WO2024024692A1

WO2024024692A1 - Active light-sensitive or radiation-sensitive resin composition, resist film, pattern formation method, and electronic device manufacturing method

Info

Publication number: WO2024024692A1
Application number: PCT/JP2023/026882
Authority: WO
Inventors: 洋平石地; 智美高橋; 健志川端; 研由後藤
Original assignee: 富士フイルム株式会社
Priority date: 2022-07-29
Filing date: 2023-07-21
Publication date: 2024-02-01

Abstract

Provided are a resist film, a pattern formation method, an electronic device manufacturing method that includes the pattern formation method, and an active light-sensitive or radiation-sensitive resin composition satisfying the following requirements (1) to (3) and comprising: (A) an onium salt containing an anion whose conjugate acid has a pKa of 2 or greater; and (B) a polymer that is a compound differing from the onium salt (A), the polymer including a repeating unit having an interactive group that interacts with the onium salt (A), and the polymer having a main chain that decomposes when irradiated with active light or radiation. (1) The composition comprises at least one component selected from the group consisting of an antioxidant, a polymerization inhibitor, and a chain transfer agent. (2) The onium salt (A) includes at least one component selected from the group consisting of an anti-oxidizing group, a polymerization terminating group, and a chain transfer group. (3) The polymer (B) includes at least one component selected from the group consisting of an anti-oxidizing group, a polymerization terminating group, and a chain transfer group.

Description

Actinic ray-sensitive or radiation-sensitive resin composition, resist film, pattern forming method, and electronic device manufacturing method

The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, a resist film, a pattern forming method, and an electronic device manufacturing method.

After resists for KrF excimer laser (248 nm), pattern forming methods using chemical amplification have been used to compensate for the decrease in sensitivity due to light absorption. For example, in a positive chemical amplification method, first, a photoacid generator contained in an exposed area is decomposed by light irradiation to generate acid. Then, in the post-exposure bake (PEB) process, etc., the catalytic action of the generated acid converts the alkali-insoluble groups of the resin contained in the actinic ray-sensitive or radiation-sensitive resin composition into alkali-soluble groups. The solubility in the developer is changed by, for example, changing to a base. Thereafter, development is performed using, for example, a basic aqueous solution. Thereby, the exposed portion is removed and a desired pattern is obtained.

Furthermore, a pattern forming method using a polymer whose main chain is cleaved by irradiation with actinic rays or radiation is also known.
For example, Patent Document 1 describes an organic resin composition that contains a polymer whose main chain is cleaved by absorbing deep ultraviolet rays and a polymerization inhibitor, and the content of the polymerization inhibitor is within a specific range. Are listed.
Patent Document 2 describes an ionic compound and a repeating unit having an interactive group that interacts with the ionic group in the ionic compound, and whose main chain is decomposed by irradiation with X-rays, electron beams, or extreme ultraviolet rays. A positive resist composition containing a resin is described.

Japanese Patent Application Publication No. 2020-45471 International Publication No. 2021/153466

Recently, due to the miniaturization of semiconductor devices, the wavelength of exposure light sources has become shorter and the numerical aperture (NA) of projection lenses has become higher. For example, extreme ultraviolet (EUV) and electron beam (EB) ) is also being considered as a pattern forming method using a light source. Under these current circumstances, actinic ray-sensitive or radiation-sensitive resin compositions are required to further improve their performance.

The present invention includes an actinic ray-sensitive or radiation-sensitive resin composition capable of forming a pattern with excellent resolution and excellent LWR (Line Width Roughness) performance, a resist film, a pattern forming method, and the above pattern forming method. An object of the present invention is to provide a method for manufacturing an electronic device.

The present inventors have discovered that the above problem can be solved by the following configuration.

<1>
(A) an onium salt containing an anion whose conjugate acid has a pKa of 2 or more, and
(B) A compound different from the above onium salt (A), containing a repeating unit having an interactive group that interacts with the above onium salt (A), and whose main chain is decomposed by irradiation with actinic rays or radiation. including a polymer;
An actinic ray-sensitive or radiation-sensitive resin composition that satisfies at least one of the following (1) to (3).
(1) The actinic ray-sensitive or radiation-sensitive resin composition contains at least one selected from the group consisting of antioxidants, polymerization inhibitors, and chain transfer agents.
(2) The above onium salt (A) contains at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.
(3) The polymer (B) contains at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.
<2>
The above (1) is satisfied, and at least one selected from the group consisting of the above antioxidant, polymerization inhibitor, and chain transfer agent is a polyhydric phenol compound, an amine compound, a thiol compound, a phosphorus compound, a sugar compound, a nitro compound, and a nitrosol compound. The actinic ray-sensitive or radiation-sensitive resin composition according to <1>, which is at least one selected from the group consisting of compounds.
<3>
At least one selected from the group consisting of the antioxidant, polymerization inhibitor, and chain transfer agent is at least one selected from the group consisting of a polyhydric phenol compound, a thiol compound, and a nitroso compound, <1> or <2> ＞The actinic ray-sensitive or radiation-sensitive resin composition described in ＞.
<4>
At least one selected from the group consisting of the above antioxidant, polymerization inhibitor, and chain transfer agent is a group consisting of a compound represented by the following formula (H-1) and a compound represented by the following formula (H-2). The actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <3>, which is at least one selected from the following.

In formula (H-1), R ^H1 represents a hydrogen atom, a hydroxy group, or an organic group, and R ^H2 to R ^H4 each independently represent a hydrogen atom or an organic group. Adjacent two of R ^H1 to R ^H4 may be bonded to each other to form a ring.
In formula (H-2), R ^H5 represents a hydrogen atom, a hydroxy group, or an organic group, and R ^H6 to R ^H8 each independently represent a hydrogen atom or an organic group. R ^H5 and R ^H6 may be bonded to each other to form a ring. R ^H7 and R ^H8 may be bonded to each other to form a ring.
<5>
An aromatic group that satisfies at least one of the above (2) and (3) and in which at least one selected from the group consisting of the antioxidant group, polymerization termination group, and chain transfer group is substituted with two or more hydroxy groups; Aromatic groups substituted with one or more hydroxy groups and one or more carboxy groups, amino groups, thiol groups, groups containing phosphorus atoms, structures in which two carbon atoms of a carbon-carbon double bond are each substituted with one hydroxy group The actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <4>, which contains at least one selected from the group consisting of a group containing , a nitro group, and a nitroso group.
<6>
At least one selected from the group consisting of the above antioxidant group, polymerization termination group, and chain transfer group is at least one selected from the group consisting of an aromatic group substituted with two or more hydroxy groups, a thiol group, and a nitroso group. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <5>, comprising:
<7>
At least one selected from the group consisting of the above antioxidant group, polymerization termination group, and chain transfer group is a group consisting of a group represented by the following formula (H-1S) and a group represented by the following formula (H-2S) The actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <6>, which is at least one selected from the following.

In formula (H-1S), R ^H1S represents a hydrogen atom, a hydroxy group, or an organic group, and R ^H2S to R ^H4S each independently represent a hydrogen atom or an organic group. Adjacent two of R ^H1S to R ^H4S may be bonded to each other to form a ring. However, at least one hydrogen atom contained in R ^H1S to R ^H4S and a hydrogen atom contained in a ring formed by bonding two adjacent ones of R ^H1S to R ^H4S to each other is removed to form a group. .
In formula (H-2S), R ^H5S represents a hydrogen atom, a hydroxy group or an organic group, and R ^H6S to R ^H8S each independently represent a hydrogen atom or an organic group. R ^H5S and R ^H6S may be combined with each other to form a ring. R ^H7S and R ^H8S may be combined with each other to form a ring. However, hydrogen atoms contained in R ^H5S to R ^H8S , hydrogen atoms contained in the ring formed by combining R ^H5S and R ^H6S , and hydrogen atoms contained in the ring formed by combining R ^H7S and R ^H8S , At least one hydrogen atom is removed to form a group.
<8>
<1> to <7>, wherein the conjugate acid of the anion contained in the onium salt (A) is at least one selected from the group consisting of a phenolic compound, a carboxylic acid, an imidic acid, a sulfonimidic acid, and a thiol compound. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of the above.
<9>
The actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <8>, wherein the onium salt (A) is at least one selected from the group consisting of sulfonium salts and iodonium salts. thing.
<10>
The polymer (B) according to any one of <1> to <9>, wherein the polymer (B) contains a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2). Actinic ray-sensitive or radiation-sensitive resin composition.

In formula (1), X represents a halogen atom. R ⁰ and A ¹ each independently represent a hydrogen atom or an organic group. L ¹ represents -O- or -NR ¹ -. R ¹ represents a hydrogen atom or an organic group. R ⁰ and A ¹ or R ¹ may be bonded to each other to form a ring.
In formula (2), Y represents a hydrogen atom or a hydrocarbon group. A ² represents an organic group.
However, at least one of A ¹ and A ² has an interactive group that interacts with the onium salt (A).
<11>
The repeating unit represented by the above formula (2) is at least one selected from the group consisting of the repeating unit represented by the following formula (2)-1 to the repeating unit represented by the following formula (2)-4. The actinic ray-sensitive or radiation-sensitive resin composition according to <10>.

In formula (2)-1, Y represents a hydrogen atom or a hydrocarbon group. Ar represents an aryl group.
In formula (2)-2, Y represents a hydrogen atom or a hydrocarbon group. L ² represents a single bond or -CO-. R ^a represents a hydrocarbon group.
In formula (2)-3, Y represents a hydrogen atom or a hydrocarbon group. R ^b and R ^c each independently represent a hydrocarbon group. R ^b and R ^c may be combined with each other to form a ring.
In formula (2)-4, Y represents a hydrogen atom or a hydrocarbon group. L ³ represents -O- or -NR ^e -. R ^e represents a hydrogen atom or an organic group. R ^d represents a hydrocarbon group.
<12>
The interactive group that the polymer (B) has and interacts with the onium salt (A) is at least one selected from the group consisting of a hydroxy group, a carboxy group, an imide group, a sulfonimide group, and a thiol group. , the actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <11>.
<13>
The polymer (B) contains a repeating unit having an interactive group that interacts with the onium salt (A),
The actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <12>, wherein the repeating unit has two or more interactive groups that interact with the onium salt (A). thing.
<14>
The actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <13>, wherein the polymer (B) contains a repeating unit represented by the following formula (3).

In formula (3), k represents an integer from 2 to 5. A ³ represents an interactive group that interacts with the above onium salt (A). A plurality of ^A3s may be the same or different. L ⁴ represents a single bond or a connecting group. A plurality of L ⁴ may be the same or different. A plurality of L ⁴ may be bonded to each other to form a ring.
<15>
Any one of <1> to <14>, wherein the polymer (B) contains a repeating unit represented by the following formula (1)-1 and a repeating unit represented by the following formula (3)-1. The actinic ray-sensitive or radiation-sensitive resin composition described in .

In formula (1)-1, X represents a halogen atom. R ^f represents a hydrogen atom or an organic group.
In formula (3)-1, Z ¹ represents a hydroxy group or a carboxy group.
<16>
A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <15>.
<17>
forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of <1> to <15>;
a step of exposing the resist film;
Developing the exposed resist film using a developer containing an organic solvent;
A pattern forming method comprising:
<18>
A method for manufacturing an electronic device, including the pattern forming method according to <17>.

According to the present invention, an actinic ray-sensitive or radiation-sensitive resin composition capable of forming a pattern with excellent resolution and excellent LWR performance, a resist film, a pattern forming method, and an electronic device including the above pattern forming method are provided. We can provide manufacturing methods.

The present invention will be explained in detail below.
Although the description of the constituent elements described below may be made based on typical embodiments of the present invention, the present invention is not limited to such embodiments.
Regarding the notation of groups (atomic groups) in this specification, unless it goes against the spirit of the present invention, the notation that does not indicate substituted or unsubstituted includes groups having a substituent as well as groups having no substituent. do. For example, the term "alkyl group" includes not only an alkyl group without a substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). Furthermore, the term "organic group" as used herein refers to a group containing at least one carbon atom.
Unless otherwise specified, the substituent is preferably a monovalent substituent.

In this specification, the type of substituent, the position of the substituent, and the number of substituents when "may have a substituent" are not particularly limited. The number of substituents may be, for example, one, two, three, or more. Examples of substituents include monovalent nonmetallic atomic groups excluding hydrogen atoms.

The term "actinic rays" or "radiation" as used herein means, for example, the bright line spectrum of a mercury lamp, far ultraviolet rays typified by excimer lasers, extreme ultraviolet rays, X-rays, and electron beams. "Light" in this specification means actinic rays or radiation.
Unless otherwise specified, "exposure" in this specification refers not only to exposure to the bright line spectrum of a mercury lamp, far ultraviolet rays typified by excimer lasers, extreme ultraviolet rays, X-rays, and extreme ultraviolet rays, but also to electron beams and ion beams. This also includes drawing using particle beams such as.
In the present specification, "~" is used to include the numerical values described before and after it as a lower limit value and an upper limit value.
The direction of bonding of the divalent groups described herein is not limited unless otherwise specified. For example, when Y in the compound represented by the formula "X-Y-Z" is -COO-, Y may be -CO-O- or -O-CO- Good too. Further, the above compound may be "X-CO-O-Z" or "X-O-CO-Z".

In this specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and dispersity (also referred to as molecular weight distribution) (Mw/Mn) of the resin are measured using a GPC (Gel Permeation Chromatography) apparatus (HLC-8120GPC manufactured by Tosoh). ) GPC measurement (solvent: tetrahydrofuran, flow rate (sample injection amount): 10 μL, column: Tosoh TSK gel Multipore HXL-M, column temperature: 40°C, flow rate: 1.0 mL/min, detector: differential refractive index Defined as a polystyrene equivalent value determined by a Refractive Index Detector.

In this specification, acid dissociation constant (pKa) refers to pKa in an aqueous solution, and specifically, using the following software package 1, a value based on Hammett's substituent constant and a database of known literature values is calculated. , is a value obtained by calculation. All pKa values described herein are values calculated using this software package.

Software package 1: Advanced Chemistry Development (ACD/Labs) Software V8.14 for Solaris (1994-2007 ACD/Labs).

On the other hand, pKa can also be determined by molecular orbital calculation method. A specific method for this includes a method of calculating H 2 ⁺ dissociation free energy in an aqueous solution based on a thermodynamic cycle. The H ⁺ dissociation free energy can be calculated, for example, by DFT (density functional theory), but various other methods have been reported in the literature, and the method is not limited to this. . Note that there is a plurality of software that can perform DFT, and one example is Gaussian 16.

As mentioned above, pKa in this specification refers to a value obtained by calculating a value based on Hammett's substituent constant and a database of known literature values using software package 1. If calculation is not possible, a value obtained by Gaussian 16 based on DFT (density functional theory) is adopted.
In addition, pKa in this specification refers to "pKa in an aqueous solution" as described above, but if pKa in an aqueous solution cannot be calculated, "pKa in a dimethyl sulfoxide (DMSO) solution" is adopted. It shall be.

In this specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In this specification, the solid content is intended to be a component that forms a resist film, and does not include a solvent. Furthermore, if the component forms a resist film, it is considered to be a solid component even if the component is liquid.

[Actinic ray-sensitive or radiation-sensitive resin composition]
The actinic ray-sensitive or radiation-sensitive resin composition of the present invention is
(A) an onium salt containing an anion whose conjugate acid has a pKa of 2 or more, and
(B) A compound different from the above onium salt (A), containing a repeating unit having an interactive group that interacts with the above onium salt (A), and whose main chain is decomposed by irradiation with actinic light or radiation. including a polymer;
It is an actinic ray-sensitive or radiation-sensitive resin composition that satisfies at least one of the following (1) to (3).
(1) The actinic ray-sensitive or radiation-sensitive resin composition contains at least one selected from the group consisting of antioxidants, polymerization inhibitors, and chain transfer agents.
(2) The above onium salt (A) contains at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.
(3) The polymer (B) contains at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention is typically a resist composition. Hereinafter, the actinic ray-sensitive or radiation-sensitive resin composition of the present invention will also be referred to as a "resist composition."

Hereinafter, first, various components contained in the resist composition of the present invention will be explained.

<(A) Onium salt containing an anion whose conjugate acid has a pKa of 2 or more>
The resist composition of the present invention contains an onium salt (also referred to as "onium salt (A)") containing an anion with a conjugate acid having a pKa of 2 or more.
In the unexposed area of the resist film formed using the resist composition of the present invention, the onium salt (A) and the polymer (B) interact, making it difficult to dissolve in the developer. On the other hand, when exposed to light, the main chain of the polymer (B) decomposes and the interaction between the onium salt (A) and the polymer (B) is canceled, making it easier to dissolve in the developer. In other words, it is thought that the above effect increases the dissolution contrast between the unexposed area and the exposed area of the resist film, resulting in excellent resolution and LWR performance.

The onium salt (A) is preferably at least one selected from the group consisting of sulfonium salts and iodonium salts.

The onium salt (A) contains an anion whose conjugate acid has a pKa of 2 or more. It is preferable that the onium salt (A) contains an anion whose conjugate acid has a pKa of 2 or more because the interaction between the above-mentioned onium salt (A) and the polymer (B) becomes stronger and the dissolution contrast becomes higher.
The pKa of the conjugate acid of the anion contained in the onium salt (A) is 2 or more, preferably 3 or more, and more preferably 4 or more. Furthermore, the pKa of the conjugate acid of the anion contained in the onium salt (A) is preferably 13 or less, more preferably 11 or less, even more preferably 8 or less, and preferably 6 or less. Particularly preferred. pKa is determined by the method described above.

The conjugate acid of the anion contained in the onium salt (A) is preferably at least one selected from the group consisting of phenolic compounds, carboxylic acids, imidic acids, sulfonimidic acids, and thiol compounds; More preferably, it is at least one selected from the group consisting of:

The anions contained in the onium salt (A) include an anion having a group represented by the following formula (An-1), an anion having a group represented by the following formula (An-2), and an anion having a group represented by the following formula (An-3). At least one selected from the group consisting of an anion having a group represented by the following formula (An-4), and an anion having a group represented by the following formula (An-5). It is preferably at least one selected from the group consisting of an anion having a group represented by the following formula (An-1) and an anion having a group represented by the following formula (An-2). preferable.

In formulas (An-1), (An-2), (An-3), (An-4) and (An-5), * represents the bonding position, respectively. In formula (An-5), R ^A1 represents a hydrogen atom or a monovalent organic group.

* in formula (An-1) represents a bonding position, preferably representing a bonding position with an aromatic group.
The anion having a group represented by the formula (An-1) is preferably an anion represented by the following formula (An-1-1).

In formula (An-1-1), Ar ¹ represents an aromatic group.
The aromatic group represented by Ar ¹ in formula (An-1) may be an aromatic hydrocarbon group or an aromatic heterocyclic group, but is preferably an aromatic hydrocarbon group. Ar ¹ is preferably an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms (heteroatoms include, for example, oxygen atom, sulfur atom, nitrogen atom, etc.), It is more preferably an aryl group having 6 to 15 carbon atoms, even more preferably a phenyl group or a naphthyl group, and particularly preferably a phenyl group. The aromatic group represented by Ar ¹ may have a substituent. Preferred examples of the substituent include an alkyl group, a cycloalkyl group, an alkoxy group, and a hydroxy group.

* in formula (An-2) represents a bonding position, preferably representing a bonding position with an aromatic group.
The anion having a group represented by formula (An-2) is preferably an anion represented by formula (An-2-1) below.

In formula (An-2-1), Ar ² represents an aromatic group.
The description, specific examples, and preferred range of Ar ² are the same as Ar ¹ in the above formula (An-1-1). The aromatic group represented by Ar ² may have a substituent. Preferred examples of the substituent include an alkyl group, a cycloalkyl group, an alkoxy group, a hydroxy group, and a thiol group.

Each * in formula (An-3) represents a bonding position, and preferably represents a bonding position with a hydrocarbon group.
The anion having a group represented by the formula (An-3) is preferably an anion represented by the following formula (An-3-1) or an anion represented by the following formula (An-3-2). .

In formula (An-3-1), R ^N1 to R ^N4 each independently represent a hydrogen atom or a substituent. Preferred examples of the substituent include an alkyl group, a cycloalkyl group, an alkoxy group, and a hydroxy group. R ^N1 to R ^N4 are preferably hydrogen atoms.
In formula (An-3-2), R ^N5 represents a substituent. V1 represents an integer from 0 to 4. Preferred examples of the substituent represented by R ^N5 include an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, and a hydroxy group. V1 is preferably 0 or 1, and more preferably 0.

* in formula (An-4) each represents a bonding position, and preferably represents a bonding position with a hydrocarbon group.

* in formula (An-5) represents a bonding position, and preferably represents a bonding position with a hydrocarbon group.
R ^A1 in formula (An-5) represents a hydrogen atom or a monovalent organic group. The monovalent organic group represented by R ^A1 is preferably an alkyl group, a cycloalkyl group, or an aryl group.
The alkyl group represented by R ^A1 may be linear or branched. The alkyl represented by R ^A1 preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms. The alkyl group may have a substituent, and the substituent is not particularly limited, but preferably, for example, a cycloalkyl group, a fluorine atom, or a cyano group. Examples of the cycloalkyl group as the above-mentioned substituent include the cycloalkyl group described below in the case where R ^A1 is a cycloalkyl group. Further, in the alkyl group represented by R ^A1 , one or more -CH ₂ - may be substituted with a carbonyl group.
The cycloalkyl group represented by R ^A1 may be monocyclic or polycyclic. The number of carbon atoms in the cycloalkyl group represented by R ^A1 is preferably 3 to 20, more preferably 5 to 12. Examples of the cycloalkyl group represented by R ^A1 include a norbornyl group and an adamantyl group. The cycloalkyl group represented by R ^A1 may have a substituent, and the substituent is not particularly limited, but an alkyl group (which may be linear or branched, preferably having 1 to 5 carbon atoms) is preferred. One or more of the carbon atoms that are ring member atoms of the cycloalkyl group represented by R ^A1 may be replaced with a carbonyl carbon atom.
The aryl group represented by R ^A1 may be monocyclic or polycyclic. The number of carbon atoms in the aryl group represented by R ^A1 is preferably 6 to 20, more preferably 6 to 12. Examples of the aryl group represented by R ^A1 include a phenyl group and a naphthyl group. The aryl group represented by R ^A1 may have a substituent, and the substituent is not particularly limited, but an alkyl group, a fluorine atom, or a cyano group is preferable. Examples of the alkyl group as the above-mentioned substituent include the alkyl group described above in the case where R ^A1 represents an alkyl group.
In R ^A1 in formula (An-5), the group directly bonding to N ^- is preferably neither -CO- nor -SO ₂ -.

The onium salt (A) is preferably a compound with an onium salt structure (photodegradable onium salt compound) that generates an acid upon irradiation with actinic rays or radiation. When the onium salt (A) is a photodegradable onium salt compound, the onium salt (A) itself is decomposed by exposure and the decomposition efficiency is high, so it is thought that the above-mentioned effect of improving dissolution contrast becomes even higher.

The photodegradable onium salt compound will be explained below.
A photodegradable onium salt compound is a compound that has at least one salt structure site consisting of an anion site and a cation site, and that decomposes upon exposure to light and generates an acid (preferably an organic acid). preferable.
The above-mentioned salt structure moiety of the photodegradable onium salt compound is composed of an organic cation moiety and an organic anion moiety with extremely low nucleophilicity because it is easily decomposed by exposure to light and is superior in producing organic acids. is preferred.
The above-mentioned salt structure site may be a part of the photodegradable onium salt compound, or may be the entirety. In addition, the case where the above-mentioned salt structure part is a part of a photodegradable onium salt compound corresponds to a structure in which two or more salt structure parts are connected, for example, as in the photodegradable onium salt PG2 described below. do.
The number of salt structural moieties in the photodegradable onium salt is not particularly limited, but is preferably from 1 to 10, preferably from 1 to 6, and more preferably from 1 to 3.

In the photodegradable onium salt compound, the cation moiety constituting the salt structure moiety is preferably an organic cation moiety, and in particular, an organic cation (cation (ZaI)) represented by the formula (ZaI) described below. Alternatively, an organic cation (cation (ZaII)) represented by the formula (ZaII) is preferable.

(Photodegradable onium salt compound PG1)
An example of a preferred embodiment of ^the photodegradable onium salt compound is an onium salt compound represented by "M ⁺ ).
In the compound represented by “M ⁺ X ⁻ ”, M ⁺ represents an organic cation, and X ⁻ represents an anion having a pKa of 2 or more of the aforementioned conjugate acid.
The photodegradable onium salt compound PG1 will be explained below.

The organic cation represented by M ⁺ in the photodegradable onium salt compound PG1 is an organic cation represented by the formula (ZaI) (cation (ZaI)) or an organic cation (cation (ZaI)) represented by the formula (ZaII). ZaII)) is preferred.

In the above formula (ZaI),
R ²⁰¹ , R ²⁰² and R ²⁰³ each independently represent an organic group.
The number of carbon atoms in the organic groups as R ²⁰¹ , R ²⁰² and R ²⁰³ is usually 1 to 30, preferably 1 to 20. Furthermore, two of R ²⁰¹ to R ²⁰³ may be combined to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester group, an amide group, or a carbonyl group. Examples of the group formed by combining two of R ²⁰¹ to R ²⁰³ include an alkylene group (for example, a butylene group and a pentylene group), and -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -. Can be mentioned.

Preferred embodiments of the organic cation in formula (ZaI) include cation (ZaI-1), cation (ZaI-2), and organic cation (cation (ZaI-3b)) represented by formula (ZaI-3b), which will be described later. ), and an organic cation (cation (ZaI-4b)) represented by the formula (ZaI-4b).

First, the cation (ZaI-1) will be explained.
The cation (ZaI-1) is an arylsulfonium cation in which at least one of R ²⁰¹ to R ²⁰³ in the above formula (ZaI) is an aryl group.
In the arylsulfonium cation, all of R ₂₀₁ to R ₂₀₃ may be an aryl group, or some of R ₂₀₁ to R ₂₀₃ may be an aryl group, and the remainder may be an alkyl group or a cycloalkyl group.
Further, one of R ₂₀₁ to R ₂₀₃ may be an aryl group, and the remaining two of R ²⁰¹ to R ²⁰³ may be bonded to form a ring structure, with an oxygen atom, a sulfur atom, It may contain an ester group, an amide group, or a carbonyl group. The group formed by combining two of R ²⁰¹ to R ²⁰³ includes, for example, one or more methylene groups substituted with an oxygen atom, a sulfur atom, an ester group, an amide group, and/or a carbonyl group. and alkylene groups (eg, butylene group, pentylene group, or -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -).
Examples of the arylsulfonium cation include triarylsulfonium cation, diarylalkylsulfonium cation, aryldialkylsulfonium cation, diarylcycloalkylsulfonium cation, and aryldicycloalkylsulfonium cation.

The aryl group contained in the arylsulfonium cation is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the heterocyclic structure include pyrrole residue, furan residue, thiophene residue, indole residue, benzofuran residue, and benzothiophene residue. When the arylsulfonium cation has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group or cycloalkyl group that the arylsulfonium cation has as necessary is a linear alkyl group having 1 to 15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, or a branched alkyl group having 3 to 15 carbon atoms. A cycloalkyl group is preferred, and for example, a methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, t-butyl group, cyclopropyl group, cyclobutyl group, and cyclohexyl group are more preferred.

The substituents that the aryl group, alkyl group, and cycloalkyl group of R ²⁰¹ to R ²⁰³ may each independently include an alkyl group (for example, carbon number 1 to 15), a cycloalkyl group (for example, carbon number 3-15), aryl group (e.g. carbon number 6-14), alkoxy group (e.g. carbon number 1-15), cycloalkylalkoxy group (e.g. carbon number 1-15), halogen atom (e.g. fluorine, iodine), hydroxy A carboxyl group, an ester group, a sulfinyl group, a sulfonyl group, an alkylthio group, a phenylthio group, and the like are preferred.
The above substituent may further have a substituent if possible. For example, the above alkyl group may have a halogen atom as a substituent to become a halogenated alkyl group such as a trifluoromethyl group. preferable.

Next, the cation (ZaI-2) will be explained.
The cation (ZaI-2) is a cation in which R ²⁰¹ to R ²⁰³ in the formula (ZaI) each independently represent an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group having no aromatic ring as R ²⁰¹ to R ²⁰³ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R ²⁰¹ to R ²⁰³ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, and a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxy A carbonylmethyl group is more preferred, and a linear or branched 2-oxoalkyl group is even more preferred.

The alkyl group and cycloalkyl group of R ²⁰¹ to R ²⁰³ include, for example, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group). group, butyl group, and pentyl group), and cycloalkyl groups having 3 to 10 carbon atoms (eg, cyclopentyl group, cyclohexyl group, and norbornyl group).
R ²⁰¹ to R ²⁰³ may be further substituted with a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxy group, a cyano group, or a nitro group.

Next, the cation (ZaI-3b) will be explained.
The cation (ZaI-3b) is a cation represented by the following formula (ZaI-3b).

In formula (ZaI-3b),
R _1c to R _5c each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, and a hydroxyl group. group, nitro group, alkylthio group, or arylthio group.
R _6c and R _7c each independently represent a hydrogen atom, an alkyl group (such as a t-butyl group), a cycloalkyl group, a halogen atom, a cyano group, or an aryl group.
R _x and R _y each independently represent an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group.

Any two or more of R _1c to R _5c , R _5c and R _6c , R _6c and R _7c , R _5c and R _x , and R _x and R _y may be bonded to each other to form a ring. Often, the rings may each independently contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond.
Examples of the above-mentioned ring include an aromatic or non-aromatic hydrocarbon ring, an aromatic or non-aromatic heterocycle, and a polycyclic condensed ring formed by combining two or more of these rings. Examples of the ring include a 3- to 10-membered ring, preferably a 4- to 8-membered ring, and more preferably a 5- or 6-membered ring.

Examples of the group formed by combining any two or more of R _1c to R _5c , R _6c and R _7c , and R _x and R _y include alkylene groups such as a butylene group and a pentylene group. The methylene group in this alkylene group may be substituted with a hetero atom such as an oxygen atom.
The group formed by bonding R _5c and R _6c and R _5c and R _x is preferably a single bond or an alkylene group. Examples of the alkylene group include a methylene group and an ethylene group.

R _1c to R _5c , R _6c , R _7c , R _x , R _y , and any two or more of R _1c to R 5c , R _5c and R _6c , R _6c and R _7c , _{R 5c} _and R _x , and the ring formed by bonding R _x and R _y to each other may have a substituent.

Next, the cation (ZaI-4b) will be explained.
The cation (ZaI-4b) is a cation represented by the following formula (ZaI-4b).

In formula (ZaI-4b),
l represents an integer from 0 to 2.
r represents an integer from 0 to 8.
_R13 is a group having a hydrogen atom, a halogen atom (e.g., a fluorine atom, an iodine atom, etc.), a hydroxy group, an alkyl group, a halogenated alkyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or a cycloalkyl group (a cycloalkyl group). It may be an alkyl group itself or a group partially containing a cycloalkyl group). These groups may have substituents.
_R14 is a hydroxy group, a halogen atom (for example, a fluorine atom, an iodine atom, etc.), an alkyl group, a halogenated alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a cyclo Represents a group having an alkyl group (which may be a cycloalkyl group itself or a group partially containing a cycloalkyl group). These groups may have substituents. When a plurality of R _14s exist, each independently represents the above group such as a hydroxy group.
R ₁₅ each independently represents an alkyl group, a cycloalkyl group, or a naphthyl group. Two R _15s may be bonded to each other to form a ring. When two R _15s combine with each other to form a ring, the ring skeleton may contain a heteroatom such as an oxygen atom or a nitrogen atom. In one embodiment, two R _15s are alkylene groups and are preferably bonded to each other to form a ring structure. The ring formed by bonding the alkyl group, cycloalkyl group, naphthyl group, and two R _15s to each other may have a substituent.

In formula (ZaI-4b), the alkyl groups of R ₁₃ , R ₁₄ and R ₁₅ are preferably linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 10. As the alkyl group, a methyl group, ethyl group, n-butyl group, or t-butyl group is more preferable.

Next, formula (ZaII) will be explained.
In formula (ZaII), R ²⁰⁴ and R ²⁰⁵ each independently represent an aryl group, an alkyl group, or a cycloalkyl group.
The aryl group for R ²⁰⁴ and R ²⁰⁵ is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group of R ²⁰⁴ and R ²⁰⁵ may be an aryl group having a heterocycle having an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the skeleton of the aryl group having a heterocycle include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene.
The alkyl group and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ include a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, butyl group, pentyl group), or a cycloalkyl group having 3 to 10 carbon atoms (eg, cyclopentyl group, cyclohexyl group, or norbornyl group).

The aryl group, alkyl group, and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ may each independently have a substituent. Examples of substituents that the aryl group, alkyl group, and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ may have include an alkyl group (for example, having 1 to 15 carbon atoms), a cycloalkyl group (for example, having 3 to 15 carbon atoms), 15), an aryl group (for example, having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxy group, and a phenylthio group.

The molecular weight of the photodegradable onium salt compound PG1 is preferably 3000 or less, more preferably 2000 or less, and even more preferably 1000 or less.

(Photodegradable onium salt compound PG2)
In addition, as another example of a preferred embodiment of the photodegradable onium salt compound, the following compound (I) and compound (II) (hereinafter, "compound (I) and compound (II)") are referred to as "photodegradable onium salt compound PG2". ). The photodegradable onium salt compound PG2 is a compound that has two or more of the above-described salt structure sites and generates a polyvalent organic acid upon exposure to light.
The photodegradable onium salt compound PG2 will be explained below.

《Compound (I)》
Compound (I) is a compound having one or more of the following structural moieties X and one or more of the following structural moieties Y, and the following first acidic acid derived from the following structural moiety This is a compound that generates an acid containing the following second acidic site derived from the structural site Y below.
^structural _site _{_} ^_ _{_} ₂ ^- and a cationic site M ₂ ⁺ , and forms a second acidic site represented by HA ₂ upon irradiation with actinic rays or radiation. However, compound (I) satisfies the following condition I.

Condition I: A compound PI obtained by replacing the cation moiety M ₁ ⁺ in the structural moiety X and the cation moiety M ₂ ⁺ in the structural moiety Y with H ⁺ in the compound (I) is The acid dissociation constant a1 (pKa ₁ ) derived from the acidic site represented by HA ₁ obtained by replacing the cationic site M ₁ ⁺ with H ⁺ and the cationic site M ₂ ⁺ in the structural site Y with H ⁺ It has an acid dissociation constant a2 (pKa ₂ ) derived from the acidic site represented by HA ₂ , and the acid dissociation constant a2 is larger than the acid dissociation constant a1. However, pKa ₁ and pKa ₂ are 2 or more.
The above-mentioned compound PI corresponds to an acid generated when compound (I) is irradiated with actinic rays or radiation.

When compound (I) has two or more structural sites X, the structural sites X may be the same or different. Furthermore, the two or more A ₁ ⁻ and the two or more M ₁ ⁺ may be the same or different.
Further, in compound (I), the above A ₁ ^- and the above A ₂ ^- , and the above M ₁ ⁺ and the above M ₂ ⁺ may be the same or different, but the above A ₁ ^- and the above Preferably, each A ₂ ^- is different.

The anion site A ₁ ^- and the anion site A ₂ ^- are structural sites containing a negatively charged atom or atomic group, and are a group represented by the above formula (An-1), a group represented by the formula (An-2), At least one selected from the group consisting of a group represented by the formula (An-3), a group represented by the formula (An-4), and a group represented by the formula (An-5). It is preferable that there be.

Further, the cationic site M ₁ ⁺ and the cationic site M ₂ ⁺ are structural sites containing positively charged atoms or atomic groups, such as monovalent organic cations. The organic cation is not particularly limited, but is preferably an organic cation (cation (ZaI)) represented by the above-mentioned formula (ZaI) or an organic cation (cation (ZaII)) represented by the formula (ZaII).

《Compound (II)》
Compound (II) is a compound having two or more of the above structural moieties It is a compound that generates an acid containing two or more sites and the above structural site Z.
Structural site Z: nonionic site capable of neutralizing acids

The above compound (II) is a compound PII (acid) having an acidic site represented by HA ₁ obtained by replacing the above cation site M ₁ ⁺ in the above structural site X with H ⁺ by irradiation with actinic rays or radiation. It can occur. That is, compound PII represents a compound having the acidic site represented by HA ₁ above and the structural site Z, which is a nonionic site capable of neutralizing acid.
In addition, the definition of the structural moiety X and the definitions of A ₁ ^- and M ₁ ⁺ in compound (II) are the same as the definition of the structural moiety X and A ₁ ^- and M ₁ ⁺ in compound (I) described above. It has the same meaning as the definition, and the preferred embodiments are also the same.
Furthermore, the two or more structural sites X may be the same or different. Furthermore, the two or more A ₁ ⁻ and the two or more M ₁ ⁺ may be the same or different.

The nonionic site that can neutralize the acid in the structural site Z is not particularly limited, and is preferably a site that contains a group that can electrostatically interact with protons or a functional group that has electrons. .
As a group capable of electrostatic interaction with protons or a functional group having electrons, a functional group having a macrocyclic structure such as a cyclic polyether, or a nitrogen atom having a lone pair of electrons that does not contribute to π conjugation is used. Examples include functional groups having such a functional group. A nitrogen atom having a lone pair of electrons that does not contribute to π conjugation is, for example, a nitrogen atom having a partial structure shown in the following formula.

Examples of partial structures of functional groups having groups or electrons that can electrostatically interact with protons include crown ether structures, aza crown ether structures, primary to tertiary amine structures, pyridine structures, imidazole structures, and pyrazine structures. Among them, primary to tertiary amine structures are preferred.

The molecular weight of the photodegradable onium salt compound PG2 is preferably 100 to 10,000, more preferably 100 to 2,500, even more preferably 100 to 1,500.

Specific examples of the anion contained in the onium salt (A) are shown below, but the anion is not limited thereto. Note that Aa6 to Aa9 contain at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.

The pKa of the conjugate acid of each of the above anions is shown in Table 1 below.

Specific examples of the cation contained in the onium salt (A) are shown below, but the cation is not limited thereto. Note that Ac2 includes at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.

Specific examples (A-1 to A-27) of the onium salt (A) are shown in Table 2 below according to the combinations of anions and cations contained in each compound, but the onium salt (A) is not limited to these.

The content of the onium salt (A) in the resist composition of the present invention is not particularly limited, but is preferably 0.5% by mass or more, more preferably 1.0% by mass or more based on the total solid content of the resist composition. It is preferably 5.0% by mass or more, and more preferably 5.0% by mass or more. Further, the content is preferably 40.0% by mass or less, more preferably 30.0% by mass or less.
Onium salts (A) may be used alone or in combination of two or more. When two or more types are used, it is preferable that the total content is within the above-mentioned preferred content range.

<Polymer (B)>
The resist composition of the present invention contains a repeating unit having an interactive group that interacts with the onium salt (A), and is a polymer ("polymer (B)") whose main chain is decomposed by irradiation with actinic rays or radiation. (also called).
The polymer (B) is a different compound from the onium salt (A). Therefore, a polymer that corresponds to an onium salt containing an anion whose conjugate acid has a pKa of 2 or more does not correspond to the polymer (B).
The polymer (B) is a so-called main chain-cleaved polymer whose main chain is decomposed (the main chain is cut) by irradiation with actinic rays or radiation. The polymer (B) is preferably a polymer whose main chain decomposes when irradiated with X-rays, electron beams or extreme ultraviolet rays, and preferably whose main chain decomposes when irradiated with electron beams or extreme ultraviolet rays. More preferred.
The polymer (B) may be a homopolymer or a copolymer.

The polymer (B) contains repeating units having an interactive group that interacts with the onium salt (A).
The interactive group that interacts with the onium salt (A) is preferably at least one selected from the group consisting of a hydroxy group, a carboxy group, an imide group, a sulfonimide group, and a thiol group. The imide group is preferably a group represented by the following formula (M1). The sulfonimide group is preferably a group represented by the following formula (M2) or (M3).

In formulas (M1) to (M3), R ^M1 to R ^M4 each independently represent a hydrogen atom or a substituent. * each represents a substitution position.
The substituents represented by R ^M1 to R ^M4 are preferably organic groups, and examples of the organic group include groups exemplified as the organic group W described below. In R ^M3 and R ^M4 in formula (M3), the group directly bonding to the nitrogen atom is preferably neither -CO- nor -SO ₂ -.

It is preferable that the polymer (B) contains a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2).

In formula (1), X represents a halogen atom. R ⁰ and A ¹ each independently represent a hydrogen atom or an organic group. L ¹ represents -O- or -NR ¹ -. R ¹ represents a hydrogen atom or an organic group. R ⁰ and A ¹ or R ¹ may be bonded to each other to form a ring.
In formula (2), Y represents a hydrogen atom or a hydrocarbon group. A ² represents an organic group.
However, at least one of A ¹ and A ² has an interactive group that interacts with the onium salt (A).

The interactive group that interacts with the onium salt (A), which at least one of A ¹ and A ² has, is at least one selected from the group consisting of a hydroxy group, a carboxy group, an imide group, a sulfonimide group, and a thiol group. It is preferable that
It is preferred that at least A ¹ has an interactive group that interacts with the onium salt (A).

(Repeating unit represented by formula (1))
The repeating unit represented by formula (1) will be explained.
Since the polymer (B) contains the repeating unit represented by formula (1), the main chain is easily decomposed by irradiation with actinic rays or radiation.
Examples of the halogen atom represented by X include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like. The halogen atom represented by X is preferably a chlorine atom, a bromine atom, or an iodine atom, and more preferably a chlorine atom, since the effects of the present invention are more excellent.

R ⁰ , R ¹ and A ¹ each independently represent a hydrogen atom or an organic group. The organic groups represented by R ⁰ , R ¹ and A ¹ are not particularly limited, and include, for example, groups exemplified as the organic group W below.

(Organic group W)
The organic group W is, for example, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a cycloalkynyl group, an aryl group, a heteroaryl group, an aralkyl group, a cyano group, an alkoxy group, an aryloxy group, a heterocycle. Oxy group, acyl group (alkylcarbonyl group or arylcarbonyl group), acyloxy group (alkylcarbonyloxy group or arylcarbonyloxy group), carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, alkylthio group, arylthio group, Heterocyclic thio group, alkyl or arylsulfinyl group, alkyl or arylsulfonyl group, aryloxycarbonyl group, alkoxycarbonyl group, aryl or heterocyclic azo group, sulfonamide group, imide group, acylamino group, carbamoyl group, lactone group, etc. Can be mentioned.
Moreover, each of the above-mentioned groups may further have a substituent, if possible. For example, an alkyl group which may have a substituent is also included as one form of the organic group W. The above substituents are not particularly limited, but include, for example, one or more of the groups shown as the organic group W above, a halogen atom, a nitro group, a primary to tertiary amino group, a phosphino group, a phosphinyl group, Examples include a phosphinyloxy group, a phosphinylamino group, a phosphono group, a silyl group, a hydroxy group, a carboxy group, a sulfonic acid group, a phosphoric acid group (hereinafter, these are referred to as "substituent T").
Further, the number of carbon atoms in the organic group W is, for example, 1 to 20.
Further, the number of atoms other than hydrogen atoms that the organic group W has is, for example, 1 to 30.

Further, the number of carbon atoms in the alkyl group exemplified in the organic group W is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6.
The alkyl group may be either linear or branched.
Examples of the alkyl group include linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, t-butyl group, and n-hexyl group. It will be done.
In the alkyl group which may have a substituent, the substituent which the alkyl group may have is not particularly limited, and includes, for example, the groups exemplified by the above-mentioned substituent T.

The alkyl group moiety in the alkoxy group (including the alkoxy group moiety in a substituent containing an alkoxy group (e.g., alkoxycarbonyloxy group)), the alkyl group moiety in an aralkyl group, and the alkyl group in an alkylcarbonyl group exemplified in the organic group W As the alkyl group moiety in the alkylcarbonyloxy group, the alkyl group moiety in the alkylthio group, the alkyl group moiety in the alkylsulfinyl group, and the alkyl moiety in the alkylsulfonyl group, the above alkyl groups are preferable. Also, an alkoxy group that may have a substituent, an aralkyl group that may have a substituent, an alkylcarbonyloxy group that may have a substituent, an alkylthio group that may have a substituent, a substituent In the alkylsulfinyl group which may have a substituent, and the alkylsulfonyl group which may have a substituent, an alkoxy group, an aralkyl group, an alkylcarbonyloxy group, an alkylthio group, an alkylsulfinyl group, and an alkylsulfonyl group have Examples of the substituent which may be substituted include the same substituents as those for the alkyl group which may have a substituent.

Examples of the cycloalkyl group for the organic group W include monocyclic cycloalkyl groups such as cyclopentyl group and cyclohexyl group, polycyclic cycloalkyl groups such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group, and adamantyl group. Examples include alkyl groups. The number of carbon atoms in the cycloalkyl group is preferably 5 to 20, more preferably 5 to 15. In the cycloalkyl group which may have a substituent, examples of the substituent which the cycloalkyl group may have are the same as those for the alkyl group which may have a substituent.
The alkenyl group exemplified in the organic group W may be either linear or branched. The alkenyl group preferably has 2 to 20 carbon atoms. In the alkenyl group which may have a substituent, examples of the substituent which the alkenyl group may have are the same as those for the alkyl group which may have a substituent.
The cycloalkenyl group exemplified in the organic group W preferably has 5 to 20 carbon atoms. In the cycloalkenyl group which may have a substituent, examples of the substituent which the cycloalkenyl group may have are the same as those for the alkyl group which may have a substituent.
The alkynyl group exemplified in the organic group W may be either linear or branched. The number of carbon atoms in the alkynyl group is preferably 2 to 20. In the alkynyl group which may have a substituent, examples of the substituent which the alkynyl group may have are the same as those for the alkyl group which may have a substituent.
The cycloalkynyl group exemplified as the organic group W preferably has 5 to 20 carbon atoms. In the cycloalkynyl group which may have a substituent, examples of the substituent which the cycloalkynyl group may have are the same as those for the alkyl group which may have a substituent.

The aryl group exemplified in the organic group W may be either monocyclic or polycyclic (eg, 2-6 rings, etc.) unless otherwise specified.
The number of ring member atoms in the aryl group is preferably 6 to 15, more preferably 6 to 10.
The aryl group is preferably a phenyl group, a naphthyl group, or an anthranyl group, and more preferably a phenyl group.
In the aryl group which may have a substituent, examples of the substituent which the aryl group may have are the same as those for the alkyl group which may have a substituent.
Furthermore, among the groups exemplified in the organic group W, the same examples as the aryl group exemplified in the above organic group W are given for the aryl group moiety in a substituent containing an aryl group (for example, an aryloxy group). It will be done.

The heteroaryl group exemplified in the organic group W may be either monocyclic or polycyclic (eg, 2-6 rings, etc.) unless otherwise specified.
The number of heteroatoms that the heteroaryl group has as ring member atoms is, for example, 1 to 10. Examples of the heteroatoms include nitrogen atom, sulfur atom, oxygen atom, selenium atom, tellurium atom, phosphorus atom, silicon atom, and boron atom.
The number of ring member atoms in the heteroaryl group is preferably 5 to 15.
In the heteroaryl group which may have a substituent, examples of the substituent which the heteroaryl group may have are the same as those for the alkyl group which may have a substituent.

The heterocycle exemplified in the organic group W is intended to be a ring containing a hetero atom as a ring member atom, and unless otherwise specified, it may be either an aromatic heterocycle or an aliphatic heterocycle, and may include a monocyclic ring and a polycyclic ring. It may be any ring (for example, 2 to 6 rings, etc.).
The number of heteroatoms that the heterocycle has as ring member atoms is, for example, 1 to 10. Examples of the heteroatoms include nitrogen atom, sulfur atom, oxygen atom, selenium atom, tellurium atom, phosphorus atom, silicon atom, and boron atom.
The number of ring member atoms in the heterocycle is preferably 5 to 15.
In the heterocycle which may have a substituent, examples of the substituent which the heterocycle may have are similar to the substituents in the alkyl group which may have a substituent.

The lactone group exemplified in the organic group W is preferably a 5- to 7-membered lactone group, and another ring structure is fused to the 5- to 7-membered lactone ring to form a bicyclo structure or a spiro structure. It is more preferable that
In the lactone group that may have a substituent, examples of the substituent that the lactone group may have include the same as the substituents for the alkyl group that may have a substituent.

Hydrogen atoms are preferred as R ⁰ and R ¹ .
A ¹ preferably represents an organic group.

R ⁰ and A ¹ or R ¹ may be bonded to each other to form a ring.
The ring formed by R ⁰ bonding with A ¹ or R ¹ is not particularly limited, and may be either monocyclic or polycyclic. The above-mentioned ring may contain heteroatoms such as oxygen atom, nitrogen atom, and sulfur atom, and/or carbonyl carbon as ring member atoms.
Preferably, the ring is a 5- or 6-membered alicyclic ring.

Hereinafter, specific examples of monomers corresponding to the repeating units represented by formula (1) (monomers that provide repeating units represented by formula (1) by polymerization) will be given, but the monomers are not limited to these. Note that 1-d, 1-f, 1-h, and 1-m to 1-o have an interactive group that interacts with the onium salt (A).

In the polymer (B), the content of the repeating unit represented by formula (1) is preferably 20 mol% or more, more preferably 30 mol% or more, based on all repeating units. More preferably, it is 40 mol% or more. Further, the content of the repeating unit represented by formula (1) is preferably 80 mol% or less, more preferably 70 mol% or less, and 60 mol% or less based on the total repeating units. It is even more preferable that there be one.
In the polymer (B), one type of repeating unit represented by formula (1) may be contained alone, or two or more types may be contained. When two or more types are included, the total content is preferably within the above-mentioned preferred content range.

(Repeating unit represented by formula (2))
The repeating unit represented by formula (2) will be explained.
Y represents a hydrogen atom or a hydrocarbon group, preferably a hydrocarbon group.
Examples of the hydrocarbon group represented by Y include linear or branched alkyl groups, cycloalkyl groups, and aryl groups.
The alkyl group represented by Y is preferably an alkyl group exemplified as the organic group W, more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group or an ethyl group.
The cycloalkyl group represented by Y is preferably the cycloalkyl group exemplified as the organic group W, and more preferably a cyclohexyl group.
The aryl group represented by Y is preferably the aryl group exemplified as the organic group W, and more preferably a phenyl group or a naphthyl group.

The organic group represented by A ² is not particularly limited, but for example, -CH ₂ - is substituted with one or more groups selected from the group consisting of -O-, -CO-, and -NR ^T -. It is preferable to represent a hydrocarbon group which may have a substituent.
The above R ^T represents a hydrogen atom or an organic group.

Examples of the above-mentioned hydrocarbon group that may have a substituent include an alkyl group that may have a substituent (which may be linear or branched); Examples thereof include a cycloalkyl group and an aryl group (either monocyclic or polycyclic) which may have a substituent.
The alkyl group which may have a substituent is preferably the alkyl group exemplified as the organic group W, more preferably an alkyl group having 1 to 6 carbon atoms which may have a substituent. Examples of the substituent that the alkyl group may have include the same substituents as the alkyl group that may have a substituent described above as the organic group W.
The cycloalkyl group which may have a substituent is preferably a cycloalkyl group exemplified as the organic group W, and more preferably a cyclohexyl group which may have a substituent. Examples of the substituent that the cycloalkyl group may have include the same examples as the substituents for the alkyl group that may have a substituent described above as the organic group W.
The aryl group which may have a substituent is preferably an aryl group exemplified as the organic group W, and more preferably a phenyl group which may have a substituent. Examples of the substituent that the aryl group may have include the same substituents as the alkyl group that may have a substituent described above as the organic group W.
Further, the organic group represented by ^RT is not particularly limited, and includes, for example, the organic group W described in the upper part.

-CH ₂ - represented by A ² has a substituent, which may be substituted with one or more groups selected from the group consisting of -O-, -CO-, and -NR ^T - Examples of the hydrocarbon group that may have a substituent include, but are not particularly limited to, hydrocarbon groups that may have a substituent, -O-L ² -R ^a , -NR ^b R ^c , and -CO-L ³ - Examples include R ^d and the like.
R ^a to R ^d each independently represent a hydrocarbon group. The above hydrocarbon group may have a substituent. R ^b and R ^c may be combined with each other to form a ring. The above L ² represents a single bond or -CO-. The above L ³ represents -O- or -NR ^e -. R ^e represents a hydrogen atom or an organic group.
Further, the ring formed by bonding R ^b and R ^c to each other is not particularly limited, and may be either a monocyclic ring or a polycyclic ring. The ring may contain at least one of a heteroatom and carbonyl carbon as a ring member atom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, and the like. Preferably, the ring is a 5- or 6-membered alicyclic ring.
The organic group represented by ^Re is not particularly limited, and includes, for example, the organic group W described above.

The repeating unit represented by formula (2) is selected from the repeating unit represented by the following formula (2)-1 to the repeating unit represented by the following formula (2)-4 in that the effect of the present invention is more excellent. The repeating unit is preferably at least one selected from the group consisting of: more preferably a repeating unit represented by formula (2)-1.

In formula (2)-1, Y represents a hydrogen atom or a hydrocarbon group. Ar represents an aryl group.
In formula (2)-2, Y represents a hydrogen atom or a hydrocarbon group. L ² represents a single bond or -CO-. R ^a represents a hydrocarbon group.
In formula (2)-3, Y represents a hydrogen atom or a hydrocarbon group. R ^b and R ^c each independently represent a hydrocarbon group. R ^b and R ^c may be combined with each other to form a ring.
In formula (2)-4, Y represents a hydrogen atom or a hydrocarbon group. L ³ represents -O- or -NR ^e -. R ^e represents a hydrogen atom or an organic group. R ^d represents a hydrocarbon group.

Y in formulas (2)-1 to (2)-4 has the same meaning as Y in formula (2), and preferred embodiments are also the same.

In formula (2)-1, Ar represents an aryl group, and the aryl group may have a substituent.
The aryl group represented by Ar is preferably an aryl group exemplified as the organic group W described above, and more preferably a phenyl group which may have a substituent. Examples of the substituent that the aryl group may have include the same substituents as the alkyl group that may have a substituent described above as the organic group W.

R ^a , R ^b , R ^c and R ^d in formulas (2)-2 to (2)-4 each independently represent a hydrocarbon group. The above hydrocarbon group may have a substituent.
The hydrocarbon groups that may have substituents represented by R ^a , R ^b , R ^c and R ^d include alkyl groups that may have substituents (both linear and branched). ), a cycloalkyl group which may have a substituent, and an aryl group (which may be monocyclic or polycyclic) which may have a substituent.
The alkyl group which may have a substituent is preferably the alkyl group exemplified as the organic group W, more preferably an alkyl group having 1 to 6 carbon atoms which may have a substituent. Examples of the substituent that the alkyl group may have include the same substituents as the alkyl group that may have a substituent described above as the organic group W.
The cycloalkyl group which may have a substituent is preferably a cycloalkyl group exemplified as the organic group W, and more preferably a cyclohexyl group which may have a substituent. Examples of the substituent that the cycloalkyl group may have include the same examples as the substituents for the alkyl group that may have a substituent described above as the organic group W.
The aryl group which may have a substituent is preferably an aryl group exemplified as the organic group W, and more preferably a phenyl group which may have a substituent. Examples of the substituent that the aryl group may have include the same substituents as the alkyl group that may have a substituent described above as the organic group W.

Furthermore, R ^b and R ^c may be combined with each other to form a ring. The ring formed by combining R ^b and R ^c with each other is not particularly limited, and may be either a monocyclic ring or a polycyclic ring. The ring may contain at least one of a heteroatom and carbonyl carbon as a ring member atom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, and the like. Preferably, the ring is a 5- or 6-membered alicyclic ring.

In formula (2)-4, L ³ represents -O- or -NR ^e -. R ^e represents a hydrogen atom or an organic group.
The organic group represented by ^Re is not particularly limited, and includes, for example, the organic group W described above.

The repeating unit represented by formula (2) is a repeating unit derived from a monomer selected from the group consisting of α-methylstyrenes, isopropenyl ethers, isopropenylamines, and methacrylic acid esters. is also preferable.

Hereinafter, specific examples of monomers corresponding to the repeating units represented by formula (2) (monomers that provide repeating units represented by formula (2) by polymerization) will be given, but the monomers are not limited to these. Note that 2-a to 2-s and 2-x have an interactive group that interacts with the onium salt (A). Furthermore, 2-b, 2-c, 2-f, 2-h, 2-m, 2-n, and 2-n7 are at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group. Contains one.

In the polymer (B), the content of the repeating unit represented by formula (2) is preferably 20 mol% or more, more preferably 30 mol% or more, based on all repeating units. More preferably, it is 40 mol% or more. Further, the content of the repeating unit represented by formula (2) is preferably 80 mol% or less, more preferably 70 mol% or less, and 60 mol% or less based on the total repeating units. It is even more preferable that there be one.
In the polymer (B), one type of repeating unit represented by formula (2) may be contained alone, or two or more types may be contained. When two or more types are included, the total content is preferably within the above-mentioned preferred content range.

The polymer (B) preferably contains a repeating unit having an interactive group that interacts with the onium salt (A), and the repeating unit has two interacting groups that interact with the onium salt (A). It is more preferable to have one or more.
It is preferable that the polymer (B) contains a repeating unit represented by the following formula (3). The repeating unit represented by the following formula (3) is one of the preferred embodiments of the repeating unit represented by the above formula (2).

In formula (3), k represents an integer from 2 to 5. A ³ represents an interactive group that interacts with the onium salt (A). A plurality of ^A3s may be the same or different. L ⁴ represents a single bond or a connecting group. A plurality of L ⁴ may be the same or different. A plurality of L ⁴ may be bonded to each other to form a ring.

k represents an integer of 2 to 5, preferably an integer of 2 to 4, and more preferably 2 or 3.

The interactive group represented by A ³ that interacts with the onium salt (A) is preferably at least one selected from the group consisting of a hydroxy group, a carboxy group, an imide group, and a thiol group.

The linking group represented by L ⁴ is not particularly limited, but is preferably a divalent organic group, more preferably an alkylene group or an alkenylene group, and an alkylene group having 1 to 6 carbon atoms or an alkylene group having 2 to 6 carbon atoms. More preferably, it is an alkenylene group.

A plurality of L ⁴ may be bonded to each other to form a ring, and the ring is preferably an aromatic ring, and more preferably a benzene ring.

In the polymer (B), the content of the repeating unit represented by formula (3) is preferably 20 mol% or more, more preferably 30 mol% or more, based on all repeating units. More preferably, it is 40 mol% or more. Further, the content of the repeating unit represented by formula (3) is preferably 80 mol% or less, more preferably 70 mol% or less, and 60 mol% or less based on the total repeating units. It is even more preferable that there be one.
In the polymer (B), one type of repeating unit represented by formula (3) may be contained alone, or two or more types may be contained. When two or more types are included, the total content is preferably within the range of the above-mentioned preferred content.

It is preferable that the polymer (B) contains a repeating unit represented by the following formula (1)-1 and a repeating unit represented by the following formula (3)-1.

In formula (1)-1, X represents a halogen atom. R ^f represents a hydrogen atom or an organic group.
In formula (3)-1, Z ¹ represents a hydroxy group or a carboxy group.
Examples of the halogen atom represented by X include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like. The halogen atom represented by X is preferably a chlorine atom, a bromine atom, or an iodine atom, and more preferably a chlorine atom, since the effects of the present invention are more excellent.
Examples of the organic group represented by R ^f include the above-mentioned organic group W, and an alkyl group or an aralkyl group is preferable.

In the polymer (B), the content of the repeating unit represented by formula (1)-1 and the repeating unit represented by formula (3)-1 is 20 mol% or more, respectively, based on the total repeating units. The content is preferably 30 mol% or more, more preferably 40 mol% or more. Further, the content of the repeating unit represented by formula (1)-1 and the repeating unit represented by formula (3)-1 is preferably 80 mol% or less, respectively, based on the total repeating units. , more preferably 70 mol% or less, and even more preferably 60 mol% or less.
In the polymer (B), one type of repeating unit represented by formula (1)-1 may be contained alone, or two or more types may be contained. When two or more types are included, the total content is preferably within the above-mentioned preferred content range.

In the polymer (B), the total content of repeating units represented by the above formula (1) and repeating units represented by the above formula (2) is 90 mol% or more based on all repeating units. It is preferably present, and more preferably 95 mol% or more. In addition, as an upper limit, 100 mol% or less is preferable.

When the polymer (B) is a copolymer containing a repeating unit represented by the above formula (1) and a repeating unit represented by the above formula (2), it may be a random copolymer, a block copolymer or an alternating copolymer. It may be in any form of a copolymer (a copolymer in which repeating units represented by the above formula (1) and repeating units represented by the above formula (2) are arranged alternately), but Preferably, it is a copolymer.
A preferred embodiment of the polymer (B) is an embodiment in which the proportion of the alternating copolymer in the polymer (B) is 90% by mass or more (preferably 100% by mass or more, based on the total mass of the polymer (B)). % by mass).

The polymer (B) may contain repeating units other than the above-mentioned repeating units as long as the effects of the present invention are not impaired. The content of repeating units other than the above-mentioned repeating units is preferably 10% by mass or less, more preferably 5% by mass or less, and 0% by mass based on the total repeating units of the polymer (B). % is more preferable.

The lower limit of the weight average molecular weight of the polymer (B) is preferably 25,000 or more, and 30,000 or more is preferable in that it improves heat resistance, suppresses deterioration of dry etching resistance, and provides more excellent effects of the present invention. is more preferable, 35,000 or more is still more preferable, 40,000 or more is particularly preferable, and 50,000 or more is most preferable. In addition, the upper limit value is preferably 200,000 or less, more preferably 150,000 or less, from the viewpoints of better developability and better suppression of deterioration of film formability due to increase in viscosity. It is more preferably 100,000 or less, particularly preferably 85,000 or less. Note that the above weight average molecular weight value is a value determined as a polystyrene equivalent value by GPC method.
The degree of dispersion (molecular weight distribution) of the polymer (B) is usually 1.0 to 5.0, preferably 1.0 to 3.0, more preferably 1.2 to 3.0, and 1.2 ~2.5 is more preferred. When the degree of dispersion is within the above range, the resolution and resist shape tend to be better.

The polymer (B) can be synthesized according to conventional methods (eg, radical polymerization).

In the resist composition of the present invention, the content of the polymer (B) is preferably 50.0% by mass or more, more preferably 60.0% by mass or more, and 70.0% by mass or more, based on the total solid content of the resist composition. More preferably, it is 0% by mass or more. Further, the content of the polymer (B) is preferably 99.5% by mass or less, more preferably 99.0% by mass or less, and still more preferably 95.0% by mass or less based on the total solid content of the resist composition. preferable.
Only one type of polymer (B) may be used, or a plurality of them may be used in combination. When two or more types are used, it is preferable that the total content is within the range of the above-mentioned preferred content.

The onium salt (A) and the polymer (B) are different compounds. When the onium salt (A) and the polymer (B) are different compounds, it is easy to freely control the blending ratio of each, and the solubility in the developer can be increased, thereby improving developability. As a result, resolution and LWR performance are improved.

The resist composition of the present invention satisfies at least one of the following (1) to (3).
(1) The resist composition contains at least one selected from the group consisting of an antioxidant, a polymerization inhibitor, and a chain transfer agent.
(2) The above onium salt (A) contains at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.
(3) The polymer (B) contains at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.
By satisfying at least one of the conditions (1) to (3) above, the resist composition of the present invention can efficiently carry out the crosslinking reaction, which is a side reaction of the main chain decomposition reaction of the polymer (B) that occurs upon exposure. Since it is possible to suppress the dissolution contrast, it is considered that the dissolution contrast can be improved, and as a result, high resolution and high LWR performance can be exhibited.
Compounds included in the group consisting of antioxidants, polymerization inhibitors, and chain transfer agents are also referred to as "compounds (C)."
Groups included in the group consisting of antioxidant groups, polymerization termination groups, and chain transfer groups are also referred to as "specific groups (D)."

<Compound (C)>
A case where the resist composition of the present invention satisfies the above (1) (that is, a case where the resist composition contains at least one compound (C)) will be described.
The compound (C) is preferably a compound different from the onium salt (A) and the polymer (B).
As the compound (C), compounds known as antioxidants, polymerization inhibitors, or chain transfer agents can be used.
Compound (C) is preferably at least one selected from the group consisting of polyhydric phenol compounds, amine compounds, thiol compounds, phosphorus compounds, sugar compounds, nitro compounds, and nitroso compounds; More preferably, it is at least one selected from the group consisting of and nitroso compounds.

The polyhydric phenol compound is a compound in which one aromatic ring is substituted with two or more hydroxy groups, and more preferably a compound in which one aromatic hydrocarbon ring is substituted with two or more hydroxy groups. It is more preferable that the compound has six to twenty aromatic hydrocarbon rings substituted with two or more hydroxy groups, and it is particularly preferable that the compound has a benzene ring or naphthalene ring substituted with two or more hydroxy groups. Most preferred are compounds in which the benzene ring is substituted with two or more hydroxy groups. The number of hydroxy groups substituted on one aromatic ring of the polyhydric phenol compound is preferably 2 or more and 4 or less, more preferably 2 or 3.
As the amine compound, a hindered amine light stabilizer (HALS), an aromatic amine compound, or a metal salt of dithiocarbamic acid (for example, a zinc salt of dithiocarbamic acid) is preferable.
Examples of the amine compound include a compound represented by the following formula (CA-1), a compound represented by the following formula (CA-2), a compound represented by the following formula (CA-3), and a compound represented by the following formula (CA-4). ) is preferably at least one selected from the group consisting of compounds represented by.

In formula (CA-1), R ^C1 and R ^C2 each independently represent a hydrogen atom or a substituent.
In formula (CA-2), R ^C3 and R ^C4 each independently represent a hydrogen atom or a substituent. R ^C5 represents a substituent. c1 represents an integer from 0 to 4. When a plurality of R ^C5s exist, the plurality of R ^C5s may be the same or different. A plurality of R ^C5s may be bonded to each other to form a ring.
In formula (CA-3), R ^C6 and R ^C7 each independently represent a substituent. c2 and c3 each independently represent an integer from 0 to 5. When a plurality of R ^C6s exist, the plurality of R ^C6s may be the same or different. A plurality of R ^C6 may be bonded to each other to form a ring. When a plurality of R ^C7s exist, the plurality of R ^C7s may be the same or different. A plurality of R ^C7s may be bonded to each other to form a ring.
In formula (CA-4), R ^C8 and R ^C9 each independently represent a substituent. c4 and c5 each independently represent an integer of 0 to 4. When a plurality of R ^C8s exist, the plurality of R ^C8s may be the same or different. A plurality of R ^C8 may be bonded to each other to form a ring. When a plurality of R ^C9s exist, the plurality of R ^C9s may be the same or different. A plurality of R ^C9s may be bonded to each other to form a ring. L ^C1 represents a single bond or a divalent linking group.

The substituents represented by R ^C1 and R ^C3 are not particularly limited, but include, for example, an organic group, a hydroxy group, a halogen atom, an amino group (the amino group may have a substituent, and the substituents include the above-mentioned organic groups). and the like. Examples of the organic group include the organic group W described above.
The substituents represented by R ^C2 and R ^C4 are not particularly limited, but include, for example, an organic group, -O. (oxy radical group), and the like. Examples of the organic group include the organic group W described above.
The substituent represented by R ^C5 is not particularly limited, but includes, for example, an organic group, a hydroxy group, a halogen atom, an amino group (the amino group may have a substituent, and the substituents include the above-mentioned organic group W). etc.). Examples of the organic group include the organic group W described above.
The substituents represented by R ^C6 to R ^C9 are not particularly limited, but include, for example, an organic group, a hydroxy group, a halogen atom, an amino group (the amino group may have a substituent, and the substituents include the above-mentioned organic groups). and the like. Examples of the organic group include the organic group W described above.
The divalent linking group represented by L ^C1 is not particularly limited, but may include an alkylene group, -S-, -O-, -SO-, -SO ₂ -, -CO-, -NR ^C10 -, or two of these. A linking group formed by a combination of the above is preferred. R ^C10 represents a hydrogen atom or an organic group. Examples of the organic group include the organic group W described above.

As the thiol compound, aromatic thiol compounds are preferred. The aromatic thiol compound is preferably a compound in which a thiol group is bonded to an aromatic group, and examples of the aromatic group include an aryl group and a heteroaryl group, and examples of the aryl group and heteroaryl group include the above-mentioned organic group W. Examples include aryl groups and heteroaryl groups exemplified in .
As the phosphorus compound, a phosphite compound is preferable, and an aromatic phosphite compound is more preferable. Examples of the aromatic group contained in the aromatic phosphite compound include an aryl group and a heteroaryl group, and examples of the aryl group and heteroaryl group include the aryl group and heteroaryl group exemplified in the above-mentioned organic group W. .
As the sugar compound, ascorbic acid is preferred.
As the nitro compound and nitroso compound, aromatic nitro compounds and aromatic nitroso compounds are preferred. The aromatic ring contained in the aromatic nitro compound and the aromatic nitroso compound is preferably an aromatic hydrocarbon ring. The number of carbon atoms in the aromatic ring is preferably 6 to 20, more preferably 6 to 15. The aromatic ring may have a substituent, and examples of the substituent include an alkyl group, a cycloalkyl group, and a hydroxy group.
Further, as the compound (C), a compound represented by the following formula (CA-5) is also preferable.

In formula (CA-5), R ^C11 and R ^C12 each independently represent a hydrogen atom or an alkyl group. However, at least one of R ^C11 and R ^C12 represents an alkyl group. R ^C13 represents a substituent. c6 represents an integer from 0 to 3. When a plurality of R ^C13s exist, the plurality of R ^C13s may be the same or different. A plurality of R ^C13s may be bonded to each other to form a ring.
At least one of R ^C11 and R ^C12 is preferably an alkyl group having 1 to 10 carbon atoms, particularly preferably a t-butyl group.
When R ^C13 is an organic group, it is preferably an organic group having 1 to 100 carbon atoms, more preferably an organic group having 1 to 50 carbon atoms. Examples of R ^C13 include the organic group W described above.

It is particularly preferable that the compound (C) is at least one selected from the group consisting of a compound represented by the following formula (H-1) and a compound represented by the following formula (H-2).

In formula (H-1), R ^H1 represents a hydrogen atom, a hydroxy group, or an organic group, and R ^H2 to R ^H4 each independently represent a hydrogen atom or an organic group. Adjacent two of R ^H1 to R ^H4 may be bonded to each other to form a ring.
In formula (H-2), R ^H5 represents a hydrogen atom, a hydroxy group, or an organic group, and R ^H6 to R ^H8 each independently represent a hydrogen atom or an organic group. R ^H5 and R ^H6 may be bonded to each other to form a ring. R ^H7 and R ^H8 may be bonded to each other to form a ring.

In formula (H-1), the organic group represented by R ^H1 to R ^H4 includes the organic group W described above, and an organic group having 1 to 10 carbon atoms is preferable. As the organic group, an alkyl group, an alkenyl group, an alkoxy group, an acyl group, and an acyloxy group are more preferable.
The ring formed by bonding two adjacent ones of R ^H1 to R ^H4 to each other may be an aromatic ring or a non-aromatic ring, but a cyclohexane ring or a benzene ring is preferable, and a benzene ring is more preferable.
In formula (H-2), the organic group represented by R ^H5 to R ^H8 includes the organic group W described above, and an organic group having 1 to 10 carbon atoms is preferable. As the organic group, an alkyl group, an alkenyl group, an alkoxy group, an acyl group, and an acyloxy group are more preferable.
The ring formed by bonding R ^H5 and R ^H6 with each other, and the ring formed by bonding R ^H7 and R ^H8 with each other, may be aromatic rings or non-aromatic rings, but are preferably cyclohexane rings or benzene rings. A ring is more preferred.

Specific examples of compound (C) are shown below, but the invention is not limited thereto.

When the resist composition of the present invention contains compound (C), the content of compound (C) is preferably 0.5% by mass or more, and 1.0% by mass or more based on the total solid content of the resist composition. is more preferable, and even more preferably 2.0% by mass or more. Further, when the resist composition of the present invention contains compound (C), the content of compound (C) is preferably 30.0% by mass or less, and 20.0% by mass or less based on the total solid content of the resist composition. % or less, more preferably 10.0% by mass or less.
Compound (C) may be used alone or in combination. When two or more types are used, it is preferable that the total content is within the above-mentioned preferred content range.

<Specific group (D)>
When the resist composition of the present invention satisfies at least one of the above (2) and (3) (that is, at least one of the onium salt (A) and the polymer (B) contains at least one specific group (D)) case) will be explained.
Examples of the specific group (D) include groups known as antioxidant groups, polymerization termination groups, or chain transfer groups.
When the polymer (B) contains a specific group (D), the specific group (D) may also serve as an interactive group that interacts with the above-mentioned onium salt (A).
The specific group (D) is an aromatic group substituted with two or more hydroxy groups, an aromatic group substituted with one or more hydroxy groups and one or more carboxy groups, an amino group, a thiol group, a group containing a phosphorus atom, a carbon- A group containing a structure in which each of two carbon atoms of a carbon double bond is substituted with a hydroxy group, a nitro group, and a nitroso group, preferably containing at least one selected from the group consisting of a nitro group and a nitroso group, and two or more hydroxy groups. It is more preferable that the group contains at least one selected from the group consisting of a substituted aromatic group, a thiol group, and a nitroso group.

The aromatic group substituted with two or more hydroxy groups is preferably an aryl group substituted with two or more hydroxy groups, more preferably an aryl group having 6 to 20 carbon atoms substituted with two or more hydroxy groups, A phenyl group or naphthyl group substituted with two or more hydroxy groups is more preferred, and a phenyl group substituted with two or more hydroxy groups is particularly preferred. The number of hydroxy groups in the aromatic group substituted with two or more hydroxy groups is preferably 2 or more and 4 or less, more preferably 2 or 3.

The aromatic group substituted with one or more hydroxy group and one or more carboxy group is preferably an aryl group substituted with one or more hydroxy group and one or more carboxy group, and an aryl group substituted with one or more hydroxy group and one or more carboxy group each has 6 carbon atoms. -20 aryl groups are more preferred, phenyl or naphthyl groups each substituted with one or more hydroxy groups and one or more carboxy groups are even more preferred, and phenyl groups each substituted with one or more hydroxy groups and one or more carboxy groups are particularly preferred. The number of hydroxy groups and the number of carboxy groups in the aromatic group substituted with one or more hydroxy groups and one or more carboxy groups is preferably from 1 to 2, respectively.

The amino group is preferably a group containing -NR ^D1 - (excluding -CO-NR ^D1 -CO- and -NR ^D1 -SO ₂ -). R ^D1 represents a hydrogen atom or an organic group, and examples of the organic group include the organic group W described above. An amino group is a group formed by removing at least one of the hydrogen atoms contained in the compound represented by the above formula (CA-1), and a group formed by removing at least one hydrogen atom contained in the compound represented by the above formula (CA-2). A group formed by removing at least one of the atoms, a group formed by removing at least one hydrogen atom contained in the compound represented by the above formula (CA-3), and a group formed by removing at least one hydrogen atom from the compound represented by the above formula (CA-4). ) is preferably at least one selected from the group consisting of groups formed by removing at least one of the hydrogen atoms contained in the compound represented by ().

The thiol group is preferably a thiol group bonded to an aromatic group. Examples of the aromatic group include an aryl group and a heteroaryl group, and examples of the aryl group and heteroaryl group include the aryl group and heteroaryl group exemplified in the above-mentioned organic group W.
The group containing a phosphorus atom is preferably a group formed by removing at least one hydrogen atom contained in a phosphite compound, and a group formed by removing at least one hydrogen atom contained in an aromatic phosphite compound. More preferred are groups such as Examples of the aromatic group contained in the aromatic phosphite compound include an aryl group and a heteroaryl group, and examples of the aryl group and heteroaryl group include the aryl group and heteroaryl group exemplified in the above-mentioned organic group W. .

The group containing a structure in which two carbon atoms of a carbon-carbon double bond are each substituted with one hydroxy group is a group represented by the following formula (D-1).

In formula (D-1), each * represents a substitution position.
Further, as the specific group (D), a group formed by removing at least one of the hydrogen atoms contained in the compound represented by the above formula (CA-5) is preferable.

The specific group (D) is particularly preferably at least one selected from the group consisting of a group represented by the following formula (H-1S) and a group represented by the following formula (H-2S).

In formula (H-1S), R ^H1S represents a hydrogen atom, a hydroxy group, or an organic group, and R ^H2S to R ^H4S each independently represent a hydrogen atom or an organic group. Adjacent two of R ^H1S to R ^H4S may be bonded to each other to form a ring. However, at least one hydrogen atom contained in R ^H1S to R ^H4S and a hydrogen atom contained in a ring formed by bonding two adjacent ones of R ^H1S to R ^H4S to each other is removed to form a group. .
In formula (H-2S), R ^H5S represents a hydrogen atom, a hydroxy group or an organic group, and R ^H6S to R ^H8S each independently represent a hydrogen atom or an organic group. R ^H5S and R ^H6S may be combined with each other to form a ring. R ^H7S and R ^H8S may be combined with each other to form a ring. However, hydrogen atoms contained in R ^H5S to R ^H8S , hydrogen atoms contained in the ring formed by combining R ^H5S and R ^H6S , and hydrogen atoms contained in the ring formed by combining R ^H7S and R ^H8S , At least one hydrogen atom is removed to form a group.

Specific examples and preferred ranges of R ^H1S to R ^H4S in formula (H-1S) are the same as R ^H1 to R ^H4 in formula (H-1) described above.
Specific examples and preferred ranges of R ^H5S to R ^H8S in formula (H-2S) are the same as R ^H5 to R ^H8 in formula (H-2) described above.
The group represented by the above formula (H-1S) and the group represented by the above formula (H-2S) are preferably monovalent groups.

When the resist composition of the present invention satisfies at least (2) above (that is, when at least one onium salt (A) contains at least one specific group (D)), the onium salt containing the specific group (D) ( The content of A) is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 5.0% by mass or more, based on the total solid content of the resist composition. Further, the content is preferably 40.0% by mass or less, more preferably 30.0% by mass or less.

When the resist composition of the present invention satisfies at least the above (3) (that is, when at least one polymer (B) contains at least one specific group (D)), the polymer (B) contains the specific group ( It is preferable to include a repeating unit having D).
In the polymer (B), the content of the repeating unit having the specific group (D) is preferably 20 mol% or more, more preferably 30 mol% or more, and 40 mol% or more, based on the total repeating units. More preferably, it is mol% or more. Further, the content of repeating units having the specific group (D) is preferably 80 mol% or less, more preferably 70 mol% or less, and 60 mol% or less based on all repeating units. It is even more preferable.
In the polymer (B), one type of repeating unit having the specific group (D) may be contained alone, or two or more types may be contained. When two or more types are included, the total content is preferably within the above-mentioned preferred content range.

<Solvent>
The resist composition of the present invention preferably contains a solvent.
The solvent consists of (M1) propylene glycol monoalkyl ether carboxylate, and (M2) propylene glycol monoalkyl ether, lactic acid ester, acetate ester, alkoxypropionic acid ester, chain ketone, cyclic ketone, lactone, and alkylene carbonate. Preferably, at least one selected from the group . Note that this solvent may further contain components other than components (M1) and (M2).

When such a solvent and polymer (B) are used in combination, the coatability of the resist composition is improved and a pattern with a small number of development defects is easily formed. The reason for this is that these solvents have an excellent balance between the solubility, boiling point, and viscosity of the polymer (B), so they can reduce unevenness in the thickness of the resist film, which is a composition film of the resist composition, and precipitates during spin coating. This is presumed to be due to the ability to suppress the occurrence of.

Component (M1) is preferably at least one selected from the group consisting of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, and propylene glycol monoethyl ether acetate; Glycol monomethyl ether acetate (PGMEA) is more preferred.

As component (M2), the following are preferable.
As the propylene glycol monoalkyl ether, propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether (PGEE) are preferable.
As the lactic acid ester, ethyl lactate, butyl lactate, or propyl lactate is preferable.
As the acetic acid ester, methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, isoamyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, or 3-methoxybutyl acetate is preferred.
Butyl butyrate is also preferred.
As the alkoxypropionate ester, methyl 3-methoxypropionate (MMP) or ethyl 3-ethoxypropionate (EEP) is preferable.
Examples of chain ketones include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, phenylacetone, methyl ethyl ketone, and methyl isobutyl. Ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methylnaphthyl ketone, or methyl amyl ketone is preferred.
As the cyclic ketone, methylcyclohexanone, isophorone, cyclopentanone, or cyclohexanone is preferred.
As the lactone, γ-butyrolactone is preferred.
As the alkylene carbonate, propylene carbonate is preferred.

Component (M2) is more preferably propylene glycol monomethyl ether (PGME), ethyl lactate, ethyl 3-ethoxypropionate, methyl amyl ketone, cyclohexanone, butyl acetate, pentyl acetate, γ-butyrolactone, or propylene carbonate.

In addition to the above-mentioned components, the solvent may include an ester solvent having 7 or more carbon atoms (preferably 7 to 14, more preferably 7 to 12, even more preferably 7 to 10) and having 2 or less heteroatoms. It is also preferable to include.
Examples of ester solvents having 7 or more carbon atoms and 2 or less heteroatoms include amyl acetate, 2-methylbutyl acetate, 1-methylbutyl acetate, hexyl acetate, pentyl propionate, hexyl propionate, butyl propionate, and isobutyl isobutyrate. , heptyl propionate, or butyl butanoate are preferred, and isoamyl acetate is more preferred.

The component (M2) preferably has a flash point (hereinafter also referred to as fp) of 37° C. or higher. Such components (M2) include propylene glycol monomethyl ether (fp: 47°C), ethyl lactate (fp: 53°C), ethyl 3-ethoxypropionate (fp: 49°C), and methyl amyl ketone (fp: 42°C). ), cyclohexanone (fp: 44°C), pentyl acetate (fp: 45°C), methyl 2-hydroxyisobutyrate (fp: 45°C), γ-butyrolactone (fp: 101°C), or propylene carbonate (fp: 132°C) is preferred. Among these, propylene glycol monoethyl ether, ethyl lactate, pentyl acetate, or cyclohexanone are more preferred, and propylene glycol monoethyl ether or ethyl lactate is even more preferred.
In addition, the "flash point" here means the value described in the reagent catalog of Tokyo Chemical Industry Co., Ltd. or Sigma-Aldrich.

Preferably, the solvent contains component (M1). It is more preferable that the solvent consists essentially of component (M1) only, or is a mixed solvent of component (M1) and other components. In the latter case, it is more preferable that the solvent contains both component (M1) and component (M2).
The mass ratio (M1/M2) of component (M1) and component (M2) is preferably within the range of "100/0" to "15/85", and is preferably within the range of "100/0" to "40/60". ”, and even more preferably within the range of “100/0” to “60/40”. That is, it is preferable that the solvent consists only of component (M1) or contains both component (M1) and component (M2), and the mass ratio thereof is as follows. That is, in the latter case, the mass ratio of component (M1) to component (M2) is preferably 15/85 or more, more preferably 40/60 or more, and even more preferably 60/40 or more. preferable. If such a configuration is adopted, it becomes possible to further reduce the number of development defects.

Note that when the solvent contains both component (M1) and component (M2), the mass ratio of component (M1) to component (M2) is, for example, 99/1 or less.

When the solvent further contains components other than components (M1) and (M2), the content of components other than components (M1) and (M2) is preferably 5 to 30% by mass based on the total amount of the solvent.

The content of the solvent in the resist composition of the present invention is preferably determined so that the solid content concentration is 0.5 to 30% by mass, and 1 to 20% by mass in terms of better coating properties. It is more preferable to set

<Surfactant>
The resist composition of the present invention may contain a surfactant. When a surfactant is included, a pattern with better adhesion and fewer development defects can be formed.
The surfactant is preferably a fluorine-based and/or silicon-based surfactant.
Examples of the fluorine-based and/or silicon-based surfactants include the surfactants disclosed in paragraphs [0218] and [0219] of International Publication No. 2018/193954.
One type of surfactant may be used alone, or two or more types may be used in combination.
When the resist composition of the present invention contains a surfactant, the content of the surfactant is preferably 0.0001 to 2% by mass, and 0.0005 to 1% by mass based on the total solid content of the composition. More preferred.

[Resist film, pattern formation method]
Although the procedure of the pattern forming method using the above resist composition is not particularly limited, it is preferable to include the following steps.
Step 1: Step of forming a resist film on a substrate using a resist composition Step 2: Step of exposing the resist film Step 3: Step of developing the exposed resist film using a developer containing an organic solvent The following , the procedure of each of the above steps will be explained in detail.

<Step 1: Resist film formation step>
Step 1 is a step of forming a resist film on a substrate using a resist composition.
The resist composition is as described above.

Examples of methods for forming a resist film on a substrate using a resist composition include a method of applying a resist composition onto a substrate.
Note that it is preferable to filter the resist composition as necessary before coating. The pore size of the filter is preferably 0.1 μm or less, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less. Moreover, the filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

The resist composition can be applied onto a substrate (eg, silicon, silicon dioxide coated), such as those used in the manufacture of integrated circuit devices, by any suitable application method, such as a spinner or coater. The coating method is preferably spin coating using a spinner. The rotation speed during spin coating using a spinner is preferably 1000 to 3000 rpm (rotations per minute).
After applying the resist composition, the substrate may be dried to form a resist film. Note that, if necessary, various base films (an inorganic film, an organic film, an antireflection film) may be formed under the resist film.

Examples of the drying method include a method of drying by heating. Heating can be carried out using a means provided in an ordinary exposure machine and/or developing machine, or may be carried out using a hot plate or the like. The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, even more preferably 80 to 130°C. The heating time is preferably 30 to 1000 seconds, more preferably 60 to 800 seconds, even more preferably 60 to 600 seconds.

The thickness of the resist film is not particularly limited, but is preferably 10 to 120 nm from the standpoint of forming fine patterns with higher precision. Among these, in the case of EUV exposure and EB exposure, the thickness of the resist film is more preferably 10 to 65 nm, and even more preferably 15 to 50 nm. Further, in the case of ArF immersion exposure, the thickness of the resist film is more preferably 10 to 120 nm, and even more preferably 15 to 90 nm.

Note that a top coat may be formed on the upper layer of the resist film using a top coat composition.
Preferably, the top coat composition does not mix with the resist film and can be uniformly applied to the upper layer of the resist film. The top coat is not particularly limited, and a conventionally known top coat can be formed by a conventionally known method. Can be formed.
For example, it is preferable to form a top coat containing a basic compound as described in JP-A-2013-061648 on the resist film.
It is also preferable that the top coat contains a compound containing at least one group or bond selected from the group consisting of an ether bond, a thioether bond, a hydroxyl group, a thiol group, a carbonyl bond, and an ester bond.

<Step 2: Exposure step>
Step 2 is a step of exposing the resist film.
Examples of the exposure method include a method of irradiating the formed resist film with actinic rays or radiation through a predetermined mask.
Actinic light or radiation includes infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, and electron beams, preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to Deep ultraviolet light with a wavelength of 200 nm, specifically KrF excimer laser (248 nm), ArF excimer laser (193 nm), _F2 excimer laser (157 nm), EUV (13 nm), X-rays, and electron beams.

After exposure, it is preferable to perform post-exposure heat treatment (also referred to as post-exposure bake) before development. The post-exposure heat treatment accelerates the reaction in the exposed area, resulting in better sensitivity and pattern shape.
The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, even more preferably 80 to 130°C.
The heating time is preferably 10 to 1000 seconds, more preferably 10 to 180 seconds, and even more preferably 30 to 120 seconds.
Heating can be carried out using means provided in a normal exposure machine and/or developing machine, and may be carried out using a hot plate or the like.

<Step 3: Development step>
Step 3 is a step of developing the exposed resist film using a developer to form a pattern.
The developer is a developer containing an organic solvent (hereinafter also referred to as an organic developer).

Development methods include, for example, a method in which the 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 the substrate is left still for a certain period of time for development (paddle method). ), a method of spraying the developer onto the substrate surface (spray method), and a method of continuously discharging the developer while scanning the developer discharge nozzle at a constant speed onto the rotating substrate (dynamic dispensing method). can be mentioned.
Furthermore, after the step of developing, a step of stopping the development may be carried out while substituting another solvent.
The development time is not particularly limited as long as the resin in the unexposed areas is sufficiently dissolved, and is preferably 10 to 300 seconds, more preferably 20 to 120 seconds.
The temperature of the developer is preferably 0 to 50°C, more preferably 15 to 35°C.

The organic developer is a developer containing at least one organic solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents. It is preferable to have one.

A plurality of the above-mentioned solvents may be mixed together, or may be mixed with a solvent other than the above-mentioned ones or water. The water content of the developer as a whole is preferably less than 50% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, and particularly preferably substantially free of water.
The content of the organic solvent in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and 90% by mass or more and 100% by mass, based on the total amount of the developer. The following is more preferable, and 95% by mass or more and 100% by mass or less is particularly preferable.

<Other processes>
The pattern forming method preferably includes a step of cleaning using a rinsing liquid after step 3.

The rinsing solution used in the rinsing step after the development step using an organic developer is not particularly limited as long as it does not dissolve the pattern, and solutions containing common organic solvents can be used. The rinsing liquid contains at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents. is preferred.

The method of the rinsing process is not particularly limited, and examples include a method in which the rinsing liquid is continuously discharged onto the substrate rotating at a constant speed (rotary coating method), and a method in which the substrate is immersed in a tank filled with the rinsing liquid for a certain period of time. (dip method), and a method of spraying a rinsing liquid onto the substrate surface (spray method).
Further, the pattern forming method of the present invention may include a heating step (Post Bake) after the rinsing step. In this step, the developer and rinse solution remaining between patterns and inside the patterns due to baking are removed. This step also has the effect of smoothing the resist pattern and improving surface roughness of the pattern. The heating step after the rinsing step is usually carried out at 40 to 250°C (preferably 90 to 200°C) for 10 seconds to 3 minutes (preferably 30 seconds to 120 seconds).

Further, the substrate may be etched using the formed pattern as a mask. That is, the pattern formed in step 3 may be used as a mask to process the substrate (or the lower film and the substrate) to form a pattern on the substrate.
The method of processing the substrate (or the lower layer film and the substrate) is not particularly limited, but by performing dry etching on the substrate (or the lower layer film and the substrate) using the pattern formed in step 3 as a mask, the substrate is processed. A method of forming a pattern is preferred. The dry etching is preferably oxygen plasma etching.

The resist composition and various materials used in the pattern forming method of the present invention (e.g., solvent, developer, rinsing liquid, composition for forming an antireflection film, composition for forming a top coat, etc.) do not contain impurities such as metals. Preferably, it does not contain. The content of impurities contained in these materials is preferably 1 mass ppm (parts per million) or less, more preferably 10 mass ppb (parts per billion) or less, even more preferably 100 mass ppt (parts per trillion) or less, and 10 mass ppm (parts per million) or less. A mass ppt or less is particularly preferred, and a mass ppt or less is most preferred. Here, examples of metal impurities include Na, K, Ca, Fe, Cu, Mg, Al, Li, Cr, Ni, Sn, Ag, As, Au, Ba, Cd, Co, Pb, Ti, V, Examples include W, and Zn.

Examples of methods for removing impurities such as metals from various materials include filtration using a filter. Details of filtration using a filter are described in paragraph [0321] of International Publication No. 2020/004306.

In addition, methods for reducing impurities such as metals contained in various materials include, for example, selecting raw materials with low metal content as raw materials constituting various materials, and filtering raw materials constituting various materials. and a method in which distillation is carried out under conditions where contamination is suppressed as much as possible by lining the inside of the apparatus with Teflon (registered trademark).

In addition to filter filtration, impurities may be removed using an adsorbent, or a combination of filter filtration and an adsorbent may be used. As the adsorbent, known adsorbents can be used, such as inorganic adsorbents such as silica gel and zeolite, and organic adsorbents such as activated carbon. In order to reduce impurities such as metals contained in the various materials mentioned above, it is necessary to prevent metal impurities from being mixed in during the manufacturing process. Whether metal impurities have been sufficiently removed from the manufacturing equipment can be confirmed by measuring the content of metal components contained in the cleaning liquid used to clean the manufacturing equipment. The content of metal components contained in the cleaning liquid after use is preferably 100 mass ppt or less, more preferably 10 mass ppt or less, and even more preferably 1 mass ppt or less.

Further, the resist composition may contain water as an impurity. When water is contained as an impurity, the water content is preferably as small as possible, but may be contained in an amount of 1 to 30,000 ppm by mass based on the entire resist composition.
Further, the resist composition may contain residual monomers (for example, monomers derived from raw material monomers used in the synthesis of polymer (B)) as impurities. When a residual monomer is contained as an impurity, the content of the residual monomer is preferably as small as possible, but it may be contained in an amount of 1 to 30,000 ppm by mass based on the total solid content of the resist composition.

Conductive compounds are added to organic processing solutions such as rinse solutions to prevent damage to chemical piping and various parts (filters, O-rings, tubes, etc.) due to static electricity charging and subsequent electrostatic discharge. You may. The conductive compound is not particularly limited, and for example, methanol may be mentioned. The amount added is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less in terms of maintaining favorable development characteristics or rinsing characteristics.
Examples of chemical liquid piping include SUS (stainless steel), polyethylene or polypropylene treated with antistatic treatment, or various types of piping coated with fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.). can be used. Similarly, for the filter and O-ring, antistatically treated polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.) can be used.

[Manufacturing method of electronic device]
The present invention also relates to an electronic device manufacturing method including the above-described pattern forming method, and an electronic device manufactured by this manufacturing method.
The electronic device of the present invention is preferably installed in electrical and electronic equipment (home appliances, office automation (OA), media-related equipment, optical equipment, communication equipment, etc.).

The present invention will be described in more detail below based on Examples. The materials, usage amounts, proportions, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the Examples shown below.

[Components of actinic ray-sensitive or radiation-sensitive resin composition]
The components used in the actinic ray-sensitive or radiation-sensitive resin compositions (resist compositions) of Examples and Comparative Examples will be explained.

[Polymer]
The polymers shown in Table 3 (B-1 to B-20, BR-1 to BR-3) were synthesized by known methods. Note that B-1 to B-20 correspond to polymers (B), and BR-1 to BR-3 do not correspond to polymers (B).
Table 3 shows the type and content of each repeating unit in polymers B-1 to B-20 and BR-1 to BR-3. The content of each repeating unit is the molar ratio (mol%) of each repeating unit to all repeating units. The type of each repeating unit was indicated by the type of monomer corresponding to each repeating unit. The structure of each monomer is as described above.
Table 3 also lists the weight average molecular weight (Mw) and degree of dispersion (Mw/Mn) of each polymer.
The weight average molecular weight (Mw) and degree of dispersion (Mw/Mn) of the polymer were measured by GPC (carrier: tetrahydrofuran (THF)) (the amount is in terms of polystyrene). Further, the content of each repeating unit in the polymer was measured by ¹³ C-NMR (Nuclear Magnetic Resonance).

[Onium salt]
The onium salts used in each of the resist compositions in Tables 4 and 5 below, except for AX-1 and AX-2, are those listed above as specific examples of onium salts (A). AX-1 and AX-2 are onium salts each having the following structure. AX-2 was synthesized by a known method. The content of each repeating unit of AX-2 is a molar ratio to all repeating units. The weight average molecular weight (Mw) and dispersity (Mw/Mn) of AX-2 are also shown below. Mw and Mw/Mn of AX-2 were measured by GPC (carrier: THF) (the amount is equivalent to polystyrene). Further, the content of each repeating unit of AX-2 was measured by ¹³ C-NMR.
Since the pKa of the conjugate acid of the anion contained in AX-1 is -1.9, AX-1 does not correspond to an onium salt (A).
Since the pKa of the conjugate acid of the anion contained in AX-2 is 4.20, AX-2 corresponds to an onium salt (A). AX-2 does not fall under polymer (B).
The onium salts used in Examples and Comparative Examples all correspond to photodegradable onium salt compounds.

[Compound (C)]
The compound (C) used in each of the resist compositions in Tables 4 and 5 below is listed above as a specific example of compound (C).

〔solvent〕
The solvents used are shown below.
G1: Propylene glycol monomethyl ether acetate (PGMEA)
G2: Propylene glycol monomethyl ether (PGME)
G3: Ethyl lactate G4: Cyclopentanone

[Preparation of resist composition]
Components other than the solvents shown in Tables 4 and 5 below were mixed with the solvents shown in Tables 4 and 5 below so that the solid content concentration was 1.3% by mass. Next, the resulting mixed solution was filtered through a polyethylene filter having a pore size of 0.03 μm to prepare resist compositions (Re-1 to Re-30, Hre-1 to Hre-7). Here, solid content means all components other than the solvent. The obtained resist compositions were used in Examples and Comparative Examples.
Tables 4 and 5 below list the types and contents of each component used (mass ratio (mass %) to the total solid content of the resist composition). In addition, Tables 4 and 5 below list the types and mixing ratios (mass ratios) of the solvents used. Furthermore, Tables 4 and 5 below also indicate the presence or absence of the specific group (D) in the polymer and the presence or absence of the specific group (D) in the onium salt.

[Pattern formation and evaluation]
[Pattern formation and evaluation by EUV exposure: Examples 1 to 30, Comparative Examples 1 to 7]
<Pattern formation>
A lower layer film forming composition SHB-A940 (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied onto a silicon wafer and baked at 205° C. for 60 seconds to form a lower layer film with a thickness of 20 nm. Resist compositions shown in Tables 4 and 5 below were applied thereon and baked at 100° C. for 60 seconds to form a resist film with a thickness of 30 nm. As a result, a silicon wafer having a resist film was formed.
A silicon wafer having a resist film obtained by the above procedure was exposed using an EUV exposure device (manufactured by Exitech, Micro Exposure Tool, NA 0.3, Quadrupol, outer sigma 0.68, inner sigma 0.36). Pattern irradiation was performed. Note that a mask with a line size of 20 nm and a line:space ratio of 1:1 was used as the reticle.
The exposed resist film was baked at 90° C. for 60 seconds, developed with butyl acetate for 30 seconds, rinsed with butyl acetate, and spin-dried to obtain a pattern.

[Resolution (limit resolution, nm)]
In the above <Pattern formation>, exposure is performed at the optimum exposure amount Eop (μC/cm ² ) (the exposure amount at which the pattern formed using the resist composition reproduces the pattern of the mask used for exposure). ing.
Next, a test was conducted in which a line and space pattern was formed by gradually changing the exposure amount from the optimum exposure amount Eop. At this time, the minimum dimension of the pattern that could be resolved without collapsing was determined using a length-measuring scanning electron microscope (SEM (S-9380II, manufactured by Hitachi, Ltd.)). This was defined as "limit resolution (nm)". The smaller the limit resolution value, the better the resolution.
Resolution evaluation is preferably 20.0 nm or less, more preferably 18.0 nm or less, even more preferably 16.0 nm or less, even more preferably 14.0 nm or less, particularly preferably 12.0 nm or less, and 11.0 nm or less. is most preferred.

[LWR performance (nm)]
The pattern obtained in the above <Pattern Formation> was observed from above the pattern using a length-measuring scanning electron microscope (SEM (S-9380II, manufactured by Hitachi, Ltd.)). The line width of the pattern was observed at 250 locations, and its standard deviation (σ) was determined. Measurement variations in line width were evaluated using 3σ, and the value of 3σ was defined as LWR (nm). The smaller the LWR value, the better the LWR performance.
LWR is preferably 4.2 nm or less, more preferably 3.9 nm or less, even more preferably 3.7 nm or less, even more preferably 3.5 nm or less, particularly preferably 3.3 nm or less, and most preferably 3.0 nm or less. .

From the results shown in Tables 4 and 5, it was found that the resist compositions of Examples had better resolution and LWR performance of the formed patterns than the resist compositions of Comparative Examples.

[Pattern formation and evaluation by EB exposure: Examples 1A to 30A]
Even when a resist film was formed using each of the resist compositions of Examples and pattern formation was performed by exposing it to electron beams, results with the same tendency as when pattern formation was performed by EUV exposure were obtained. It was done.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application (Japanese Patent Application No. 2022-122349) filed on July 29, 2022, the contents of which are incorporated herein by reference.

Claims

(A) an onium salt containing an anion whose conjugate acid has a pKa of 2 or more, and
(B) A compound different from the onium salt (A), containing a repeating unit having an interactive group that interacts with the onium salt (A), and whose main chain is decomposed by irradiation with actinic rays or radiation. including a polymer;
An actinic ray-sensitive or radiation-sensitive resin composition that satisfies at least one of the following (1) to (3).
(1) The actinic ray-sensitive or radiation-sensitive resin composition contains at least one selected from the group consisting of antioxidants, polymerization inhibitors, and chain transfer agents.
(2) The onium salt (A) contains at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.
(3) The polymer (B) contains at least one selected from the group consisting of an antioxidant group, a polymerization termination group, and a chain transfer group.
The above-mentioned (1) is satisfied, and at least one selected from the group consisting of the antioxidant, polymerization inhibitor, and chain transfer agent is a polyhydric phenol compound, an amine compound, a thiol compound, a phosphorus compound, a sugar compound, a nitro compound, and a nitrosol compound. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, which is at least one selected from the group consisting of compounds.
3. The at least one selected from the group consisting of antioxidants, polymerization inhibitors, and chain transfer agents is at least one selected from the group consisting of polyhydric phenol compounds, thiol compounds, and nitroso compounds. Actinic ray-sensitive or radiation-sensitive resin composition.
At least one selected from the group consisting of the antioxidant, polymerization inhibitor, and chain transfer agent is a group consisting of a compound represented by the following formula (H-1) and a compound represented by the following formula (H-2). The actinic ray-sensitive or radiation-sensitive resin composition according to claim 2 or 3, which is at least one selected from the following.

In formula (H-1), R H1 represents a hydrogen atom, a hydroxy group, or an organic group, and R H2 to R H4 each independently represent a hydrogen atom or an organic group. Adjacent two of R H1 to R H4 may be bonded to each other to form a ring.
In formula (H-2), R H5 represents a hydrogen atom, a hydroxy group, or an organic group, and R H6 to R H8 each independently represent a hydrogen atom or an organic group. R H5 and R H6 may be bonded to each other to form a ring. R H7 and R H8 may be bonded to each other to form a ring.
an aromatic group that satisfies at least one of the above (2) and (3), and at least one selected from the group consisting of the antioxidant group, polymerization termination group, and chain transfer group is substituted with two or more hydroxy groups; Aromatic groups substituted with one or more hydroxy groups and one or more carboxy groups, amino groups, thiol groups, groups containing phosphorus atoms, structures in which two carbon atoms of a carbon-carbon double bond are each substituted with one hydroxy group The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, which contains at least one selected from the group consisting of a group containing , a nitro group, and a nitroso group.
At least one selected from the group consisting of the antioxidant group, polymerization termination group, and chain transfer group is at least one selected from the group consisting of an aromatic group substituted with two or more hydroxy groups, a thiol group, and a nitroso group. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 5, comprising:
At least one selected from the group consisting of the antioxidant group, polymerization termination group, and chain transfer group is a group consisting of a group represented by the following formula (H-1S) and a group represented by the following formula (H-2S). The actinic ray-sensitive or radiation-sensitive resin composition according to claim 5 or 6, which is at least one selected from the following.

In formula (H-1S), R H1S represents a hydrogen atom, a hydroxy group, or an organic group, and R H2S to R H4S each independently represent a hydrogen atom or an organic group. Adjacent two of R H1S to R H4S may be bonded to each other to form a ring. However, at least one hydrogen atom contained in R H1S to R H4S and a hydrogen atom contained in a ring formed by bonding two adjacent ones of R H1S to R H4S to each other is removed to form a group. .
In formula (H-2S), R H5S represents a hydrogen atom, a hydroxy group or an organic group, and R H6S to R H8S each independently represent a hydrogen atom or an organic group. R H5S and R H6S may be combined with each other to form a ring. R H7S and R H8S may be combined with each other to form a ring. However, hydrogen atoms contained in R H5S to R H8S , hydrogen atoms contained in the ring formed by combining R H5S and R H6S , and hydrogen atoms contained in the ring formed by combining R H7S and R H8S , At least one hydrogen atom is removed to form a group.
3. The conjugate acid of the anion contained in the onium salt (A) is at least one selected from the group consisting of a phenolic compound, a carboxylic acid, an imidic acid, a sulfonimidic acid, and a thiol compound. Actinic ray-sensitive or radiation-sensitive resin composition.
The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the onium salt (A) is at least one selected from the group consisting of sulfonium salts and iodonium salts.
The actinic ray-sensitive or radiation-sensitive resin according to claim 1, wherein the polymer (B) contains a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2). Composition.

In formula (1), X represents a halogen atom. R 0 and A 1 each independently represent a hydrogen atom or an organic group. L 1 represents -O- or -NR 1 -. R 1 represents a hydrogen atom or an organic group. R 0 and A 1 or R 1 may be bonded to each other to form a ring.
In formula (2), Y represents a hydrogen atom or a hydrocarbon group. A 2 represents an organic group.
However, at least one of A 1 and A 2 has an interactive group that interacts with the onium salt (A).
The repeating unit represented by the formula (2) is at least one selected from the group consisting of repeating units represented by the following formula (2)-1 to repeating units represented by the following formula (2)-4. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 10.

In formula (2)-1, Y represents a hydrogen atom or a hydrocarbon group. Ar represents an aryl group.
In formula (2)-2, Y represents a hydrogen atom or a hydrocarbon group. L 2 represents a single bond or -CO-. R a represents a hydrocarbon group.
In formula (2)-3, Y represents a hydrogen atom or a hydrocarbon group. R b and R c each independently represent a hydrocarbon group. R b and R c may be combined with each other to form a ring.
In formula (2)-4, Y represents a hydrogen atom or a hydrocarbon group. L 3 represents -O- or -NR e -. R e represents a hydrogen atom or an organic group. R d represents a hydrocarbon group.
The interactive group that the polymer (B) has and interacts with the onium salt (A) is at least one selected from the group consisting of a hydroxy group, a carboxy group, an imide group, a sulfonimide group, and a thiol group. , the actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2.
The polymer (B) contains a repeating unit having an interactive group that interacts with the onium salt (A),
The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the repeating unit has two or more interactive groups that interact with the onium salt (A).
The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the polymer (B) contains a repeating unit represented by the following formula (3).

In formula (3), k represents an integer from 2 to 5. A 3 represents an interactive group that interacts with the onium salt (A). A plurality of A3s may be the same or different. L 4 represents a single bond or a connecting group. A plurality of L 4 may be the same or different. A plurality of L 4 may be bonded to each other to form a ring.
The actinic ray-sensitive ray according to claim 1 or 2, wherein the polymer (B) contains a repeating unit represented by the following formula (1)-1 and a repeating unit represented by the following formula (3)-1. radiation-sensitive resin composition.

In formula (1)-1, X represents a halogen atom. R f represents a hydrogen atom or an organic group.
In formula (3)-1, Z 1 represents a hydroxy group or a carboxy group.
A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2.
A step of forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2;
a step of exposing the resist film;
Developing the exposed resist film using a developer containing an organic solvent;
A pattern forming method comprising:
A method for manufacturing an electronic device, comprising the pattern forming method according to claim 17.