra7s are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, R a7 represents a part of a ring structure having 4 to 20 ring members which is constituted together with the carbon chain to which they are bonded to each other. k5 is an integer of 0 to 5. When k5 is 1, R a8 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom. when k5 is 2 or more, the plurality of R a8 are the same or different and are a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, an amino group, a nitro group, a thiol group, or a halogen atom, or a plurality of R a8 R a8 represents a part of a ring structure having 4 to 20 ring members which is constituted together with the carbon chain to which they are bonded to each other. )
6. The radiation-sensitive resin composition according to claim 5, wherein k1 in the formula (T-1), k2 in the formula (T-2), and k4 + k5 in the formula (T-3) are 1 or more.
The radiation-sensitive cation is the first cation, the second cation or a combination thereof, and R a3 in the formula (T-1) and R a4 in the formula (T-2) are an ethyl group, n- Propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, halogen atom, —OR ′, —NR ′ 2 or —SR ′, and R ′ is The radiation-sensitive resin composition according to claim 6, which is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.
The radiation-sensitive resin composition according to claim 5, 6 or 7, wherein at least one of R a1 and R a2 in the formula (T-1) is a substituted aryl group.
The radiation sensitive resin composition according to any one of claims 1 to 8, further comprising a second polymer other than the first polymer.
Applying the radiation-sensitive resin composition according to any one of claims 1 to 9 directly or indirectly to a substrate;
Exposing the resist film formed by the coating process;
And a step of developing the exposed resist film.