JP7821782B2 - Actinic ray-sensitive or radiation-sensitive resin composition, resist film, pattern forming method, method for manufacturing electronic device, polymerizable compound, resin - Google Patents

Description

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

Since the development of resists for KrF excimer lasers (248 nm), pattern formation methods utilizing chemical amplification have been used to compensate for the loss of sensitivity due to light absorption. For example, in positive-tone chemical amplification methods, a photoacid generator contained in the exposed area is first decomposed by light irradiation to generate an acid. Then, during a post-exposure bake (PEB) process or the like, the catalytic action of the generated acid changes the alkali-insoluble groups of the resin contained in the actinic ray-sensitive or radiation-sensitive resin composition to alkali-soluble groups, thereby changing the solubility in a developer. Development is then performed, for example, using a basic aqueous solution. This removes the exposed area, resulting in the desired pattern.
To achieve miniaturization of semiconductor elements, the wavelength of exposure light sources has become shorter and the numerical aperture (NA) of projection lenses has become higher, and currently, exposure machines using ArF excimer lasers with a wavelength of 193 nm as a light source have been developed. In addition, pattern formation methods using extreme ultraviolet (EUV light) and electron beams (EB) as light sources are also being considered.
Under these circumstances, various compositions have been proposed as actinic ray-sensitive or radiation-sensitive resin compositions.

For example, Patent Document 1 discloses a resist composition containing a resin including a structural unit derived from a compound represented by formula (I) and a structural unit of a predetermined structure, and an acid generator. In formula (I), ^R1 and ^R2 each independently represent a group having an acid labile group, and W represents an alicyclic hydrocarbon group of 5 to 18 carbon atoms which may have a substituent.

Japanese Patent Application Laid-Open No. 2020-154322

The present inventors have prepared and examined resist compositions with reference to Patent Document 1, and have found that there is room for further improvement in resolution and line width roughness (LWR) performance of the formed patterns.
Therefore, an object of the present invention is to provide an actinic ray-sensitive or radiation-sensitive resin composition that can form a pattern with excellent LWR performance and also has excellent resolution.
Another object of the present invention is to provide a resist film, a pattern forming method, and a method for producing an electronic device, which are related to the actinic ray-sensitive or radiation-sensitive resin composition.
Another object of the present invention is to provide a polymerizable compound and a resin that are suitable for use in the actinic ray-sensitive or radiation-sensitive resin composition.

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

[1] An actinic ray-sensitive or radiation-sensitive resin composition comprising a resin having a repeating unit derived from a polymerizable compound having an acid-decomposable group and a photoacid generator,
the polymerizable compound is a polymerizable compound whose homopolymer has a glass transition temperature of 220°C or higher,
an actinic ray-sensitive or radiation-sensitive resin composition, wherein the molar amount of the acid-decomposable group relative to the mass of the polymerizable compound is 3.40 mmol/g or more;
[2] The actinic ray-sensitive or radiation-sensitive resin composition according to [1], wherein the polymerizable compound contains at least one of an aromatic ring and an aliphatic heterocycle.
[3] The actinic ray-sensitive or radiation-sensitive resin composition according to [1] or [2], wherein the polymerizable compound has a polycyclic structure.
[4] The actinic ray-sensitive or radiation-sensitive resin composition according to [1] or [2], wherein the polymerizable compound is a polymerizable compound having an aliphatic heterocycle with a polycyclic structure, or a polymerizable compound having an aromatic ring.
[5] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [4], wherein the polymerizable compound has at least two acid-decomposable groups.
[6] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [5], wherein the polymerizable compound is an acrylic compound or a methacrylic compound.
[7] An actinic ray-sensitive or radiation-sensitive resin composition comprising a resin having a repeating unit derived from a polymerizable compound represented by general formula (1) described below and a photoacid generator.
[8] The actinic ray-sensitive or radiation-sensitive resin composition according to [7], wherein the polymerizable compound represented by the general formula (1) is a polymerizable compound represented by the general formula (3) described below.
[9] The actinic ray-sensitive or radiation-sensitive resin composition according to [7], wherein the polymerizable compound represented by the general formula (1) is a polymerizable compound represented by the general formula (4) described below.
[10] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [7] to [9], wherein at least two of R ^X1 to R ^X4 represent an acid-decomposable group.
[11] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [7] to [10], wherein the polymerizable compound is a polymerizable compound represented by general formula (5) described later.
[12] A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [11].
[13] A step of forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [11];
exposing the resist film to light;
and developing the exposed resist film using a developer.
[14] A method for manufacturing an electronic device, comprising the pattern forming method according to [13].
[15] A polymerizable compound represented by the general formula (1) described below.
[16] A resin having a repeating unit derived from a polymerizable compound represented by general formula (1) described below.

According to the present invention, it is possible to provide an actinic ray-sensitive or radiation-sensitive resin composition that can form a pattern having excellent LWR performance and also has excellent resolution.
Furthermore, according to the present invention, it is possible to provide a resist film, a pattern forming method, and a method for producing an electronic device, which are related to the actinic ray-sensitive or radiation-sensitive resin composition.
Furthermore, the present invention can provide a polymerizable compound and a resin that are suitable for use in the actinic ray-sensitive or radiation-sensitive resin composition.

1 is ^{a 1} H-NMR chart of M-55 synthesized in the Synthesis Examples section.

The present invention will be described in detail below.
The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.
In the present specification, when a group (atomic group) is described without specifying whether it is substituted or unsubstituted, it encompasses both unsubstituted and substituted groups, unless it is contrary to the spirit of the present invention. For example, the term "alkyl group" encompasses not only unsubstituted alkyl groups (unsubstituted alkyl groups) but also substituted alkyl groups (substituted alkyl groups). Furthermore, the term "organic group" in the present specification refers to a group containing at least one carbon atom.
Unless otherwise specified, the substituent is preferably a monovalent substituent.
As used herein, "actinic rays" or "radiation" refers to, for example, the bright line spectrum of a mercury lamp, far ultraviolet rays typified by excimer lasers, extreme ultraviolet rays (EUV light: Extreme Ultraviolet), X-rays, electron beams (EB), etc. As used herein, "light" refers to actinic rays or radiation.
Unless otherwise specified, the term "exposure" in this specification includes not only exposure using the bright line spectrum of a mercury lamp, far ultraviolet light typified by an excimer laser, extreme ultraviolet light (EUV light), and X-rays, but also drawing using particle beams such as electron beams and ion beams.
In this specification, the word "to" is used to mean that the numerical values before and after it are included as the lower limit and upper limit.
The bonding direction of divalent groups represented in this specification is not limited unless otherwise specified. For example, when Y is -COO- in a compound represented by the formula "X-Y-Z", Y may be -CO-O- or -O-CO-. In addition, the compound may be "X-CO-O-Z" or "X-O-CO-Z".

In this specification, (meth)acrylate refers to acrylate and methacrylate, and (meth)acrylic refers to acrylic and methacrylic.
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 a resin are defined as polystyrene-equivalent values measured by gel permeation chromatography (GPC) using a GPC apparatus (HLC-8120GPC manufactured by Tosoh Corporation) (solvent: tetrahydrofuran, flow rate (sample injection amount): 10 μL, column: TSK gel Multipore HXL-M manufactured by Tosoh Corporation, column temperature: 40° C., flow rate: 1.0 mL/min, detector: differential refractive index detector).

As used herein, the acid dissociation constant (pKa) refers to the pKa in aqueous solution, and is specifically a value calculated using the following software package 1 based on a database of Hammett's substituent constants and publicly available literature values. 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. A specific example of this method is a method of calculating the H ⁺ 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 literature, etc., and are not limited to these. There are several software programs that can perform DFT, and Gaussian 16 is an example.

As described above, the pKa in this specification refers to a value calculated using the software package 1 based on a database of Hammett's substituent constants and known literature values. However, if the pKa cannot be calculated by this method, a value obtained by Gaussian 16 based on DFT (density functional theory) will be used.
Furthermore, the pKa in this specification refers to the "pKa in an aqueous solution" as described above, but when the pKa in an aqueous solution cannot be calculated, the "pKa in a dimethyl sulfoxide (DMSO) solution" will be used.

As used herein, halogen atoms include, for example, fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[First embodiment of actinic ray-sensitive or radiation-sensitive resin composition]
The actinic ray-sensitive or radiation-sensitive resin composition of the present invention (hereinafter also referred to as the “resist composition of the first embodiment”) contains a resin (hereinafter also referred to as the “specific acid-decomposable resin A”) that has a repeating unit derived from a polymerizable compound that has an acid-decomposable group (hereinafter also referred to as the “specific monomer A”), and a photoacid generator.
Here, the above-mentioned specific monomer A is a polymerizable compound whose homopolymer has a glass transition temperature of 220° C. or higher, and the molar amount of acid-decomposable groups relative to the mass of the polymerizable compound (hereinafter also referred to as the "protecting group value") is 3.40 mmol/g or higher. In this specification, the glass transition temperature of the homopolymer of specific monomer A refers to a value measured by the method described below.
Due to the above-described configuration, the resist composition of the first embodiment is capable of forming a pattern with excellent resolution and LWR.

Although the mechanism of action of the resist composition of the first embodiment is not clear, the inventors of the present invention speculate as follows.
The specific acid-decomposable resin A contained in the resist composition of the first embodiment has a repeating unit derived from the specific monomer A. Because the homopolymer of the specific monomer A has a high glass transition temperature, the resist composition of the first embodiment containing the specific acid-decomposable resin A can form a pattern with high film strength. As a result, it is believed that the resist composition of the first embodiment has high resolution (in other words, a small limiting resolution (nm)). Furthermore, because the specific monomer A has a high protecting group value, a pattern formed using the resist composition of the first embodiment containing the specific acid-decomposable resin A can exhibit excellent dissolution contrast. As a result, it is believed that the pattern formed using the resist composition of the first embodiment has excellent LWR performance. In other words, it is presumed that due to the properties of the specific monomer A, the resist composition of the first embodiment has excellent high resolution, and the formed pattern has excellent LWR performance.
Hereinafter, a resist composition that has higher resolution and/or a pattern formed using the resist composition that has better LWR performance may also be referred to as "the effects of the present invention being better."

The resist composition of the first embodiment will be described in detail below.
The resist composition of the first embodiment may be a positive resist composition or a negative resist composition. Furthermore, it may be a resist composition for alkali development or a resist composition for organic solvent development.
The resist composition of the first embodiment is typically a chemically amplified resist composition.
First, the various components of the resist composition of the first embodiment will be described in detail below.

[Specified acid-decomposable resin A]
The resist composition of the first embodiment contains a resin having a repeating unit derived from a specific monomer A (specific acid-decomposable resin A).
The specific acid-decomposable resin A is a resin that decomposes under the action of an acid and has an increased polarity.
That is, in the pattern formation method using the resist composition of the first embodiment, typically, when an alkaline developer is used as the developer, a positive pattern is preferably formed, and when an organic developer is used as the developer, a negative pattern is preferably formed.

<<Specific Monomer A>>
First, the specific monomer A will be described below.
The specific monomer A is a polymerizable compound having an acid-decomposable group, and the glass transition temperature of its homopolymer is 220° C. or higher, and the protecting group value is 3.40 mmol/g or higher.

The acid-decomposable group means a group that decomposes under the action of an acid and has an increased polarity.
The specific acid-decomposable resin A formed from the specific monomer A having an acid-decomposable group has a repeating unit having an acid-decomposable group (hereinafter also referred to as an "acid-decomposable repeating unit"). Due to the presence of this acid-decomposable repeating unit, the specific acid-decomposable resin A exhibits the property of increasing its polarity under the action of acid, thereby increasing its solubility in an alkaline developer and decreasing its solubility in organic solvents.

The acid-decomposable group generally refers to a group that decomposes under the action of an acid to generate a polar group. The acid-decomposable group preferably has a structure in which a polar group is protected by a leaving group that is released under the action of an acid. The acid-decomposable group can be decomposed under the action of an acid to generate a polar group.
The polar group is preferably an alkali-soluble group, and examples thereof include acidic groups such as a carboxyl group, a phenolic hydroxyl group, a fluorinated alcohol group, a sulfonic acid group, a phosphate group, a sulfonamide group, a sulfonylimide group, an (alkylsulfonyl)(alkylcarbonyl)methylene group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group, a bis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imide group, a tris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylene group, as well as alcoholic hydroxyl groups.
Among these, as the polar group, a carboxyl group, a phenolic hydroxyl group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), or a sulfonic acid group is preferred, a phenolic hydroxyl group or a carboxyl group is more preferred, and a carboxyl group is even more preferred, in terms of better effects of the present invention.

Examples of the leaving group that is eliminated by the action of an acid include groups represented by formulae (Y1) to (Y4).
Formula (Y1): -C(Rx ₁ )(Rx ₂ )(Rx ₃ )
Formula (Y2): -C(=O)OC(Rx ₁ )(Rx ₂ )(Rx ₃ )
Formula (Y3): -C(R ₃₆ )(R ₃₇ )(OR ₃₈ )
Formula (Y4): -C(Rn)(H)(Ar)

In formula (Y1) and formula (Y2), _Rx1 to _Rx3 each independently represent an alkyl group (linear or branched), a cycloalkyl group (monocyclic or polycyclic), an aryl group (monocyclic or polycyclic), an aralkyl group, or an alkenyl group (linear or branched). If possible, these groups preferably have a fluorine atom or a group having a fluorine atom as a substituent.
When all of Rx ₁ to Rx ₃ are alkyl groups (linear or branched), it is preferable that at least two of Rx ₁ to Rx ₃ are methyl groups.
In particular, it is preferable that Rx ₁ to Rx ₃ each independently represent a linear or branched alkyl group, and it is more preferable that Rx ₁ to Rx ₃ each independently represent a linear alkyl group.
Two of Rx ₁ to Rx ₃ may be bonded to each other to form a ring (monocyclic or polycyclic).

The alkyl group of Rx ₁ to Rx ₃ is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group.
The cycloalkyl groups of Rx ₁ to Rx ₃ are preferably monocyclic cycloalkyl groups such as a cyclopentyl group or a cyclohexyl group, or polycyclic cycloalkyl groups such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group.
The aryl groups of Rx ₁ to Rx ₃ are preferably aryl groups having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.
The aralkyl groups of Rx ₁ to Rx ₃ are preferably aralkyl groups having 7 to 20 carbon atoms.
The alkenyl groups of Rx ₁ to Rx ₃ are preferably vinyl groups.
The ring formed by bonding two of Rx ₁ to Rx ₃ is preferably a cycloalkyl group. The cycloalkyl group formed by bonding two of Rx ₁ to Rx ₃ is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group, and more preferably a monocyclic cycloalkyl group having 5 to 6 carbon atoms.
In the cycloalkyl group formed by bonding two of _Rx1 to _Rx3 together, for example, one of the methylene groups constituting the ring may be replaced with a heteroatom such as an oxygen atom, a group having a heteroatom such as a carbonyl group, or a vinylidene group. Furthermore, in such a cycloalkyl group, one or more (for example, one or two) ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group.
In the group represented by formula (Y1) or formula (Y2), for example, an embodiment in which _Rx1 is a methyl group or an ethyl group, and _Rx2 and _Rx3 are bonded to form the above-mentioned cycloalkyl group is also preferred.
In addition, in formula (Y1) or formula (Y2), when two of Rx ₁ to Rx ₃ are bonded to form a cycloalkenyl group, and in the cycloalkenyl group, a vinylene group is present at a position adjacent to C (carbon atom) specified in "C(Rx ₁ )(Rx ₂ )(Rx ₃ )" in formula (Y1) or formula (Y2), the remaining one of Rx ₁ to Rx ₃ may be a hydrogen atom.

In formula (Y3), R ₃₆ to R ₃₈ each independently represent a hydrogen atom or an organic group. _{R 37} and R ₃₈ may be bonded to each other to form a ring. Examples of the organic group include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. It is also preferable that R ₃₆ is a hydrogen atom.
_{Examples of the alkyl group, cycloalkyl group, aryl group, aralkyl group, and alkenyl group represented by R to R in formula (Y3) include the same groups as those described above as the alkyl group, cycloalkyl group, aryl group, aralkyl group, and alkenyl group represented by Rx to Rx3 in formula (} Y1) and formula (Y2).
R ₃₇ and R ₃₈ may be bonded to each other to form a ring.
Furthermore, in an acid-decomposable repeating unit, R ₃₈ may be bonded to the main chain of the repeating unit, and in this case, R ₃₈ is preferably an alkylene group such as a methylene group.

As formula (Y3), a group represented by the following formula (Y3-1) is preferred.

Here, L ₁ and L ₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a group formed by combining these (for example, a group formed by combining an alkyl group and an aryl group).
M represents a single bond or a divalent linking group.
Q represents an alkyl group which may contain a heteroatom, a cycloalkyl group which may contain a heteroatom, an aryl group which may contain a heteroatom, an amino group, an ammonium group, a mercapto group, a cyano group, an aldehyde group, or a group combining these (for example, a group combining an alkyl group and a cycloalkyl group).
In the alkyl and cycloalkyl groups, for example, one of the methylene groups may be replaced with a heteroatom such as an oxygen atom or a group having a heteroatom such as a carbonyl group.
Preferably, one of L ₁ and L ₂ is a hydrogen atom, and the other is an alkyl group, a cycloalkyl group, an aryl group, or a group formed by combining an alkylene group and an aryl group.
At least two of Q, M, and _L1 may be bonded to form a ring (preferably a 5- or 6-membered ring). Q may be bonded to a part of the acid group protected by the group represented by formula (Y3-1) to form a ring. Furthermore, Q may be bonded to the main chain of the acid-decomposable repeating unit to form a ring.
From the viewpoint of miniaturizing the pattern, _L2 is preferably a secondary or tertiary alkyl group, and more preferably a tertiary alkyl group. Examples of secondary alkyl groups include an isopropyl group, a cyclohexyl group, and a norbornyl group, and examples of tertiary alkyl groups include a tert-butyl group and an adamantane group. In these embodiments, the Tg (glass transition temperature) and activation energy are increased, thereby ensuring film strength and suppressing fogging.

In formula (Y4), Ar represents an aromatic ring group. Rn represents an alkyl group, a cycloalkyl group, or an aryl group. Rn and Ar may be bonded to each other to form a non-aromatic ring. Ar is preferably an aryl group.

In order to achieve better acid decomposition properties of the acid-decomposable group repeating unit, when a non-aromatic ring is directly bonded to the polar group (or its residue) in the leaving group protecting the polar group, it is also preferable that the ring atom in the non-aromatic ring adjacent to the ring atom directly bonded to the polar group (or its residue) does not have a halogen atom such as a fluorine atom as a substituent.

Other leaving groups that are eliminated by the action of an acid include a 2-cyclopentenyl group having a substituent (such as an alkyl group), such as a 3-methyl-2-cyclopentenyl group, and a cyclohexyl group having a substituent (such as an alkyl group), such as a 1,1,4,4-tetramethylcyclohexyl group.

In terms of achieving superior effects of the present invention, one preferred embodiment of the acid-decomposable group is an acid-decomposable group represented by the following general formula (O1):

In formula (O1), R ¹¹ to R ¹³ each independently represent an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group. The alkyl group and the alkenyl group may be either linear or branched. The cycloalkyl group and the aryl group may be either monocyclic or polycyclic.
Two of R ¹¹ to R ¹³ may be bonded to each other to form a ring, but it is preferable that they do not form a ring in order to obtain better effects of the present invention.
* indicates a binding site.
It is particularly preferred that all of R ¹¹ to R ¹³ are alkyl groups (straight-chain or branched). When all of R ¹¹ to R ¹³ are alkyl groups (straight-chain or branched), it is preferred that at least two of R ¹¹ to R ¹³ are methyl groups.

The alkyl groups of R ¹¹ to R ¹³ are preferably alkyl groups having 1 to 4 carbon atoms.
The cycloalkyl group of R ¹¹ to R ¹³ is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group.
The aryl group of R ¹¹ to R ¹³ is preferably an aryl group having 6 to 10 carbon atoms.
The alkenyl group of R ¹¹ to R ¹³ is preferably a vinyl group.
The cycloalkyl group formed by bonding two of R ¹¹ to R ¹³ may be either monocyclic or polycyclic, but among these, a monocyclic cycloalkyl group is preferred, and a 5- or 6-membered monocyclic cycloalkyl group is more preferred. In addition, in the cycloalkyl group formed by bonding two of R ¹¹ to R ¹³ , for example, one of the methylene groups constituting the ring may be replaced with a heteroatom such as an oxygen atom, a group having a heteroatom such as a carbonyl group, or a vinylidene group. Furthermore, in these cycloalkyl groups, one or more of the ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group.

The alkyl group, cycloalkyl group, alkenyl group, and aryl group represented by R ¹¹ to R ¹³ may have a substituent. Examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6 carbon atoms).

The number of acid-decomposable groups in specific monomer A is not limited as long as it is one or more, but two or more is preferable in terms of achieving better effects of the present invention. There is no particular upper limit, but it is, for example, eight or less, preferably six or less, and more preferably four or less.

Specific monomer A is a polymerizable compound whose homopolymer has a glass transition temperature of 220°C or higher. In this specification, the glass transition temperature of the homopolymer of specific monomer A refers to the value measured by the following method.

<<Method for measuring the glass transition temperature (Tg (°C)) of a homopolymer of specific monomer A>>
<1> A copolymer P1 having a weight average molecular weight of 60,000 or more (preferably, a weight average molecular weight of 60,000 to 100,000) is obtained by synthesizing a copolymer P1 using a feed composition of 30 mass % of specific monomer A and 70 mass % of cyclohexyl methacrylate.
<2> The Tg of the obtained copolymer P1 is evaluated using a differential scanning calorimeter (DSC).
<3> Using the following formula (1) based on the Fox formula, the Tg of the homopolymer of specific monomer A is calculated, assuming that the Tg of the homopolymer of cyclohexyl methacrylate is 98°C.

Formula (1) 1/Tg=w1/Tg1+w2/Tg2
In formula (1), Tg represents the Tg(K) of the copolymer P1. Tg1 represents the Tg(K) of the homopolymer of specific monomer A. Tg2 represents the Tg(K) of the homopolymer of cyclohexyl methacrylate. w1 represents the mass fraction of repeating units derived from specific monomer A relative to all repeating units in copolymer P1. w2 represents the mass fraction of repeating units derived from the homopolymer of cyclohexyl methacrylate relative to all repeating units in copolymer P1. When calculating the Tg of the homopolymer of specific monomer A, w1 is set to 0.3 and w2 is set to 0.7.

As a differential scanning calorimeter, for example, the "DSC-60 Plus Measurement System" manufactured by Shimadzu Corporation can be used.

The glass transition temperature of the homopolymer of specific monomer A is preferably 220°C or higher, more preferably 250°C or higher, even more preferably 280°C or higher, and particularly preferably 300°C or higher, in order to achieve superior effects of the present invention. There is no particular upper limit, but a temperature of 400°C or lower is preferred.

The protecting group value of specific monomer A is 3.40 mmol/g or more. The protecting group value represents the molar amount (mmol/g) of acid-decomposable groups relative to the mass of specific monomer A (polymerizable compound). The upper limit is not particularly limited, but is preferably 6.0 mmol/g or less. In terms of achieving better effects of the present invention, the protecting group value is preferably 3.50 mmol/g or more, and more preferably 3.60 mmol/g or more.

The molecular weight of specific monomer A is not particularly limited, but is preferably 400 or more. The upper limit is preferably 1,000 or less, more preferably 800 or less, and even more preferably 700 or less.

The specific monomer A has a polymerizable group.
The type of polymerizable group is not particularly limited, and examples thereof include radically polymerizable groups and cationically polymerizable groups, with radically polymerizable groups being preferred and ethylenically unsaturated groups being more preferred.
Examples of types of ethylenically unsaturated groups include vinyl groups, maleimide groups, CH ₂ ═CR ^T - (R ^T represents a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, and iodine atom)), CH ₂ ═CR ^Q -CO-O- (R ^Q represents an alkyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, and iodine atom) or a hydrogen atom. When R ^Q represents a methyl group or a hydrogen atom, CH ₂ ═CR ^Q -CO-O- corresponds to a (meth)acrylic group, and when R ^Q represents a chlorine atom, CH ₂ ═CR ^Q -CO-O- corresponds to an α-chloroacrylic group), and the like. In view of the superior effects of the present invention, a (meth)acrylic group is preferred. In other words, specific monomer A is preferably a (meth)acrylic compound. Among these, the polymerizable group is more preferably a methacrylic group, as this provides a more excellent effect of the present invention.
The specific monomer A is preferably a monofunctional monomer.

The specific monomer A preferably contains at least one of an aromatic ring and an aliphatic heterocycle, from the viewpoint of achieving a glass transition temperature of a predetermined value or higher.
The aromatic ring may be a monocyclic or polycyclic ring, and the number of ring atoms is preferably 5 to 20. The aromatic ring group may have one or more (for example, 1 to 5) heteroatoms (such as oxygen atoms, sulfur atoms, and nitrogen atoms) as ring atoms.
Examples of the aromatic ring include a benzene ring, a naphthalene ring, a tolylene ring, an anthracene ring, a thiophene ring, a furan ring, a pyrrole ring, a benzothiophene ring, a benzofuran ring, a benzopyrrole ring, a triazine ring, an imidazole ring, a benzimidazole ring, a triazole ring, a thiadiazole ring, and a thiazole ring, and a benzene ring is preferred.

The aliphatic heterocycle may be monocyclic or polycyclic, and may be bridged. A bridged aliphatic heterocycle refers to a compound having a bridged structure such as norbornene.
The number of ring atoms in the aliphatic heterocycle is preferably 5 to 20. The aliphatic heterocycle contains one or more (e.g., 1 to 5) heteroatoms as ring atoms. Examples of the heteroatom include an oxygen atom, a sulfur atom, and a nitrogen atom. In addition, in the aliphatic heterocycle, at least one of the ring atoms may be substituted with a carbonyl carbon.
Examples of the aliphatic heterocycle include the aliphatic hydrocarbon rings (1) to (50) shown below, in which at least one ring member atom is substituted with a heteroatom such as an oxygen atom. In addition, at least one ring member atom in the aliphatic hydrocarbon rings (1) to (50) shown below may be substituted with a carbonyl carbon.

In particular, from the viewpoint of achieving a glass transition temperature above a predetermined value, the aliphatic heterocycle is preferably a polycyclic aliphatic heterocycle (an aliphatic heterocycle with a polycyclic structure), and more preferably a bridged one.

The specific polymer A may contain only one or more aromatic rings, only one or more aliphatic heterocycles, or one or more aromatic rings and one or more aliphatic heterocycles. When the specific polymer A contains one or more aromatic rings and one or more aliphatic heterocycles, the aromatic rings and the aliphatic heterocycles may form a polycyclic structure.
The aromatic ring and the aliphatic heterocycle may further have a substituent.

A preferred embodiment of specific polymer A is a polymerizable compound having an aliphatic heterocycle with a polycyclic structure, or a polymerizable compound having an aromatic ring.

Specific examples of the specific polymer A include compounds represented by the following general formula (A1).
General formula (A1): Y-L-Z-(R) _p
In the formula, Y represents a polymerizable group. L represents a single bond or a divalent linking group. Z represents a (p+1)-valent cyclic structural moiety containing one or more selected from aromatic rings and aliphatic heterocycles. R represents an acid-decomposable group. p represents an integer of 1 or more.

Examples of the polymerizable group represented by Y include the polymerizable groups described above. In terms of obtaining superior effects of the present invention, a maleimide group or a (meth)acrylic group is preferred, a maleimide group or a methacrylic group is more preferred, and a methacrylic group is even more preferred.
Examples of the divalent linking group represented by L include -CO-, -NR ^d -, -O-, -S-, -SO-, -SO ₂ -, alkylene groups, cycloalkylene groups, alkenylene groups, divalent aliphatic heterocyclic groups, divalent aromatic heterocyclic groups, divalent aromatic hydrocarbon ring groups, and divalent linking groups combining a plurality of these. The above-mentioned alkylene groups, cycloalkylene groups, alkenylene groups, divalent aliphatic heterocyclic groups, divalent aromatic heterocyclic groups, and divalent aromatic hydrocarbon ring groups may further have a substituent. R ^d in the above -NR ^d - represents a hydrogen atom or an organic group. The organic group is preferably an alkyl group (for example, having 1 to 6 carbon atoms).

The alkylene group may be linear or branched, and preferably has 1 to 6 carbon atoms.
The cycloalkylene group preferably has 3 to 15 carbon atoms.
The alkenylene group preferably has 2 to 6 carbon atoms.
The divalent aliphatic heterocyclic group is preferably a ring having 5 to 10 ring atoms and containing a heteroatom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom as a ring member atom. An example of the divalent aliphatic heterocyclic group is a group represented by the following formula: In the formula, each Rg independently represents a hydrogen atom or a substituent (preferably, the substituent is a hydroxyl group), and * represents a bonding position.

The divalent aromatic heterocyclic group is preferably a ring having 5 to 10 ring atoms and containing a heteroatom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom as a ring atom.
The divalent aromatic hydrocarbon ring group includes rings having 6 to 10 ring atoms.

When the divalent linking group represented by L contains a divalent aliphatic heterocyclic group, a divalent aromatic heterocyclic group, or a divalent aromatic hydrocarbon ring group, the divalent aliphatic heterocyclic group, the divalent aromatic heterocyclic group, or the divalent aromatic hydrocarbon ring group is preferably located at a position adjacent to Z shown in general formula (A1). In other words, the position adjacent to Z shown in general formula (A1) is preferably a divalent aliphatic heterocyclic group, a divalent aromatic heterocyclic group, or a divalent aromatic hydrocarbon ring group.

The divalent linking group represented by L is preferably -CO-, -NR ^d -, -O-, -S-, -SO-, -SO ₂ -, an alkylene group, a divalent aliphatic heterocyclic group, a divalent aromatic hydrocarbon ring group, or a divalent linking group formed by combining two or more of these.
Examples of the "divalent linking group formed by combining a plurality of these" include -alkylene group-O-alkylene group-phenylene group-.

Z represents a cyclic structural moiety containing at least one selected from an aromatic ring and an aliphatic heterocycle.
The aromatic ring and the aliphatic aromatic ring are as described above.
The cyclic structural moiety is a (p+1) valent group constituted by a ring which may have a substituent.
The ring may be a monocycle or a polycycle, and examples thereof include an aromatic ring, an aliphatic heterocycle, and a polycycle formed by an aromatic ring and an aliphatic heterocycle.
The cyclic structural portion may have a substituent. The substituent referred to here refers to a substituent other than the group represented by Y-L- shown in general formula (A1) and R. The substituent is not particularly limited, and examples thereof include a hydroxyl group, a phenyl group, a cyano group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, and a carboxy group. These substituents may further have a substituent.

Specific examples of the ring constituting the cyclic structural moiety represented by Z include the rings exemplified in the upper part as specific examples of the aromatic ring and the aliphatic aromatic ring, as well as the rings shown below. Note that the rings exemplified in the upper part as specific examples of the aromatic ring and the aliphatic aromatic ring, and the rings shown below, form the cyclic structural moiety represented by Z by removing p+1 hydrogen atoms possessed by the ring member atoms. That is, for example, in the case of formula (AT1-2) described later, at least p+1 of Rg, ^Rg1 , and ^Rg1 represent hydrogen atoms, and the cyclic structural moiety represented by Z is formed by removing these hydrogen atoms. In the case of formula (AT1-1) described later, p+1 hydrogen atoms are removed from hydrogen atoms that can be bonded to carbon atoms of two benzene rings shown in the formula (wherein, when n3 is not 4, the benzene ring has a hydrogen atom) and from Rg ¹ and Rg ² that represent hydrogen atoms (in other words, those of Rg ¹ and Rg ² that represent hydrogen atoms), thereby forming a cyclic structural moiety represented by Z. In the case of formula (AT1-3) described later, p+1 hydrogen atoms are removed from hydrogen atoms that can be bonded to carbon atoms of one benzene ring shown in the formula (wherein, when n3 is not 4, the benzene ring has a hydrogen atom) and from Rg, Rg ¹ , and Rg ² that represent hydrogen atoms (in other words, those of Rg, Rg ¹ , and Rg ² that represent hydrogen atoms), thereby forming a cyclic structural moiety represented by Z.
Specific examples of the ring constituting the cyclic structure moiety represented by Z are not limited to these.

Monocyclic or polycyclic 5- to 7-membered lactone rings; for example, those represented by the following formulae (LC1-1) to (LC1-21). Examples of the substituent (Rb ₂ ) include a hydroxyl group, a phenyl group, a cyano group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, and a carboxy group. n2 represents, for example, an integer of 0 to 4 (preferably an integer of 0 to 2). When n2 is 2, multiple Rb _2s may be different from each other, or multiple Rb _2s may be bonded to form a ring. Furthermore, one or more (for example, 1 to 2) methylene groups that are not adjacent to -COO- or -O- among the ring-member atoms of the lactone ring below may be replaced with a heteroatom such as -O- or -S-.

A monocyclic or polycyclic 5- to 7-membered sultone ring, for example, those represented by the following formulae (SL1-1) to (SL1-3): The substituents (Rb ₂ ) and n2 can be explained in the same way as the substituents (Rb ₂ ) and n2 in the lactone structure.
Furthermore, one or more (for example, 1 to 2) methylene groups not adjacent to —COO— or —O— among the ring member atoms of the sultone ring may be replaced with a heteroatom such as —O— or —S—.

Other examples: Examples other than the lactone ring and sultone ring described above include the following formulae (AT1-1) to (AT1-3). Rf represents a substituent, and examples thereof include the same as the substituent (Rb ₂ ) in the lactone structure. n3 represents, for example, an integer of 0 to 4 (preferably an integer of 0 to 2). When n3 is 2 or greater, the multiple Rfs may be different from each other, or the multiple Rfs may be bonded to each other to form a ring.
Rg, Rg ¹ and Rg ² each independently represent a hydrogen atom or a substituent. Examples of the substituent represented by Rg, Rg ¹ and Rg ² include the same as the substituent (Rb ₂ ) in the lactone structure.
In the following formulae (AT1-1) to (AT1-3), it is preferable that one or more (preferably two or more) of ^Rg1 represent a hydrogen atom, and that removal of this hydrogen atom forms a bond to R in general formula (A1). It is also preferable that ^Rg2 represent a hydrogen atom, and removal of this hydrogen atom forms a bond to the group represented by Y-L- in general formula (A1). The ring represented by the following general formula (AT1-1) has 9,10-dihydroanthracene as its basic skeleton.

R represents an acid-decomposable group. Examples of the acid-decomposable group represented by R include the acid-decomposable groups described above, and preferred embodiments are also the same.

p represents an integer of 1 or greater. p is preferably 2 to 6, more preferably 2 to 4, and even more preferably 2, in terms of better effects of the present invention.

Specific examples (Group A and Group B) of the specific monomer A are shown below, but the invention is not limited thereto. All of the compounds belonging to (Group A) of the specific monomer A shown below correspond to compounds having 9,10-dihydroanthracene as a basic skeleton.
(Group A)

(Group B)

<<Repeating Unit of Specific Acid-Decomposable Resin A>>
<Repeating Unit Derived from Specific Monomer A (Acid-Decomposable Repeating Unit)>
The specific acid-decomposable resin A contains a repeating unit derived from the specific monomer A as the acid-decomposable repeating unit.
The repeating unit derived from the specific monomer A may be used alone or in combination of two or more kinds.
The lower limit of the content of the repeating units derived from the specific monomer A is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 40% by mass or more, based on the total repeating units of the specific acid-decomposable resin A. The upper limit is preferably 100% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

<Other Acid-Decomposable Repeating Units>
The specific acid-decomposable resin A may contain, as the acid-decomposable repeating unit, an acid-decomposable repeating unit other than the repeating unit derived from the specific monomer A. Examples of the other acid-decomposable repeating unit include the repeating unit derived from the above-mentioned (meth)acrylic compound having an acid-decomposable group.

<Repeating Unit Having an Acid Group>
The specific acid-decomposable resin A may have a repeating unit having an acid group.
The repeating unit having an acid group is preferably a repeating unit different from the repeating units described above.
The acid group is preferably an acid group having a pKa of not more than 13. The acid dissociation constant of the acid group is preferably not more than 13, more preferably from 3 to 13, and even more preferably from 5 to 10, as described above.
When the specific acid-decomposable resin A has acid groups with a pKa of 13 or less, the content of acid groups in the specific acid-decomposable resin A is not particularly limited, but is often 0.2 to 6.0 mmol/g. Among these, 0.8 to 6.0 mmol/g is preferred, 1.2 to 5.0 mmol/g is more preferred, and 1.6 to 4.0 mmol/g is even more preferred. When the acid group content is within the above range, development proceeds well, and the formed pattern shape is excellent, and resolution is also excellent.
The acid group is preferably, for example, a carboxyl group, a hydroxyl group, an aromatic hydroxyl group (phenolic hydroxyl group), a fluorinated alcohol group (preferably a hexafluoroisopropanol group), a sulfonic acid group, a sulfonamide group, or an isopropanol group.
Furthermore, in the hexafluoroisopropanol group, one or more (preferably one or two) fluorine atoms may be substituted with a group other than a fluorine atom (such as an alkoxycarbonyl group). The thus formed —C(CF ₃ )(OH)—CF ₂ — is also preferred as the acid group. Furthermore, one or more fluorine atoms may be substituted with a group other than a fluorine atom to form a ring containing —C(CF ₃ )(OH)—CF ₂ —.
The repeating unit having an acid group may have a fluorine atom or an iodine atom.

The repeating unit having an acid group is preferably a repeating unit represented by general formula (B).

_R3 represents a hydrogen atom or an organic group which may have a fluorine atom or an iodine atom.
The organic group which may have a fluorine atom or an iodine atom is preferably a group represented by -L ₄ -R _{8. L 4} represents a single bond or an ester group. R ₈ includes an alkyl group which may have a fluorine atom or an iodine atom, a cycloalkyl group which may have a fluorine atom or an iodine atom, an aryl group which may have a fluorine atom or an iodine atom, or a group combining these.

_R4 and _R5 each independently represent a hydrogen atom, a fluorine atom, an iodine atom, or an alkyl group which may have a fluorine atom or an iodine atom.

_L2 represents a single bond, an ester group, or a divalent group formed by combining -CO-, -O-, and an alkylene group (preferably having 1 to 6 carbon atoms, which may be linear or branched, and in which _-CH2- may be substituted with a halogen atom).
_L3 represents an (n+m+1)-valent aromatic hydrocarbon ring group or an (n+m+1)-valent alicyclic hydrocarbon ring group. Examples of the aromatic hydrocarbon ring group include a benzene ring group and a naphthalene ring group. The alicyclic hydrocarbon ring group may be monocyclic or polycyclic, and examples thereof include a cycloalkyl ring group, a norbornene ring group, and an adamantane ring group.

_R6 represents a hydroxyl group or a fluorinated alcohol group. The fluorinated alcohol group is preferably a group represented by the following formula (3L).
*-L _6X -R _6X (3L)
L _6X represents a single bond or a divalent linking group. The divalent linking group is not particularly limited, and examples thereof include -CO-, -O-, -SO-, -SO ₂ -, -NR ^A -, an alkylene group (preferably having 1 to 6 carbon atoms, which may be linear or branched), and a divalent linking group combining a plurality of these. ^{R A} includes a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The alkylene group may have a substituent. Examples of the substituent include a halogen atom (preferably a fluorine atom) and a hydroxyl group. _{R 6X} represents a hexafluoroisopropanol group.
When _R6 is a hydroxyl group, _L3 is also preferably an aromatic hydrocarbon ring group having a valence of (n+m+1).

_R7 represents a halogen atom.
m represents an integer of 1 or more, preferably an integer of 1 to 3, and more preferably an integer of 1 or 2.
n represents an integer of 0 or greater than 1. n is preferably an integer of 1 to 4.
It is preferable that (n+m+1) is an integer of 1 to 5.

The repeating unit having an acid group is also preferably a repeating unit represented by formula (A2).
The repeating unit represented by formula (A2) is a repeating unit having an aromatic hydroxyl group as the acid group.

In general formula (A2), R ₁₀₁ , R ₁₀₂ , and R ₁₀₃ each independently represent a hydrogen atom, an alkyl group (which may be linear or branched, for example, having 1 to 6 carbon atoms), a cycloalkyl group (monocyclic or polycyclic, for example, having 3 to 15 ring atoms), a halogen atom, a cyano group, or an alkoxycarbonyl group (which may be linear or branched, for example, having 2 to 7 carbon atoms).

In formula (A2), L 1 _A represents a single bond or a divalent linking group.
Examples of the divalent linking group represented by L _A in general formula (A2) include -CO-, -NR-, -CO-, -O-, -S-, -SO-, -SO ₂ -, alkylene groups (preferably having 1 to 6 carbon atoms, which may be linear or branched), cycloalkylene groups (preferably having 3 to 15 carbon atoms), alkenylene groups (preferably having 2 to 6 carbon atoms), divalent aliphatic heterocyclic groups (preferably a ring having 5 to 10 ring atoms and having at least one nitrogen atom, oxygen atom, sulfur atom, or selenium atom as a ring member atom), divalent aromatic heterocyclic groups (preferably a ring having 5 to 10 ring atoms and having at least one nitrogen atom, oxygen atom, sulfur atom, or selenium atom as a ring member atom), divalent aromatic hydrocarbon ring groups (preferably a ring having 6 to 10 ring atoms), and divalent linking groups combining a plurality of these. R in the -NR- represents a hydrogen atom or an organic group. The organic group is preferably an alkyl group (for example, having 1 to 6 carbon atoms).

Ar _A represents an aromatic ring group (such as a benzene ring group).
The aromatic ring group may be monocyclic or polycyclic, and may or may not have one or more (e.g., 1 to 3) heteroatoms as ring member atoms. The number of ring member atoms of the aromatic ring group is preferably 5 to 15.

In general formula (A2), k represents an integer from 1 to 5.

However, R ₁₀₂ may be bonded to Ar 1 _A , and in that case, R ₁₀₂ represents a single bond or an alkylene group (which may be linear or branched and has, for example, 1 to 6 carbon atoms).
In this case, the aromatic ring group represented by Ar _{1 A} is bonded to the carbon atom constituting the main chain (the carbon atom to which R ₁₀₁ is bonded) via the single bond or the alkylene group.

Below are examples of repeating units having acid groups.

In the examples below, in the formula, a represents 1 or 2.

Among the repeating units listed above, the repeating units specifically described below are preferred. In the formula, R represents a hydrogen atom or a methyl group, and a represents 2 or 3.

The repeating unit having an acid group may be used alone or in combination of two or more.
The content of the repeating unit having an acid group is preferably 5 to 80 mass %, more preferably 5 to 60 mass %, still more preferably 10 to 50 mass %, and particularly preferably 15 to 50 mass %, based on the total repeating units of the specific acid-decomposable resin A.

<Repeating Unit Having a Lactone Group>
The specific acid-decomposable resin A also preferably has a repeating unit having a lactone group.
The repeating unit having a lactone group is preferably a repeating unit different from the repeating units described above.
Furthermore, the repeating unit having a lactone group may also serve as the repeating unit described above (for example, a repeating unit having an acid-decomposable group).

The lactone group may have a lactone structure. The lactone structure is preferably a 5- to 7-membered ring lactone structure. Among these, a 5- to 7-membered ring lactone structure to which another ring structure is condensed to form a bicyclo structure or a spiro structure is more preferred.
The specific acid-decomposable resin A preferably has a repeating unit having a lactone group obtained by abstracting one or more (for example, one or two) hydrogen atoms of a lactone structure represented by any one of the following formulae (LC1-1) to (LC1-21):
Alternatively, the lactone group may be directly bonded to the main chain. For example, the ring atoms of the lactone group may constitute the main chain of the specific acid-decomposable resin A.

The lactone structure may have a substituent (Rb ₂ ). Examples of the substituent (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a carboxyl group, a halogen atom, a hydroxyl group, a cyano group, a group containing an acid-decomposable group (which may be the acid-decomposable group itself), and groups consisting of combinations thereof. n2 represents an integer of 0 to 4. When n2 is 2 or greater, the multiple Rb _2s present may be different from each other, or the multiple Rb _2s present may be bonded to each other to form a ring.
Among the ring atoms of the lactone structure, one or more (for example, 1 to 2) methylene groups not adjacent to —COO— or —O— may be replaced with a heteroatom such as —O— or —S—.

Examples of repeating units having a lactone group include repeating units represented by the following general formula (AI):

In formula (AI), Rb ₀ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.
Preferred examples of the substituent that the alkyl group of Rb ₀ may have include a hydroxyl group and a halogen atom.
Examples of the halogen atom of Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom or a methyl group.
Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group combining these. Among these, a single bond or a linking group represented by -Ab ₁ -CO ₂ - is preferred. Ab ₁ represents a linear or branched alkylene group, or a monocyclic or polycyclic cycloalkylene group, and is preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group, or a norbornylene group.
V represents a group obtained by removing one hydrogen atom from a ring atom of a lactone structure represented by any one of formulae (LC1-1) to (LC1-21).

The repeating unit having a lactone group may be, for example, a repeating unit represented by general formula (AII) or (AIII).

In formulae (AII) and (AIII), each RIII independently represents a hydrogen atom or a substituent.
RIII is preferably a hydrogen atom.
In general formula (AII), ahd ₁ represents a group obtained by removing one hydrogen atom from each of adjacent ring atoms in a lactone structure represented by any one of formulae (LC1-1) to (LC1-21).
In general formula (AIII), _ahd2 represents a group obtained by removing two hydrogen atoms from one of the ring atoms of a lactone structure represented by any one of formulae (LC1-1) to (LC1-21).

Examples of repeating units having a lactone group are shown below.

When optical isomers are present in the repeating unit having a lactone group, any optical isomer may be used. Furthermore, one optical isomer may be used alone, or multiple optical isomers may be used in combination. When one optical isomer is primarily used, its optical purity (ee) is preferably 90 or higher, and more preferably 95 or higher.

The repeating unit having a lactone group may be used alone or in combination of two or more.
The content of the repeating unit having a lactone group is preferably 1 to 50 mass%, more preferably 3 to 40 mass%, still more preferably 5 to 30 mass%, and particularly preferably 5 to 20 mass%, based on the total repeating units in the specific acid-decomposable resin A.

Specific acid-decomposable resin A may also contain other repeating units. Examples of such other repeating units include the repeating units listed in paragraphs [0074] to [0079], [0090] to [0100], and [0103] to [0133] of WO 2018/193954, the repeating units listed in paragraphs [0152] to [00173] of WO 2020/004306, and repeating units having a sultone group or a carbonate group listed in paragraphs [0042] to [0059] of WO 2019/167481.

In addition to the repeating structural units described above, specific acid-decomposable resin A may have various repeating structural units for the purpose of adjusting dry etching resistance, suitability for standard developers, substrate adhesion, resist profile, resolution, heat resistance, sensitivity, etc.

The specific acid-decomposable resin A can be synthesized by a conventional method (for example, radical polymerization).
The weight-average molecular weight of the specific acid-decomposable resin A, as measured by GPC in terms of polystyrene, is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, and even more preferably 5,000 to 15,000. By adjusting the weight-average molecular weight of the specific acid-decomposable resin A to fall within the above range, deterioration in heat resistance and dry etching resistance can be further suppressed. In addition, deterioration in developability and deterioration in film-formability due to increased viscosity can be further suppressed.
The dispersity (molecular weight distribution) of the specific acid-decomposable resin A is typically 1.0 to 5.0, preferably 1.0 to 3.0, more preferably 1.2 to 3.0, and even more preferably 1.2 to 2.0. The smaller the dispersity, the better the resolution and resist shape, and further the smoother the sidewalls of the resist pattern and the better the roughness.

The specific acid-decomposable resin A may be used alone or in combination of two or more.
In the resist composition of the first embodiment, the content of the specific acid-decomposable resin A is preferably 10 to 99.9 mass %, more preferably 60 to 99.5 mass %, even more preferably 70 to 99 mass %, and particularly preferably 80 to 99 mass %, relative to the total solid content of the composition.
The term "solids" refers to components that form the resist film and does not include solvents. In addition, components that form the resist film are considered to be solids even if they are in liquid form.

[Photoacid generator]
The resist composition of the first embodiment contains a photoacid generator.
A photoacid generator is a compound that generates an acid when irradiated with actinic rays or radiation.

The photoacid generator is preferably a low molecular weight compound, and its molecular weight is preferably 3000 or less, more preferably 2000 or less, and even more preferably 1000 or less. The lower limit of the molecular weight is, for example, 100 or more.
The photoacid generator is not particularly limited, but is preferably a compound that generates an organic acid when irradiated with actinic rays or radiation (preferably electron beams or extreme ultraviolet rays) or when heated.
The organic acid is preferably at least one of sulfonic acid, bis(alkylsulfonyl)imide, and tris(alkylsulfonyl)methide, for example.

The photoacid generator may be an ionic compound or a non-ionic compound.

<Photoacid generators that are ionic compounds>
The photoacid generator that is an ionic compound may be a photoacid generator that is an onium salt, or may be a photoacid generator that is an inner salt (betaine compound).

(Photoacid generators that are onium salts)
Photoacid generators that are onium salts typically have a cationic moiety and an anionic moiety.
The photoacid generator which is an onium salt includes, for example, a compound represented by "M ^p+ _m X ^q- _n ".
In "M ^p+ _m X ^q- _n ", p, q, m, and n each independently represent an integer of 1 or more (preferably 1 to 8).
M ^p+ represents an organic cation having a charge of p. The organic cation may contain a cationic moiety as a part thereof, or may be the cationic moiety itself. Preferably, the organic cation is the cationic moiety itself.
X ^q- represents an organic anion having a charge of q. The organic anion may contain an anionic moiety as a part thereof, or may be the anionic moiety itself. The organic anion preferably contains an anionic moiety as a part thereof.
When there are a plurality of M ^p+ and X ^q− , they may be the same or different.
The value obtained by multiplying the average value of p in the multiple M ^p+s by m is the same as the value obtained by multiplying the average value of q in the multiple X ^q−s by n.
Among these, p is preferably 1.
For example, it is preferable that p, q, m, and n are all 1.
In addition, it is also preferable that p is 1, q is 2 to 8, m is the same as q, and n is 1.

Organic Cation The cationic moiety is a structural moiety containing a positively charged atom or atomic group, and is preferably, for example, a monovalent organic cation.
The organic cations are preferably each independently an organic cation represented by formula (ZaI) (cation (ZaI)) or an organic cation represented by formula (ZaII) (cation (ZaII)).

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 group represented by R ²⁰¹ , R ²⁰² , and R ²⁰³ is usually 1 to 30, and preferably 1 to 20. Two of R ²⁰¹ to R ²⁰³ may be bonded 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 groups formed by bonding two of R ²⁰¹ to R ²⁰³ include alkylene groups (e.g., butylene and pentylene groups) and -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -.

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

First, the cation (ZaI-1) will be described.
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 aryl groups, or some of R ₂₀₁ to R ₂₀₃ may be aryl groups, with the remainder being alkyl groups or cycloalkyl groups.
Alternatively, 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, which may contain an oxygen atom, a sulfur atom, an ester group, an amide group, or a carbonyl group in the ring.
Examples of groups formed by bonding two of R ²⁰¹ to R ²⁰³ include an alkylene group AL, -aromatic ring group-alkylene group AL-aromatic ring group-, -aromatic ring group-aromatic ring group-, and -aromatic ring group-O-aromatic ring group-. The alkylene group AL is a linear or branched alkylene group. One or more methylene groups constituting the alkylene group AL may be substituted with an oxygen atom, a sulfur atom, an ester group, an amide group, and/or a carbonyl group. Examples of the alkylene group AL include a butylene group, a pentylene group, and -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -.
Examples of arylsulfonium cations include triarylsulfonium cations, diarylalkylsulfonium cations, aryldialkylsulfonium cations, diarylcycloalkylsulfonium cations, and aryldicycloalkylsulfonium cations.
Two of the aryl groups in the triarylsulfonium cation, diarylalkylsulfonium cation, and diarylcycloalkylsulfonium cation may be bonded via a single bond or a divalent linking group (such as —O—, —S—, an alkylene group, or a group formed by a combination thereof).

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

The substituents that the aryl group, alkyl group, and cycloalkyl group of R ²⁰¹ to R ²⁰³ may have are each independently preferably an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms), an alkoxy group (for example, 1 to 15 carbon atoms), a cycloalkylalkoxy group (for example, 1 to 15 carbon atoms), a cycloalkylsulfonyl group (for example, 1 to 15 carbon atoms), a halogen atom (for example, fluorine, iodine), a hydroxyl group, a carboxyl group, a group having an ester group, a group having a sulfinyl group, a group having a sulfonyl group, an alkylthio group, a phenylthio group, etc.
The above-mentioned substituent may further have a substituent if possible. For example, it is also preferred that the above-mentioned alkyl group has a halogen atom as a substituent to form a halogenated alkyl group such as a trifluoromethyl group.
It is also preferred that the above substituents are combined in any desired manner to form an acid-decomposable group.
The acid-decomposable group is intended to be a group that decomposes under the action of an acid to generate a polar group, and preferably has a structure in which the polar group is protected with a leaving group that is released under the action of an acid. The polar group and leaving group are as described above.

Next, the cation (ZaI-3b) will be described.
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, a hydroxyl group, a nitro group, an alkylthio group, or an 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.
It is also preferred that the substituents of R _1c to R _7c and R _x and R _y each independently form an acid-decomposable group through any combination of the substituents.

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, and each of these rings may independently contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond.
Examples of the ring include aromatic or non-aromatic hydrocarbon rings, aromatic or non-aromatic heterocycles, and polycyclic fused rings formed by combining two or more of these rings. Examples of the ring include 3- to 10-membered rings, preferably 4- to 8-membered rings, and more preferably 5- or 6-membered rings.

Examples of groups formed by combining 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 butylene and pentylene, in which a methylene group may be substituted with a heteroatom such as an oxygen atom.
The groups formed by combining R _5c and R _6c , and R _5c and R _x are preferably a single bond or an alkylene group, such as a methylene group or an ethylene group.

R _1c to R _5c , R _6c , R _7c , R _x , R _y , _and the rings formed by combining 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 each have a substituent.

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

In formula (ZaI-4b),
l represents an integer of 0 to 2.
r represents an integer of 0 to 8;
_R13 represents a hydrogen atom, a halogen atom (e.g., a fluorine atom, an iodine atom, etc.), a hydroxyl group, an alkyl group, a halogenated alkyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or a group having a cycloalkyl group (which may be a cycloalkyl group itself or a group containing a cycloalkyl group as a part). These groups may have a substituent.
R ₁₄ represents a hydroxyl group, a halogen atom (e.g., 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 group having a cycloalkyl group (which may be a cycloalkyl group itself or a group containing a cycloalkyl group as a part). These groups may have a substituent. When multiple R _14s are present, each independently represents the above group such as a hydroxyl group.
Each R ₁₅ independently represents an alkyl group, a cycloalkyl group, or a naphthyl group. Two R ₁₅ may be bonded to each other to form a ring. When two R ₁₅ are bonded to 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, it is preferred that two R ₁₅ 's are alkylene groups and bond to each other to form a ring structure. The alkyl group, the cycloalkyl group, the naphthyl group, and the ring formed by bonding two R ₁₅ 's to each other may have a substituent.

In formula (ZaI-4b), the alkyl groups of R ₁₃ , R ₁₄ , and R ₁₅ are linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 10. The alkyl group is more preferably a methyl group, an ethyl group, an n-butyl group, a t-butyl group, or the like.
It is also preferred that the substituents of R ₁₃ to R ₁₅ and R _x and R _y each independently form an acid-decomposable group by any combination of the substituents.

Next, formula (ZaII) will be described.
In formula (ZaII), R ²⁰⁴ and R ²⁰⁵ each independently represent an aryl group, an alkyl group, or a cycloalkyl group.
The aryl group of R ²⁰⁴ and R ²⁰⁵ is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group of R ²⁰⁴ and R ²⁰⁵ may be an aryl group having a heterocycle containing 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 are preferably a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (e.g., a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group), or a cycloalkyl group having 3 to 10 carbon atoms (e.g., a cyclopentyl group, a cyclohexyl group, or a norbornyl group).

The aryl group, alkyl group, and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ may each independently have a substituent. Examples of the substituent that the aryl group, alkyl group, and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ may have include an alkyl group (e.g., having 1 to 15 carbon atoms), a cycloalkyl group (e.g., having 3 to 15 carbon atoms), an aryl group (e.g., having 6 to 15 carbon atoms), an alkoxy group (e.g., having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group. It is also preferable that the substituents of R ²⁰⁴ and R ²⁰⁵ each independently form an acid-decomposable group by any combination of substituents.

Organic Anions Examples of organic anions include phenolic hydroxyl anions, sulfonate anions (aliphatic sulfonate anions, aromatic sulfonate anions, camphorsulfonate anions, etc.), carboxylate anions (aliphatic carboxylate anions, aromatic carboxylate anions, aralkyl carboxylate anions, formate anions, hydrogen carbonate anions, etc.), carbonylsulfonylimide anions, bis(sulfonyl)imide anions (bis(alkylsulfonyl)imide anions, etc.), bis(carbonyl)imide anions, and tris(alkylsulfonyl)methide anions.

The aliphatic moiety in the aliphatic sulfonate anion and the aliphatic carboxylate anion may be an alkyl group or a cycloalkyl group, and is preferably a linear or branched alkyl group having 1 to 30 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms.
The alkyl group may be, for example, a fluoroalkyl group (which may or may not have a substituent other than a fluorine atom; it may also be a perfluoroalkyl group).
The cycloalkyl group may be monocyclic or polycyclic, and one or more (preferably 1 to 2) of the -CH ₂ - groups constituting the ring structure may be replaced by a heteroatom (such as -O- or -S-), -SO ₂ -, -SO ₃ -, an ester group, or a carbonyl group.

As the aryl group in the aromatic sulfonate anion and aromatic carboxylate anion, an aryl group having 6 to 14 carbon atoms is preferred, such as a phenyl group, a tolyl group, and a naphthyl group.

The alkyl groups, cycloalkyl groups, and aryl groups listed above may have a substituent. The substituent is not particularly limited, but specific examples include a nitro group, a halogen atom such as a fluorine atom or a chlorine atom, a carboxy group, a hydroxyl group, an amino group, a cyano group, an alkoxy group (preferably having 1 to 15 carbon atoms), an alkyl group (preferably having 1 to 10 carbon atoms), a cycloalkyl group (preferably having 3 to 15 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably having 2 to 7 carbon atoms), an acyl group (preferably having 2 to 12 carbon atoms), an alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), an alkylthio group (preferably having 1 to 15 carbon atoms), an alkylsulfonyl group (preferably having 1 to 15 carbon atoms), an alkyliminosulfonyl group (preferably having 1 to 15 carbon atoms), and an aryloxysulfonyl group (preferably having 6 to 20 carbon atoms).

As the aralkyl group in the aralkyl carboxylic acid anion, an aralkyl group having 7 to 14 carbon atoms is preferred, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylbutyl group.

Examples of sulfonylimide anions include saccharin anions.

The alkyl group in the bis(alkylsulfonyl)imide anion and the tris(alkylsulfonyl)methide anion is preferably an alkyl group having 1 to 5 carbon atoms. Substituents on these alkyl groups include a halogen atom, an alkyl group substituted with a halogen atom, an alkoxy group, an alkylthio group, an alkyloxysulfonyl group, an aryloxysulfonyl group, and a cycloalkylaryloxysulfonyl group, and a fluorine atom or an alkyl group substituted with a fluorine atom is preferred.
In addition, the alkyl groups in the bis(alkylsulfonyl)imide anion may be bonded to each other to form a ring structure.

Preferred organic anions include aliphatic sulfonate anions in which at least the α-position of the sulfonic acid is substituted with a fluorine atom (such as an aliphatic sulfonate anion with one or two fluorine atoms substituted at the α-position), aliphatic sulfonate anions in which the α-position of the sulfonic acid is not substituted with a fluorine atom (such as an aliphatic sulfonate anion in which no fluorine atom is substituted at the α-position and 0 to 3 fluorine atoms or perfluoroalkyl groups are substituted at the β-position), aromatic sulfonate anions substituted with a fluorine atom or a group containing a fluorine atom, bis(alkylsulfonyl)imide anions in which the alkyl group is substituted with a fluorine atom, and tris(alkylsulfonyl)methide anions in which the alkyl group is substituted with a fluorine atom.

Also preferred as organic anions are anions represented by the following formula (AN):

In formula (AN), o represents an integer from 0 to 5. p represents an integer from 0 to 10. q represents an integer from 0 to 10.

In formula (AN), AX represents —SO ₃ ^— or —COO ^— .

In formula (AN), Xf represents a fluorine atom or an alkyl group substituted with at least one fluorine atom. The number of carbon atoms in this alkyl group is preferably 1 to 10, more preferably 1 to 4. Furthermore, the alkyl group substituted with at least one fluorine atom is preferably a perfluoroalkyl group.
Xf is preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms, more preferably a fluorine atom or CF _3. In particular, it is even more preferable that both Xf are fluorine atoms.

In formula (AN), _R4 and _R5 each independently represent a hydrogen atom, a fluorine atom, _an alkyl group, or an alkyl group substituted with at least one fluorine atom. When a plurality _{of R4s} and _R5s are present, they may be the same or different.
The alkyl group represented by R ₄ and R ₅ may have a substituent other than a fluorine atom, and preferably has 1 to 4 carbon atoms.
Specific examples and preferred embodiments of the alkyl group substituted with at least one fluorine atom are the same as the specific examples and preferred embodiments of Xf.
_R4 and _R5 are preferably hydrogen atoms.
It is also preferred that one of R ₄ and R ₅ bonded to the same carbon atom is a hydrogen atom, and the other is a fluorine atom or an alkyl group substituted with at least one fluorine atom. In particular, it is also preferred that in the -C(R ₄ )(R ₅ )- located first and/or second closest to AX, one of R ₄ and R ₅ bonded to the same carbon atom is a hydrogen atom, and the other is a fluorine atom or an alkyl group substituted with at least one fluorine atom. It is also preferred that in the -C(R ₄ )(R ₅ )- located first and/or second closest to AX, R ₄ and R ₅ are each independently a hydrogen atom or an alkyl group (which may have a substituent other than a fluorine atom).

In formula (AN), L represents a divalent linking group. When a plurality of L's are present, they may be the same or different.
Examples of the divalent linking group include -O-CO-O-, -COO-, -OCO-, -CONH-, -NHCO-, -CO-, -O-, -S-, -SO-, -SO ₂ -, alkylene groups (preferably having 1 to 6 carbon atoms), cycloalkylene groups (preferably having 3 to 15 carbon atoms), alkenylene groups (preferably having 2 to 6 carbon atoms), and divalent linking groups formed by combining a plurality of these groups. Among these, —O—CO—O—, —COO—, —OCO—, —CONH—, —NHCO—, —CO—, —O—, —SO ₂ —, —O—CO—O-alkylene group-, —alkylene group-O—CO—O—, —COO-alkylene group-, —OCO-alkylene group-, —CONH-alkylene group-, or —NHCO-alkylene group- are preferred, and —O—CO—O—, —O—CO—O-alkylene group-, —alkylene group-O—CO—O—, —COO—, —OCO—, —CONH—, —SO ₂ —, —COO-alkylene group-, or —OCO-alkylene group- are more preferred.

In formula (AN), W represents an organic group containing a cyclic structure, and is preferably a cyclic organic group.
Examples of the cyclic organic group include an alicyclic group, an aryl group, and a heterocyclic group.
The alicyclic group may be monocyclic or polycyclic. Examples of monocyclic alicyclic groups include monocyclic cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of polycyclic alicyclic groups include polycyclic cycloalkyl groups such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group. Among these, alicyclic groups having a bulky structure with 7 or more carbon atoms, such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group, are preferred.

The aryl group may be monocyclic or polycyclic, and examples of the aryl group include a phenyl group, a naphthyl group, a phenanthryl group, and an anthryl group.
The heterocyclic group may be monocyclic or polycyclic. The heterocyclic group may or may not have aromaticity. Examples of heterocyclic rings having aromaticity include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, and a pyridine ring. Examples of heterocyclic rings having no aromaticity include a tetrahydropyran ring, a lactone ring, a sultone ring, and a decahydroisoquinoline ring. As the heterocyclic ring in the heterocyclic group, a furan ring, a thiophene ring, a pyridine ring, or a decahydroisoquinoline ring is particularly preferred.

The cyclic organic group may have a substituent. Examples of the substituent include an alkyl group (which may be linear or branched, and preferably has 1 to 12 carbon atoms), a cycloalkyl group (which may be monocyclic, polycyclic, or spirocyclic, and preferably has 3 to 20 carbon atoms), an aryl group (which preferably has 6 to 14 carbon atoms), a hydroxyl group, an alkoxy group, an ester group, an amide group, a urethane group, a ureido group, a thioether group, a sulfonamide group, and a sulfonate ester group. The carbon atom constituting the cyclic organic group (the carbon atom that contributes to ring formation) may be a carbonyl carbon.

The anion represented by formula (AN) is preferably AX-CF ₂ -CH ₂ -OCO-(L)q'-W, AX-CF ₂ -CHF-CH ₂ -OCO-(L)q'-W, AX-CF ₂ -COO-(L)q'-W, AX-CF ₂ -CF ₂ -CH ₂ -CH ₂ -(L)q-W, or AX-CF ₂ -CH(CF ₃ )-OCO-(L)q'-W. Here, AX, L, q, and W are the same as those in formula (AN). q' represents an integer of 0 to 10.

(Photoacid generator that is an inner salt)
The photoacid generator that is an inner salt preferably has a sulfonate anion or a carboxylate anion (preferably an aromatic sulfonic acid or aromatic carboxylate anion), and further preferably has a sulfonium cation or an iodine cation.
Examples of photoacid generators that are inner salts include compound (ZbI) and compound (ZbII).
The compound (ZbI) is a compound represented by a general formula newly specifying that one of R ²⁰¹ to R ²⁰³ in the above general formula (ZaI) is an aryl group having a group containing —SO ₃ ^— or —COO ^— as a substituent.
The compound (ZbII) is a compound represented by a general formula newly specifying that one of R ²⁰⁴ and R ²⁰⁵ in the above general formula (ZaII) is an aryl group having a group containing —SO ₃ ^— or —COO ^— as a substituent.
In the compound (ZbI) and the compound (ZbII), examples of the group containing —SO ₃ ^— or —COO ^— include a group obtained by removing W from the organic anion represented by formula (AN) shown in the description of the organic anion (a group represented by “AX—[C(Xf)(Xf)] _o- [C(R ₄ )(R ₅ )] _p- (L) _q- ”).

Examples of photoacid generators that are inner salts are given below.
In the photoacid generators below, the numerical values shown near the sites where the hydrogen atoms of the acid groups are substituted with cations (anionic functional groups) indicate the pKa of the acid groups assuming that the hydrogen atoms are not substituted with cations.
In other words, the pKa values shown below are the pKa values of the acid group (the group formed by bonding an anionic functional group to a hydrogen atom) in a compound (acid) formed by assuming that the anionic functional group of the intramolecular salt is bonded to a hydrogen atom.

For photoacid generators, paragraphs [0368] to [0377] of JP 2014-41328 A and paragraphs [0240] to [0262] of JP 2013-228681 A (corresponding paragraph [0339] of U.S. Patent Application Publication No. 2015/004533) may be cited, the contents of which are incorporated herein by reference.

The following compounds can also be used as photoacid generators.

The photoacid generator may be used alone or in combination of two or more.
In the resist composition of the first embodiment, the content of the photoacid generator is preferably 0.5 to 40 mass %, more preferably 0.5 to 30 mass %, and even more preferably 1 to 30 mass %, relative to the total solid content of the resist composition.

[Hydrophobic resin]
The resist composition of the first embodiment may contain, in addition to the specific acid-decomposable resin A, a hydrophobic resin different from the specific acid-decomposable resin A.
The hydrophobic resin is preferably designed to be unevenly distributed on the surface of the resist film, but unlike surfactants, it does not necessarily have to have a hydrophilic group in its molecule, and it does not necessarily have to contribute to uniform mixing of polar and non-polar substances.
The effects of adding a hydrophobic resin include control of the static and dynamic contact angle of the resist film surface with water, and suppression of outgassing.

From the viewpoint of uneven distribution on the surface layer of the film, the hydrophobic resin preferably has one or more of "fluorine atoms", "silicon atoms", and " _CH3 partial structures contained in the side chain portion of the resin", and more preferably has two or more of them. In addition, the hydrophobic resin preferably has a hydrocarbon group having 5 or more carbon atoms. These groups may be contained in the main chain of the resin or may be substituted on the side chain.
Examples of hydrophobic resins include the compounds described in paragraphs [0275] to [0279] of WO 2020/004306.

When the resist composition of the first embodiment contains a hydrophobic resin, the content of the hydrophobic resin is preferably 0.01 to 20 mass% relative to the total solid content of the resist composition, more preferably 0.1 to 15 mass%, even more preferably 0.1 to 10 mass%, and particularly preferably 0.1 to 5.0 mass%.

[Surfactant]
The resist composition of the first embodiment may contain a surfactant. When a surfactant is contained, a pattern with superior adhesion and fewer development defects can be formed.
The surfactant is preferably a fluorine-based and/or silicon-based surfactant.
As the fluorine-based and/or silicone-based surfactant, for example, the surfactants disclosed in paragraphs [0218] and [0219] of WO 2018/19395 can be used.
When the resist composition of the first embodiment contains a surfactant, the content thereof is preferably from 0.0001 to 2 mass %, and more preferably from 0.0005 to 1 mass %, relative to the total solid content of the composition.
The surfactant may be used alone or in combination of two or more. When two or more surfactants are used, the total content thereof is preferably within the above-mentioned preferred content range.

〔solvent〕
The resist composition of the first embodiment may contain a solvent.
The solvent preferably contains (M1) a propylene glycol monoalkyl ether carboxylate and (M2) at least one selected from the group consisting of a propylene glycol monoalkyl ether, a lactate ester, an acetate ester, an alkoxypropionate ester, a chain ketone, a cyclic ketone, a lactone, and an alkylene carbonate. Note that this solvent may further contain components other than the components (M1) and (M2).

The present inventors have found that the use of such a solvent in combination with the above-mentioned resin improves the coatability of the composition and enables the formation of a pattern with fewer development defects. Although the reason for this is not entirely clear, the present inventors believe that this is due to the fact that these solvents have a good balance of the solubility, boiling point, and viscosity of the above-mentioned resin, making it possible to suppress unevenness in the film thickness of the composition and the occurrence of precipitates during spin coating.
Details of the components (M1) and (M2) are described in paragraphs [0218] to [0226] of WO 2020/004306.

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

The solvent may be used alone or in combination of two or more.
The content of the solvent in the resist composition of the first embodiment is preferably set so that the solids concentration is 30% by mass or less, more preferably 10% by mass or less, and even more preferably 2% by mass or less. The lower limit is preferably set so that it is 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more.
This further improves the coatability of the resist composition.
In other words, the content of the solvent in the resist composition of the first embodiment is preferably from 70 to 99.95 mass %, more preferably from 90 to 99.9 mass %, and even more preferably from 98 to 99.5 mass %, relative to the total mass of the resist composition.

[Other additives]
The resist composition of the first embodiment may further contain an acid diffusion controller, a dissolution inhibiting compound, a dye, a plasticizer, a photosensitizer, a light absorber, and/or a compound that promotes solubility in a developer (an alicyclic or aliphatic compound containing a carboxylic acid group).

The resist composition of the first embodiment may further contain a dissolution inhibiting compound. Here, a "dissolution inhibiting compound" is a compound with a molecular weight of 3000 or less that decomposes under the action of acid and reduces its solubility in an organic developer.

The resist composition of the first embodiment is also suitable for use as a photosensitive composition for EUV exposure or a photosensitive composition for electron beam exposure.

EUV light and electron beams are significantly affected by "photon shot noise," which is the stochastic variation in the number of photons, and are prone to causing deterioration of LER and bridge defects. One way to reduce photon shot noise is to increase the exposure dose and the number of incident photons, but this tends to be a trade-off with the demand for higher sensitivity.
When the value A calculated by the following formula (1) is high, the resist film formed from the resist composition has high absorption efficiency for EUV and electron beams, which is effective in reducing photon shot noise. The value A represents the absorption efficiency of EUV and electron beams by mass proportion of the resist film.
Formula (1): A = ([H] x 0.04 + [C] x 1.0 + [N] x 2.1 + [O] x 3.6 + [F] x 5.6 + [S] x 1.5 + [I] x 39.5) / ([H] x 1 + [C] x 12 + [N] x 14 + [O] x 16 + [F] x 19 + [S] x 32 + [I] x 127)
The value A is preferably 0.120 or more. Although there is no particular upper limit, if the value A is too large, the EUV and electron beam transmittance of the resist film decreases, the optical image profile in the resist film deteriorates, and as a result, it becomes difficult to obtain a good pattern shape. Therefore, the value A is preferably 0.240 or less, and more preferably 0.220 or less.

In formula (1), [H] represents the molar ratio of hydrogen atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition, [C] represents the molar ratio of carbon atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition, [N] represents the molar ratio of nitrogen atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition, and [O] represents the molar ratio of nitrogen atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition. [F] represents the molar ratio of oxygen atoms derived from all solids to all atoms in all solids, [F] represents the molar ratio of fluorine atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition, [S] represents the molar ratio of sulfur atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition, and [I] represents the molar ratio of iodine atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition.
For example, when a resist composition contains a specific acid-decomposable resin A, a photoacid generator, and a solvent, the specific acid-decomposable resin A and the photoacid generator correspond to the solid content. In other words, the total atoms of the total solid content correspond to the sum of all atoms derived from the specific acid-decomposable resin A and all atoms derived from the photoacid generator. For example, [H] represents the molar ratio of hydrogen atoms derived from all solid content to all atoms of the total solid content, and based on the above example, [H] represents the molar ratio of the sum of hydrogen atoms derived from the resin and the photoacid generator to the sum of all atoms derived from the specific acid-decomposable resin A and all atoms derived from the photoacid generator.

The A value can be calculated by calculating the atomic ratio of the components contained when the structure and content of all solid components in the resist composition are known. Even if the components are unknown, the atomic ratio of the components can be calculated by analytical methods such as elemental analysis of the resist film obtained by evaporating the solvent components of the resist composition.

[Resist film and pattern forming method]
The procedure for the pattern formation method using the resist composition of the first embodiment is not particularly limited, but it is preferable that the method include the following steps.
Step 1: Forming a resist film on a substrate using the resist composition of the first embodiment. Step 2: Exposing the resist film to light. Step 3: Developing the exposed resist film using a developer. The procedures for each of the above steps will be described in detail below.

<Step 1: Resist film forming step>
Step 1 is a step of forming a resist film on a substrate using the resist composition of the first embodiment.
The resist composition of the first embodiment is defined as above.

An example of a method for forming a resist film on a substrate using the resist composition of the first embodiment is a method in which the resist composition of the first embodiment is applied onto a substrate.
Before application, the resist composition of the first embodiment is preferably filtered as needed. 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. The filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

The resist composition of the first embodiment can be applied to a substrate (e.g., silicon, silicon dioxide-coated) such as those used in the manufacture of integrated circuit devices by a suitable application method such as a spinner or coater. Spin application using a spinner is preferred. The rotation speed during spin application using a spinner is preferably 1000 to 3000 rpm.
After coating the resist composition of the first embodiment, the substrate may be dried to form a resist film. If necessary, various types of undercoat films (inorganic films, organic films, anti-reflective films) may be formed below the resist film.

Drying methods include, for example, heating. Heating can be carried out using means provided in a typical 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, and even more preferably 80 to 130°C. The heating time is preferably 30 to 1,000 seconds, more preferably 60 to 800 seconds, and even more preferably 60 to 600 seconds.

There are no particular restrictions on the thickness of the resist film, but a thickness of 10 to 120 nm is preferred, as this allows for the formation of finer patterns with higher precision. In particular, when EUV exposure or electron beam exposure is used, the thickness of the resist film is more preferably 10 to 65 nm, and even more preferably 15 to 50 nm.

A top coat may be formed on the resist film using a top coat composition.
It is preferable that 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. For example, a top coat can be formed based on the description in paragraphs [0072] to [0082] of JP2014-059543A.
For example, it is preferable to form a top coat containing a basic compound such as that described in JP-A-2013-61648 on the resist film.
The top coat also preferably 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.
The exposure method may be a method in which the formed resist film is irradiated with actinic rays or radiation through a predetermined mask.
Examples of actinic rays or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, and electron beams, preferably far ultraviolet light having a wavelength of 250 nm or less, more preferably 220 nm or less, and particularly preferably 1 to 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.
Of these, the actinic rays or radiation used for exposure are preferably EUV or electron beams.

After exposure, it is preferable to bake (heat) the film before development, as this promotes the reaction of the exposed areas and improves the sensitivity and pattern shape.
The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, and even more preferably 80 to 130°C.
The heating time is preferably from 10 to 1,000 seconds, more preferably from 10 to 180 seconds, and even more preferably from 30 to 120 seconds.
Heating can be carried out by means provided in a normal exposure machine and/or developing machine, and may also be carried out using a hot plate or the like.
This step is also called post-exposure bake (PEB).

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

Examples of the development method include a method of immersing a substrate in a tank filled with a developer for a certain period of time (dip method), a method of piling up a developer on the surface of the substrate by surface tension and leaving it to stand for a certain period of time to develop (puddle method), a method of spraying the developer onto the surface of the substrate (spray method), and a method of continuously discharging the developer while scanning a developer discharge nozzle at a constant speed onto a substrate that is rotating at a constant speed (dynamic dispense method).
After the development step, a step of stopping the development while replacing the solvent with another solvent may be carried out.
The development time is not particularly limited as long as it is long enough to dissolve the resin in the unexposed areas, and is preferably from 10 to 300 seconds, more preferably from 20 to 120 seconds.
The temperature of the developer is preferably from 0 to 50°C, more preferably from 15 to 35°C.

The alkaline developer is preferably an aqueous alkaline solution containing an alkali. The type of alkaline solution is not particularly limited, but examples include aqueous alkaline solutions containing quaternary ammonium salts such as tetramethylammonium hydroxide, inorganic alkalis, primary amines, secondary amines, tertiary amines, alcohol amines, or cyclic amines. Of these, an aqueous alkaline developer containing a quaternary ammonium salt such as tetramethylammonium hydroxide (TMAH) is preferred. Appropriate amounts of alcohols, surfactants, etc. may be added to the alkaline developer. The alkaline concentration of the alkaline developer is typically 0.1 to 20% by weight. The pH of the alkaline developer is typically 10.0 to 15.0. The water content of the alkaline developer is preferably 51 to 99.95% by weight.

The organic developer is preferably a developer containing at least one organic solvent selected from the group consisting of ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents.

The developer as a whole preferably has a water content of less than 50% by mass, more preferably less than 20% by mass, and even more preferably less than 10% by mass, and particularly preferably contains substantially no water.
The content of the organic solvent in the organic developer is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, and particularly preferably 95 to 100% by mass, based on the total amount of the developer.

<Other processes>
The pattern forming method preferably includes, after step 3, a step of cleaning with a rinse liquid.

The rinse liquid used in the rinse step after the development step using an alkaline developer is, for example, pure water, to which an appropriate amount of surfactant may be added.
A suitable amount of a surfactant may be added to the rinse solution.

There are no particular restrictions on the rinse solution used in the rinse step following the development step using an organic developer, as long as it does not dissolve the pattern, and solutions containing common organic solvents can be used. It is preferable to use a rinse solution containing at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents.

The method of the rinsing step is not particularly limited, and examples thereof include a method of continuously discharging a rinsing liquid onto a substrate rotating at a constant speed (spin coating method), a method of immersing a substrate in a tank filled with a rinsing liquid for a certain period of time (dipping method), and a method of spraying a rinsing liquid onto the surface of the substrate (spray method).
Furthermore, the pattern formation method using the resist composition of the first embodiment may include a heating step (post-bake) after the rinsing step. This step removes the developer and rinsing solution remaining between and within the pattern due to baking. This step also has the effect of annealing the resist pattern and improving the surface roughness of the pattern. The heating step after the rinsing step is typically performed at 40 to 250°C (preferably 90 to 200°C) for typically 10 seconds to 3 minutes (preferably 30 to 120 seconds).

Alternatively, the substrate may be etched using the formed pattern as a mask. That is, the substrate (or the underlying film and the substrate) may be processed using the pattern formed in step 3 as a mask to form a pattern on the substrate.
The method for processing the substrate (or the underlayer film and the substrate) is not particularly limited, but a preferred method is to form a pattern on the substrate by dry etching the substrate (or the underlayer film and the substrate) using the pattern formed in step 3 as a mask. The dry etching is preferably oxygen plasma etching.

The resist composition of the first embodiment and the various materials used in the pattern formation method using the resist composition of the first embodiment (e.g., solvents, developers, rinse solutions, anti-reflective coating compositions, top coat compositions, etc.) preferably do not contain impurities such as metals. The content of impurities contained in these materials is preferably 1 ppm by mass or less, more preferably 10 ppb by mass or less, even more preferably 100 ppt by mass or less, particularly preferably 10 ppt by mass or less, and most preferably 1 ppt by mass or less. 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, W, and Zn.

One method for removing impurities such as metals from various materials is filtration using a filter. Details of filtration using a filter are described in paragraph [0321] of WO 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 the raw materials for the various materials, filtering the raw materials for the various materials, and performing distillation under conditions that minimize contamination as much as possible, such as by lining the inside of the equipment with Teflon (registered trademark).

In addition to filtration, impurities may be removed using an adsorbent, or a combination of filtration and an adsorbent may be used. Known adsorbents can be used as adsorbents, including inorganic adsorbents such as silica gel and zeolite, and organic adsorbents such as activated carbon. To reduce the metal and other impurities contained in the various materials listed above, it is necessary to prevent the incorporation of metal impurities 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 solution used to clean the manufacturing equipment. The content of metal components contained in the used cleaning solution is preferably 100 parts per trillion (ppt) by mass or less, more preferably 10 ppt by mass or less, and even more preferably 1 ppt by mass or less.

An organic processing liquid such as a rinse liquid may contain a conductive compound to prevent breakdown of chemical liquid piping and various parts (filters, O-rings, tubes, etc.) due to static charging and subsequent static discharge. The conductive compound is not particularly limited, but examples include methanol. 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.
For example, various pipes coated with SUS (stainless steel), or antistatically treated polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.) can be used as the chemical liquid pipe. Similarly, antistatically treated polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.) can be used for the filter and O-ring.

[Second embodiment of actinic ray-sensitive or radiation-sensitive resin composition]
The actinic ray-sensitive or radiation-sensitive resin composition of the present invention (hereinafter also referred to as the “resist composition of the second embodiment”) contains a resin (hereinafter also referred to as the “specific acid-decomposable resin B”) having a repeating unit derived from a polymerizable compound represented by general formula (1) described below (hereinafter also referred to as the “specific monomer B”), and a photoacid generator.

Although the mechanism of action of the resist composition of the second embodiment is not clear, the inventors of the present invention speculate as follows.
The specific acid-decomposable resin B contained in the resist composition of the second embodiment has a repeating unit derived from the specific monomer B. The specific monomer B has a predetermined polycyclic structure, which results in a high glass transition temperature. Therefore, the resist composition of the second embodiment containing the specific acid-decomposable resin B can form a pattern with high film strength. As a result, it is believed that the resist composition of the second embodiment has high resolution (in other words, a small limiting resolution (nm)). Furthermore, because the specific monomer B has an acid-decomposable group at a predetermined position, a pattern formed using the resist composition of the second embodiment containing the specific acid-decomposable resin B can exhibit excellent dissolution contrast. As a result, it is believed that the pattern formed using the resist composition of the second embodiment has excellent LWR performance. In other words, it is presumed that due to the structure of the specific monomer B, the resist composition of the second embodiment has excellent high resolution, and the formed pattern has excellent LWR performance.
Hereinafter, a resist composition that has higher resolution and/or a pattern formed using the resist composition that has better LWR performance may also be referred to as "the effects of the present invention being better."

The resist composition of the second embodiment will be described in detail below.
The resist composition of the second embodiment may be a positive resist composition or a negative resist composition. Furthermore, it may be a resist composition for alkali development or a resist composition for organic solvent development.
The resist composition of the second embodiment is typically a chemically amplified resist composition.
The resist composition of the second embodiment has the same configuration as the resist composition of the first embodiment except for using the specific acid-decomposable resin B instead of the specific acid-decomposable resin A, and the preferred aspects thereof are also the same.
Furthermore, the method for forming a resist film and a pattern using the resist composition of the second embodiment has the same configuration as the method for forming a resist film and a pattern using the resist composition of the first embodiment, except for using the resist composition of the second embodiment instead of the resist composition of the first embodiment, and the preferred aspects are also the same.

[Specified acid-decomposable resin B]
The resist composition of the second embodiment contains a resin (specific acid-decomposable resin B) having a repeating unit derived from a polymerizable compound (specific monomer B) represented by the following general formula (1).
The specific acid-decomposable resin B is a resin that decomposes under the action of an acid and has an increased polarity.
That is, in the pattern formation method using the resist composition of the second embodiment, typically, when an alkaline developer is used as the developer, a positive pattern is preferably formed, and when an organic developer is used as the developer, a negative pattern is preferably formed.
The specific monomer B will be described below. The specific acid-decomposable resin B has the same configuration as the specific acid-decomposable resin A except that it contains a repeating unit derived from the specific monomer B instead of the repeating unit derived from the specific monomer A, and the preferred embodiments are also the same. Therefore, in the following description, only the specific monomer B will be described.

The specific monomer B will be described below.
The specific monomer B is a polymerizable compound represented by the following general formula (1).

In the formula, L ¹ represents —CR ³ ═CR ⁴ — or —CR ⁵ R ⁶ —CR ⁷ R ⁸ —.
X ¹ represents —O—, —CR ⁹ R ¹⁰ —, or ═CR ¹¹ —.
X ² represents —O—, —CO—, —CR ¹² R ¹³ — or ═CR ¹⁴ —.
The bond between ^X1 and ^X2 , represented by a solid line and a dotted line, represents a single bond or a double bond. However, when the bond between ^X1 and ^X2 represents a double bond, ^X1 represents =CR ¹¹ -, and ^X2 represents =CR ¹⁴ -. Furthermore, when the bond between ^X1 and ^X2 represents a single bond, ^X1 represents -O- or -CR ⁹ R ¹⁰ -, and ^X2 represents -O-, -CO-, or -CR ¹² R ¹³ -.
R ¹ to R ¹⁴ each independently represent a hydrogen atom or a substituent. R ³ and R ⁴ may be bonded to each other to form a ring. Either one of R ⁵ and R ⁶ and either one of R ⁷ and R ⁸ may be bonded to each other to form a ring. When X ¹ represents ═CR ¹¹ — and X ² represents ═CR ¹⁴ —, R ¹¹ and R ¹⁴ may be bonded to each other to form a ring. When X ¹ represents —CR ⁹ R ¹⁰ — and X ² represents —CR ¹² R ¹³ —, either one of R ⁹ and R ¹⁰ and either one of R ¹² and R ¹³ may be bonded to each other to form a ring.
R ^X1 to R ^X4 each independently represent a hydrogen atom or a substituent, provided that at least one of R ^X1 to R ^X4 represents an acid-decomposable group, and either one of R ^X1 or R ^X2 and either one of R ^X3 or R ^X4 may be bonded to each other to form a ring.
However, the polymerizable compound represented by the above general formula (1) contains a monovalent substituent represented by the following general formula (2) in the molecule.

In the formula, ^L2 represents a single bond or a divalent linking group, Y represents a polymerizable group, and * represents a bonding position.

In formula (1), the substituents represented by R ¹ to R ¹⁴ are not particularly limited, and examples thereof include a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cycloalkyl group, an aromatic ring group, and the monovalent substituent represented by the above general formula (2).

The alkyl group may be linear or branched, and preferably has a carbon number of 1 to 5. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.
Examples of the alkyl group moiety in the alkoxy group and the alkoxycarbonyl group include the same groups as the alkyl group described above.
The cycloalkyl group preferably has 3 to 15 ring atoms. The cycloalkyl group is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group. The cycloalkyl group may have, for example, one or more (e.g., 1 to 3) methylene groups constituting the ring replaced with a heteroatom (e.g., -O- or -S-), -SO ₂ -, -SO ₃ -, an ester group, a carbonyl group, or a vinylidene group. Furthermore, in these cycloalkyl groups, one or more (e.g., 1 to 2) ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group.
The cycloalkyl group may be condensed with an aromatic ring (such as a benzene ring).
The aromatic ring group may be monocyclic or polycyclic, and preferably has 5 to 15 ring atoms. The aromatic ring group may have one or more (e.g., 1 to 5) heteroatoms (e.g., oxygen atoms, sulfur atoms, nitrogen atoms, etc.) as ring atoms. Examples of the aromatic ring group include a benzene ring group, a naphthalene ring group, an anthracene ring group, a thiazole ring group, and a benzothiazole ring group.

The alkyl group, alkoxy group, alkoxycarbonyl group, and alkenyl group may further have a substituent, for example, a halogen atom (such as a fluorine atom), a hydroxyl group, a nitro group, a cyano group, a cycloalkyl group, and an aromatic ring group.
The cycloalkyl group and the aromatic ring group may further have a substituent, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkenyl group, an aromatic ring group (which may be monocyclic or polycyclic and has, for example, 5 to 15 ring atoms), and a cycloalkyl group (which may be monocyclic or polycyclic and has, for example, 3 to 15 ring atoms).

The ring shown in formula (1) (the ring consisting of the carbon atom to which R ¹ is bonded, the carbon atom to which R ² is bonded, L ¹ , X ¹ , and X ² ) is a six-membered ring.
Here, when ^L1 represents ^-CR3 = ^CR4- , ^R3 and ^R4 may be bonded to each other to form a ring. Also, when ^X1 represents = ^CR11- and ^X2 represents = ^CR14- , ^R11 and ^R14 may be bonded to each other to form a ring. The ring formed here is preferably an alicyclic ring containing an unsaturated bond corresponding to the site of ^L1 and the site of bonding between ^X1 and ^X2 , or an aromatic ring.

The aromatic ring may be monocyclic or polycyclic, and the number of ring atoms is preferably 5 to 20 (preferably 6 to 10). The aromatic ring group may have one or more (for example, 1 to 5) heteroatoms (such as oxygen atoms, sulfur atoms, and nitrogen atoms) as ring atoms.
Examples of the aromatic ring include a benzene ring, a naphthalene ring, a tolylene ring, an anthracene ring, a thiophene ring, a furan ring, a pyrrole ring, a benzothiophene ring, a benzofuran ring, a benzopyrrole ring, a triazine ring, an imidazole ring, a benzimidazole ring, a triazole ring, a thiadiazole ring, and a thiazole ring, and a benzene ring is preferred.
The aromatic ring may further have a substituent, such as those exemplified as the substituents represented by R ¹ to R ¹⁴ .

The alicyclic ring may be monocyclic or polycyclic, and preferably has 5 to 20 (preferably 6 to 10) ring atoms. The alicyclic ring may have one or more (for example, 1 to 5) heteroatoms (oxygen atoms, sulfur atoms, nitrogen atoms, etc.) as ring atoms. The alicyclic ring contains unsaturated bonds at positions within the ring corresponding to the site of ^L1 and the site of bonding between ^X1 and ^X2 . The alicyclic ring may further contain an unsaturated bond. Furthermore, the alicyclic ring may have a carbon atom substituted with a carbonyl carbon in the ring.
Examples of the alicyclic ring include cyclopentene, cyclohexene, cycloheptene, and cyclooctadiene.
The alicyclic ring may further have a substituent, such as those exemplified as the substituents represented by R ¹ to R ¹⁴ .

Furthermore, when L ¹ represents -CR ⁵ R ⁶ -CR ⁷ R ⁸ -, either one of R ⁵ and R ⁶ and either one of R ⁷ and R ⁸ may be bonded to each other to form a ring. Furthermore, when X ¹ represents -CR ⁹ R ¹⁰ - and X ² represents -CR ¹² R ¹³ -, either one of R ⁹ and R ¹⁰ and either one of R ¹² and R ¹³ may be bonded to each other to form a ring. The ring formed here is preferably an alicyclic ring. The alicyclic ring may be monocyclic or polycyclic, and preferably has 5 to 20 (preferably 6 to 10) ring atoms. The alicyclic ring may have one or more (e.g., 1 to 5) heteroatoms (such as oxygen atoms, sulfur atoms, and nitrogen atoms) as ring atoms. The alicyclic ring may contain an unsaturated bond at a position within the ring other than the position of L ¹ and the bonding site between X ¹ and X ² . In addition, in the alicyclic ring, a carbon atom in the ring may be substituted with a carbonyl carbon.
Examples of the alicyclic ring include cyclopentane, cyclohexane, cycloheptane, and cyclooctane.
The alicyclic ring may further have a substituent, such as those exemplified as the substituents represented by R ¹ to R ¹⁴ .

In general formula (1), examples of the substituents represented by R ^X1 to R ^X4 include acid-decomposable groups and the substituents exemplified as the substituents represented by R ¹ to R ¹⁴ .
The acid-decomposable group has the same meaning as the acid-decomposable group described for the specific acid-decomposable resin A in the first embodiment, and preferred embodiments are also the same. The specific acid-decomposable resin B formed from the specific monomer B having an acid-decomposable group has a repeating unit (acid-decomposable repeating unit) having an acid-decomposable group. Due to the presence of this acid-decomposable repeating unit, the specific acid-decomposable resin B exhibits a property in which the polarity increases under the action of acid, increasing its solubility in alkaline developers and decreasing its solubility in organic solvents.

At least one of R ^X1 to R ^X4 represents an acid-decomposable group. In terms of more excellent effects of the present invention, it is preferable that at least two of R ^X1 to R ^X4 represent acid-decomposable groups, more preferable that two of R ^X1 to R ^X4 represent acid-decomposable groups, and even more preferable that R ^X1 and R ^X3 represent acid-decomposable groups.
Furthermore, either one of R ^X1 and R ^X2 and either one of R ^X3 and R ^X4 may be bonded to each other to form a ring. The ring formed here is preferably an alicyclic ring. The alicyclic ring may be monocyclic or polycyclic, and preferably has 5 to 20 (preferably 5 to 10) ring atoms. The alicyclic ring may have one or more (for example, 1 to 5) heteroatoms (such as oxygen atoms, sulfur atoms, and nitrogen atoms) as ring atoms. The alicyclic ring may contain an unsaturated bond within the ring. Furthermore, the alicyclic ring may have a carbon atom substituted with a carbonyl carbon.
When two of R ^X1 to R ^X4 represent an acid-decomposable group, the other two preferably represent a hydrogen atom, as this will provide better effects of the present invention.

In formula (2), ^L2 represents a single bond or a divalent linking group.
Examples of the divalent linking group represented by ^L2 include -CO-, -NR ^d -, -O-, -S-, -SO-, -SO ₂ -, alkylene groups, cycloalkylene groups, alkenylene groups, divalent aliphatic heterocyclic groups, divalent aromatic heterocyclic groups, divalent aromatic hydrocarbon ring groups, and divalent linking groups combining a plurality of these. The above-mentioned alkylene groups, cycloalkylene groups, alkenylene groups, divalent aliphatic heterocyclic groups, divalent aromatic heterocyclic groups, and divalent aromatic hydrocarbon ring groups may further have a substituent. R ^d in the above -NR ^d - represents a hydrogen atom or an organic group. The organic group is preferably an alkyl group (for example, having 1 to 6 carbon atoms).

The alkylene group may be linear or branched, and preferably has 1 to 6 carbon atoms.
The cycloalkylene group preferably has 3 to 15 carbon atoms.
The alkenylene group preferably has 2 to 6 carbon atoms.
The divalent aliphatic heterocyclic group is preferably a ring having 5 to 10 ring atoms and containing a heteroatom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom as a ring member atom.
The divalent aromatic heterocyclic group is preferably a ring having 5 to 10 ring atoms and containing a heteroatom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom as a ring atom.
The divalent aromatic hydrocarbon ring group includes rings having 6 to 10 ring atoms.

Among these, the divalent linking group represented by ^L2 is preferably —CO—, —NR ^d —, —O—, —S—, —SO—, —SO ₂ —, an alkylene group, a divalent aromatic hydrocarbon ring group, or a divalent linking group formed by combining a plurality of these groups.
Examples of the "divalent linking group formed by combining a plurality of these" include -alkylene group-O-alkylene group-phenylene group-.
In the divalent linking group represented by L ² , the position adjacent to the polymerizable group represented by Y is preferably not —CO—, —NR ^d —, —O—, —S—, —SO—, or —SO ₂ —.

Examples of the polymerizable group represented by Y include a radically polymerizable group and a cationically polymerizable group, with a radically polymerizable group being preferred and an ethylenically unsaturated group being more preferred.
Examples of types of ethylenically unsaturated groups include vinyl groups, maleimide groups, CH ₂ ═CR ^T - (R ^T represents a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, and iodine atom)), CH ₂ ═CR ^Q -CO-O- (R ^Q represents an alkyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, and iodine atom) or a hydrogen atom. When ^{R Q} represents a methyl group or a hydrogen atom, CH ₂ ═CR ^Q -CO-O- corresponds to a (meth)acrylic group, and when R ^Q represents a chlorine atom, CH ₂ ═CR ^Q -CO-O- corresponds to an α-chloroacrylic group), and the like. In view of the superior effects of the present invention, a (meth)acrylic group is preferred. In other words, specific monomer B is preferably a (meth)acrylic compound. Among these, the polymerizable group is more preferably a methacrylic group, in that the effects of the present invention are more excellent.
The specific monomer B is preferably a monofunctional monomer.

The specific monomer B contains a monovalent substituent represented by the above general formula (2) in the molecule. The position at which the monovalent substituent represented by the above general formula (2) is introduced into the specific monomer B is not particularly limited, and may be, for example, introduced into ^R1 and ^R2 , introduced onto a ring formed by ^R3 and ^R4 bonding to each other, introduced onto a ring formed by ^R11 and ^R14 bonding to each other, introduced onto a ring formed by either one of ^R5 and ^R6 and either one of ^R7 and ^R8 bonding to each other, or introduced onto a ring formed by either one of ^R9 and ^R10 and either one of ^R12 and ^R13 bonding to each other.
The specific monomer B is preferably a monofunctional monomer, that is, the specific monomer B preferably has one monovalent substituent represented by the above general formula (2).

In addition, in formula (1), suitable combinations of L ¹ , X ¹ and X ² (L ¹ , X ¹ , X ² ) include (—CR ³ ═CR ⁴ —, ═CR ¹¹ —, ═CR ¹⁴ —), (—CR ³ ═CR ⁴ —, —O—, —CO—), and (—CR ³ ═CR ⁴ —, —CO—, —O—).
When (L ¹ , X ¹ , X ² ) are (-CR ³ ═CR ⁴ -, ═CR ¹¹ -, ═CR ¹⁴ -), a specific example of the specific monomer B is a compound represented by the following general formula (AX): The polymerizable compound represented by the following general formula (AX) has 9,10-dihydroanthracene as its basic skeleton.

In formula (AX), R ¹ , R ² , and R ^X1 to R ^X4 each independently have the same meaning as R ¹ , R ² , and R ^X1 to R ^X4 in formula (1), and the preferred embodiments are also the same.
R ²² and R ²³ each independently represent a substituent. Examples of the substituents represented by ^{R 22} and R ²³ include those exemplified as the substituents represented by R ¹ to R ¹⁴ .
m and n each independently represent an integer of 0 to 4;
However, the polymerizable compound represented by the general formula (AX) contains the monovalent substituent represented by the general formula (2) in the molecule. Specifically, it is preferable that the substituent is introduced into any one of the positions R ¹ , R ² , R ²² and R ²³ .

A preferred embodiment of specific monomer B is a polymerizable compound represented by the following general formula (3) and a polymerizable compound represented by the following general formula (4):

The polymerizable compound represented by general formula (3) has the same meaning and preferred embodiments as general formula (1), except that it has a monovalent substituent represented by general formula (2) at the position of R ^1. The polymerizable compound represented by general formula (3) is preferably a monofunctional monomer.

The polymerizable compound represented by general formula (4) has the same meaning and preferred embodiments as general formula (1), except that L ¹ represents -CR ³ ═CR ⁴ -. The polymerizable compound represented by general formula (4) is preferably a monofunctional monomer.

In general formula (4), the monovalent substituent represented by general formula (2) is preferably introduced at any of R ¹ to R ⁴ or onto the ring formed by bonding R ³ and R ⁴ together.
A preferred embodiment of the polymerizable compound represented by formula (4) is one in which X ¹ represents —O— and X ² represents —CO—.
Another preferred embodiment of the polymerizable compound represented by general formula (4) is one in which ^X1 represents —O—, ^X2 represents —CO—, and ^R3 and ^R4 are bonded to each other to form an alicyclic ring.
Another preferred embodiment of the polymerizable compound represented by formula (4) is one in which X ¹ represents —CO— and X ² represents —O—.
Another preferred embodiment of the polymerizable compound represented by general formula (4) is one in which ^X1 represents —CO—, ^X2 represents —O—, and ^R3 and ^R4 are bonded to each other to form an alicyclic ring.

As the polymerizable compound represented by the above general formula (3), a polymerizable compound represented by the following general formula (5) is preferred. Note that the polymerizable compound represented by the following general formula (5) has 9,10-dihydroanthracene as its basic skeleton.

In formula (5), R ²⁴ and R ^X1 to R ^X4 each independently have the same meaning as R ² and R ^X1 to R ^X4 in formula (1), and the preferred embodiments are also the same.
^R21 represents a hydrogen atom or a substituent. Examples of the substituent represented by ^R21 include an alkyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom). ^R21 is preferably a hydrogen atom or a methyl group, and more preferably a methyl group.
R ²² and R ²³ each independently represent a substituent. Examples of the substituents represented by ^{R 22} and R ²³ include those exemplified as the substituents represented by R ¹ to R ¹⁴ .
m and n each independently represent an integer of 0 to 4;
L ²¹ may be a single bond or a divalent linking group.
Examples of the divalent linking group represented by L ²¹ include the same as the divalent linking group represented by L ² in general formula (2), and preferred embodiments are also the same.

Specific monomer B is preferably a polymerizable compound whose homopolymer has a glass transition temperature of 220°C or higher. The glass transition temperature of the homopolymer of specific monomer B is intended to be the value obtained by the measurement method described above for the glass transition temperature of the homopolymer of specific monomer A.

The glass transition temperature of the homopolymer of specific monomer B is preferably 250°C or higher, more preferably 280°C or higher, and particularly preferably 300°C or higher, in order to achieve the effects of the present invention more effectively. There is no upper limit, but a temperature of 400°C or lower is preferred.

The protecting group value of specific monomer B is preferably 3.40 mmol/g or more, as this provides better effects of the present invention. The protecting group value represents the molar amount (mmol/g) of acid-decomposable groups relative to the mass of specific monomer B (polymerizable compound). There is no particular upper limit, but a value of 6.0 mmol/g or less is preferred. The protecting group value is more preferably 3.50 mmol/g or more, and even more preferably 3.60 mmol/g or more, as this provides better effects of the present invention.

The molecular weight of specific monomer B is not particularly limited, but is preferably 400 or more. The upper limit is preferably 1,000 or less, more preferably 800 or less, and even more preferably 700 or less.

Specific Monomer B can be synthesized by known methods. Specifically, it can be obtained by a method such as adding an alkene compound to a conjugated diene compound via a Diels-Alder reaction to form an unsaturated six-membered ring structure.

Specific examples (Group A and Group B) of the specific monomer B are shown below, but the specific monomer B is not limited thereto. Note that all of the compounds belonging to (Group A) of the specific monomer A shown below correspond to compounds having 9,10-dihydroanthracene as a basic skeleton.
(Group A)

(Group B)

[Electronic Device Manufacturing Method]
The present invention also relates to a method for manufacturing an electronic device, which includes a pattern formation method using the resist composition of the first or second embodiment described above, and to an electronic device manufactured by this manufacturing method.
The electronic device of the present invention is suitably mounted in electrical and electronic equipment (such as home appliances, OA (Office Automation), media-related equipment, optical equipment, and communication equipment).

[Compound]
The present invention also relates to a polymerizable compound (specific monomer B) represented by the above-mentioned general formula (1). The specific monomer B is as described above.

[resin]
The present invention also relates to a resin (specific acid-decomposable resin B) having a repeating unit derived from the polymerizable compound (specific monomer B) represented by the above-mentioned general formula (1). The specific acid-decomposable resin B is as described above.

The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, processing details, and processing procedures shown in the following examples can be modified 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.

[Various components of actinic ray- or radiation-sensitive resin composition]
〔resin〕
The resins (A-1 to A-23, B-1 to B-10) shown in Table 5 are shown below. Resins A-1 to A-23 and B-1 to B-10 were synthesized in accordance with the synthesis method described for resin A-10 described below.
Table 1 shows the mass ratios of the repeating units constituting the resins (A-1 to A-23, B-1 to B-10) shown in Table 5, the weight average molecular weights (Mw), and the dispersities (Mw/Mn).
The weight average molecular weight (Mw) and dispersity (Mw/Mn) of Resins A-1 to A-23 and B-1 to B-10 were measured by GPC (carrier: tetrahydrofuran (THF)) and are shown as polystyrene equivalents.

Tables 2 to 4 show the structures of the monomers (polymerizable compounds) used in the synthesis of Resins A-1 to A-23 and B-1 to B-10 shown in Table 1. Among the monomers shown below, M-55 to M-73 correspond to monomers (specific monomer A) having a glass transition temperature of 220°C or higher in the homopolymer and a protecting group value of 3.40 mmol/g or higher.
Among the following monomers M-55 to M-73, M-55, M-58 to M-61, and M-67 to M-72 correspond to the polymerizable compound (specific monomer B) represented by the above-mentioned general formula (1).

Monomers M-55 to M-73 were synthesized in accordance with the synthesis method described for resin M-55 below.

Tables 2 to 4 also show the glass transition temperature and protecting group value (mmol equivalent per 1 g of monomer (mmol/g)) of the homopolymer of each monomer.
The glass transition temperatures of the homopolymers of each monomer shown in Tables 2 to 4 were measured by the following method.

<<Method for measuring the glass transition temperature (Tg) of the homopolymer of each monomer shown in Tables 2 to 4>>
<1> Each monomer shown in Tables 2 to 4 is synthesized in a charge composition of 30 mass% and cyclohexyl methacrylate in 70 mass%, to obtain a copolymer P2 having a weight average molecular weight of 60,000 or more (specifically, a weight average molecular weight of 60,000 to 100,000).
<2> The Tg of the obtained copolymer P2 is evaluated using a differential scanning calorimeter (Shimadzu Corporation's "Differential Scanning Calorimeter DSC-60 Plus Measurement System").
The Tg was measured under the following conditions.
Measurement conditions: Under an air flow, the temperature was raised from room temperature to 150° C. The temperature was raised at a rate of 5° C./min for two cycles, and the Tg of the copolymer P2 was obtained.
<3> Using the following formula (1) based on the Fox formula, the Tg of the homopolymer of each monomer shown in Tables 2 to 4 is calculated, assuming that the Tg of the homopolymer of cyclohexyl methacrylate is 98°C.

Formula (1) 1/Tg=w1/Tg1+w2/Tg2
In formula (1), Tg represents the Tg(K) of copolymer P2. Tg1 represents the homopolymer Tg(K) of each monomer shown in Tables 2 to 4. Tg2 represents the homopolymer Tg(K) of cyclohexyl methacrylate. w1 represents the mass fraction of repeating units derived from each monomer shown in Tables 2 to 4 relative to all repeating units in copolymer P2. w2 represents the mass fraction of repeating units derived from a homopolymer of cyclohexyl methacrylate relative to all repeating units in copolymer P2. When calculating the homopolymer Tg of each monomer, w1 is set to 0.3 and w2 is set to 0.7.

Note that the monomers M-55, M-59 to M-61, M-67 to M-69, and M-71 to M-72 shown below all correspond to compounds with 9,10-dihydroanthracene as the basic skeleton.

<<Synthesis Example>>
<Synthesis Example 1: Synthesis of M-55>
(Step 1: Synthesis of fumaric acid ester)

A mixed solution of potassium t-butoxide (146.8 g) and t-butanol (1,300 g) was heated to 35° C. under a nitrogen stream. Fumarolic acid chloride (100.0 g) was added dropwise to this solution while stirring, and after the dropwise addition was completed, the temperature was raised to 50° C. and the solution was stirred for 4 hours.
After allowing the obtained liquid to cool to room temperature, 200 ml of saturated sodium bicarbonate water was added dropwise with stirring to quench the reaction. Thereafter, the remaining t-BuOH was removed using an evaporator. Next, the liquid was separated using 1200 ml of ethyl acetate and 1200 ml of water, and the separated ethyl acetate layer was dried over magnesium sulfate. After drying, filtration was carried out, and the liquid after filtration was concentrated using an evaporator. 50 ml of isopropanol was added to the obtained concentrated liquid, which was then heated and dissolved, and 50 ml of water was added to cause crystallization. The obtained crystallized product (powder) was collected by filtration to obtain the target product (FA-TBm: yield 70.1 g, 47% yield).

(Step 2: Synthesis of precursor compound (M'-55))

Anthracenemethanol (50.0 g) and FA-TBm (65.8 g) were added to toluene (250 ml), heated to 115°C in an oil bath, and reacted under reflux for 16 hours. The toluene was removed using an evaporator, and 36 ml of methanol was added. The mixture was stirred while cooling on ice. The precipitated powder was filtered to obtain the desired product (M'-55: yield 80 g, 76.3%).

(Step 3: Synthesis of compound M-55)

M'-55 (80 g) was dissolved in tetrahydrofuran (185 ml), and methacrylic acid chloride (46 g) was added dropwise with ice cooling, followed by triethylamine (44.5 g). After the dropwise addition, the resulting reaction solution was reacted for an additional hour, and then this reaction solution was added to 1200 ml of ethyl acetate and 1200 m of saturated sodium bicarbonate water and stirred overnight. Thereafter, the ethyl acetate layer was extracted by a separation operation and dried over magnesium sulfate. After drying, filtration was carried out, and the filtered liquid was then concentrated in an evaporator. 360 ml of methanol was added to the resulting concentrate, and the mixture was stirred to cause crystallization. The resulting crystallized product (powder) was collected by filtration to obtain the target product (M-55: yield 75.8 g, 82% yield).
FIG. 1 shows the ¹ H-NMR chart of the obtained M-55.

<Synthesis Example 2: Synthesis of Resin A-10>
Cyclohexanone (15.2 g) was heated to 85 ° C. under a nitrogen stream. While stirring this liquid, a mixed solution of the following monomer M-19 (31.3 g, 50.4 mass% PGMEA solution), the following monomer M-60 (29.3 g), cyclohexanone (27.1 g), and a cyclohexanone solution [10 mass%] (33.8 g) of dimethyl 2,2'-azobisisobutyrate [V-601, manufactured by Wako Pure Chemical Industries, Ltd.] was added dropwise over 6 hours to obtain a reaction liquid. After completion of the dropwise addition, the reaction liquid was stirred for an additional 2 hours at 85 ° C. After allowing the obtained reaction liquid to cool, it was reprecipitated with a large amount of heptane/ethyl acetate (mass ratio 9:1), filtered, and the obtained solid was vacuum dried to obtain resin A-10 (39 g). All of the above operations were performed under yellow light.

[Photoacid generator]
The structures of the photoacid generators (B-1 to B-11) shown in Table 5 are shown below.

[Hydrophobic resin]
The structures, weight average molecular weights (Mw), and dispersities (Mw/Mn) of the hydrophobic resins (P-1 to P-3) shown in Table 5 are shown below.
The weight average molecular weight (Mw) and dispersity (Mw/Mn) of the hydrophobic resins P-1 to P-3 were measured by GPC (carrier: THF) and are shown as polystyrene equivalents.
Hydrophobic resin P-1: a polymer made from the following monomer ME-1 (Mw: 8,700, Mw/Mn: 1.56)
Hydrophobic resin P-2: a polymer made from the following monomer ME-5 (Mw: 7,600, Mw/Mn: 1.62)
Hydrophobic resin P-3: a polymer made from the following monomer ME-2 (Mw: 5,800, Mw/Mn: 1.55)

[Surfactant]
The surfactants shown in Table 5 are as follows:
H-1: Megafac F176 (DIC Corporation, fluorine-based surfactant)

〔solvent〕
The solvents shown in Table 5 are as follows:
G-1: Propylene glycol monomethyl ether acetate (PGMEA)
G-2: Propylene glycol monomethyl ether (PGME)
G-5: Cyclopentanone G-8: γ-butyrolactone

[Preparation of actinic ray- or radiation-sensitive resin composition and pattern formation: EUV exposure]
[Preparation of actinic ray- or radiation-sensitive resin composition]
The components shown in Table 5 were mixed to a solids concentration of 1.4% by mass. The resulting mixture was then filtered by passing it through, in order, first a polyethylene filter with a pore size of 50 nm, then a nylon filter with a pore size of 10 nm, and finally a polyethylene filter with a pore size of 5 nm, to prepare actinic ray-sensitive or radiation-sensitive resin compositions (hereinafter also referred to as "resist compositions") (Re-1 to Re-23, HRe-1 to HRe-10). The solids content refers to all components other than the solvent. The resulting resist compositions were used in the examples and comparative examples.

Table 5 is shown below.
In the table, the "content" column for each component indicates the content (mass %) of each component relative to the total solid content. In the "solvent" column, the "mixing ratio" indicates the mixing ratio (mass ratio) of each solvent.

[Pattern Formation and Evaluation (1): EUV Exposure, Alkaline Development]
<Pattern formation>
An underlayer film-forming composition AL412 (manufactured by Brewer Science) was applied to a silicon wafer having a diameter of 12 inches and baked at 205°C for 60 seconds to form an underlayer film having a thickness of 20 nm. The resist composition prepared as described above was applied thereon and baked at 100°C for 60 seconds to form a resist film having a thickness of 20 nm.
Exposure was performed using an EUV exposure machine (manufactured by ASML; NXE3350, NA 0.33, dipole 45°, outer sigma 0.87, inner sigma 0.60) through a reflective mask with a line size of 20 nm and a line:space ratio of 1:1.
The wafer was then developed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) for 30 seconds, rinsed with water for 20 seconds, and then rotated at 2000 rpm for 40 seconds to form a positive pattern with a line size of 20 nm and a line:space ratio of 1:1.

<Evaluation>
(Line width roughness (LWR performance, nm))
The pattern obtained by the above method was observed from above using a critical dimension scanning electron microscope (SEM (Hitachi, Ltd. S-9380II)). The line width of the pattern was observed at 250 points, and the measurement variation was evaluated at 3σ to obtain the LWR (nm). The smaller the LWR value, the better the LWR performance. The results are shown in Table 6.
The LWR performance is preferably less than 4.00 nm, more preferably 3.50 nm or less, and even more preferably 3.00 nm or less.

(Resolution evaluation (limiting resolution, nm))
In the above <Pattern formation>, exposure is carried out at an optimum exposure dose Eop (μC/cm ² ) (exposure dose when the pattern formed using the resist composition reproduces the pattern of the mask used for exposure).
Next, a test was conducted to form a line and space pattern by gradually changing the exposure dose from the optimum exposure dose Eop. In this case, the minimum dimension of the pattern that could be resolved without collapsing was determined using a critical dimension scanning electron microscope (SEM (Hitachi, Ltd. S-9380II)). This was defined as the "limiting resolution (nm)." The smaller the limiting resolution value, the better the resolution. The results are shown in Table 6.
The resolution is preferably less than 15.0 nm, more preferably 13.0 nm or less, and even more preferably 12.0 nm or less.

The results shown in the table confirm that the resist compositions of the examples have excellent resolution and also excellent LWR performance of the patterns formed.

(Results for specific monomer A)
Furthermore, by comparing the individual examples, it was confirmed that when the raw material monomer for the acid-decomposable repeating unit in the acid-decomposable resin contained in the resist composition is a monomer having a glass transition temperature of 300°C or higher in the homopolymer and a protecting group value of 3.40 mmol/g or higher (preferably a monomer having a glass transition temperature of 300°C or higher in the homopolymer and a protecting group value of 3.50 mmol/g or higher), the resist composition exhibits superior resolution and the formed pattern also exhibits superior LWR performance.
Furthermore, it was confirmed that when the polar group protected by the protecting group in the structure of the acid-decomposable repeating unit is a carboxyl group, the resist composition exhibits superior resolution and the LWR performance of the formed pattern is also superior.

(Results for specific monomer B)
Furthermore, for example, when the results of Example 4 and Example 8 are compared, it was confirmed that when the raw material monomer for the acid-decomposable repeating unit in the acid-decomposable resin contained in the resist composition is a polymerizable compound represented by general formula (1) above, particularly when it has a structure represented by general formula (AX) above, the resist composition exhibits superior resolution and the formed pattern also exhibits superior LWR performance.
Furthermore, for example, by comparing the results of Examples 1, 6, and 7, it was confirmed that when the polymerizable group in the polymerizable compound represented by the above-mentioned general formula (1) is a (meth)acrylic group (preferably a methacrylic group), the resist composition has superior resolution and the LWR performance of the formed pattern is also superior.

Furthermore, by comparing Examples 1, 11, 21, and 22, it was confirmed that in the polymerizable compound represented by the above-mentioned general formula (1), when the type of acid-decomposable group is the group represented by the above-mentioned general formula (O1), and two of R ₁₁ to R ₁₃ do not bond to each other to form a ring, the resist composition has better resolution and the LWR performance of the formed pattern is also better.

Furthermore, by comparing Example 1 and Example 13, it was confirmed that when the number of acid-decomposable groups in the polymerizable compound represented by the above-mentioned general formula (1) is two, the resist composition has better resolution and the LWR performance of the formed pattern is also better.

Furthermore, by comparing Examples 1, 9, and 14, it was confirmed that in the polymerizable compound represented by the above-mentioned general formula (1), when two of R ^X1 to R ^X4 represent an acid-decomposable group and the other two represent a hydrogen atom, the resist composition has superior resolution and the LWR performance of the formed pattern is also superior.

On the other hand, the resist composition of the comparative example did not achieve the desired performance.

[Pattern Formation and Evaluation (2): EUV Exposure, Organic Solvent Development]
<Pattern formation>
An underlayer film-forming composition AL412 (manufactured by Brewer Science) was applied to a silicon wafer having a diameter of 12 inches and baked at 205°C for 60 seconds to form an underlayer film having a thickness of 20 nm. A resist composition shown in Table 7 was applied thereon and baked at 100°C for 60 seconds to form a resist film having a thickness of 30 nm.
Using an EUV exposure device (Micro Exposure Tool, NA 0.3, Quadruple, outer sigma 0.68, inner sigma 0.36, manufactured by Exitech), a pattern was irradiated onto the silicon wafer having the resist film so that the average line width of the resulting pattern was 20 nm. 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 n-butyl acetate for 30 seconds, and then spin-dried to obtain a negative pattern.

<Evaluation>
The obtained negative pattern was evaluated for line width roughness (LWR performance, nm) and resolution (limiting resolution, nm) in the same manner as in the above-mentioned [Pattern formation and evaluation (1): EUV exposure, alkaline development]. The results are shown in Table 7.

The results shown in the table confirm that the resist compositions of the examples can form patterns with excellent LWR and resolution.

(Results for specific monomer A)
Furthermore, by comparing the individual examples, it was confirmed that when the raw material monomer for the acid-decomposable repeating unit in the acid-decomposable resin contained in the resist composition is a monomer having a glass transition temperature of 300°C or higher in the homopolymer and a protecting group value of 3.40 mmol/g or higher (preferably a monomer having a glass transition temperature of 300°C or higher in the homopolymer and a protecting group value of 3.50 mmol/g or higher), the resist composition exhibits superior resolution and the formed pattern also exhibits superior LWR performance.
Furthermore, it was confirmed that when the polar group protected by the protecting group in the structure of the acid-decomposable repeating unit is a carboxyl group, the resist composition exhibits superior resolution and the LWR performance of the formed pattern is also superior.

(Results for specific monomer B)
Furthermore, for example, when the results of Example 24 and Example 28 are compared, it was confirmed that when the raw material monomer for the acid-decomposable repeating unit in the acid-decomposable resin contained in the resist composition is a polymerizable compound represented by general formula (1) above, particularly when it has a structure represented by general formula (AX), the resist composition exhibits superior resolution and the formed pattern also exhibits superior LWR performance.
Furthermore, for example, by comparing the results of Examples 21, 26, and 27, it was confirmed that when the polymerizable group in the polymerizable compound represented by the general formula (1) above is a (meth)acrylic group (preferably a methacrylic group), the resist composition has superior resolution and the LWR performance of the formed pattern is also superior.

Furthermore, by comparing Examples 21, 31, 41, and 42, it was confirmed that in the polymerizable compound represented by the general formula (1) described above, when the type of acid-decomposable group is the group represented by the general formula (O1) described above, and two of R ₁₁ to R ₁₃ do not bond to each other to form a ring, the resist composition has better resolution and the LWR performance of the formed pattern is also better.

Furthermore, by comparing Example 21 and Example 33, it was confirmed that when the number of acid-decomposable groups in the polymerizable compound represented by the above-mentioned general formula (1) is two, the resist composition has better resolution and the LWR performance of the formed pattern is also better.

Furthermore, by comparing Examples 21, 29, and 34, it was confirmed that in the polymerizable compound represented by the above-mentioned general formula (1), when two of R ^X1 to R ^X4 represent an acid-decomposable group and the other two represent a hydrogen atom, the resist composition has superior resolution and the LWR performance of the formed pattern is also superior.

On the other hand, the resist composition of the comparative example did not achieve the desired performance.

Claims (8)

An actinic ray-sensitive or radiation-sensitive resin composition comprising a resin having a repeating unit derived from a polymerizable compound represented by the following general formula (1) and a photoacid generator:

In the formula, L ¹ represents —CR ³ ═CR ⁴ — or —CR ⁵ R ⁶ —CR ⁷ R ⁸ —.
X ¹ represents —O—, —CR ⁹ R ¹⁰ —, or ═CR ¹¹ —.
X ² represents —O—, —CO—, —CR ¹² R ¹³ — or ═CR ¹⁴ —.
The bond between ^X1 and ^X2 , represented by a solid line and a dotted line, represents a single bond or a double bond. However, when the bond between ^X1 and ^X2 represents a double bond, ^X1 represents =CR ¹¹ -, and ^X2 represents =CR ¹⁴ -. Furthermore, when the bond between ^X1 and ^X2 represents a single bond, ^X1 represents -O- or -CR ⁹ R ¹⁰ -, and ^X2 represents -O-, -CO-, or -CR ¹² R ¹³ -.
R ¹ to R ¹⁴ each independently represent a hydrogen atom or a substituent. R ³ and R ⁴ may be bonded to each other to form a ring. Either one of R ⁵ and R ⁶ and either one of R ⁷ and R ⁸ may be bonded to each other to form a ring. When X ¹ represents ═CR ¹¹ — and X ² represents ═CR ¹⁴ —, R ¹¹ and R ¹⁴ may be bonded to each other to form a ring. When X ¹ represents —CR ⁹ R ¹⁰ — and X ² represents —CR ¹² R ¹³ —, either one of R ⁹ and R ¹⁰ and either one of R ¹² and R ¹³ may be bonded to each other to form a ring.
R ^X1 to R ^X4 each independently represent a hydrogen atom or a substituent, provided that at least one of R ^X1 to R ^X4 represents an acid-decomposable group, and either one of R ^X1 and R ^X2 and either one of R ^X3 and R ^X4 may be bonded to each other to form a ring.
However, the polymerizable compound represented by the general formula (1) contains a monovalent substituent represented by the following general formula (2) in the molecule.

In the formula, ^L2 represents a single bond or a divalent linking group, Y represents a polymerizable group, and * represents a bonding position. 2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 , wherein the polymerizable compound represented by general formula (1) is a polymerizable compound represented by the following general formula (3):

In the formula, L ¹ represents —CR ³ ═CR ⁴ — or —CR ⁵ R ⁶ —CR ⁷ R ⁸ —.
X ¹ represents —O—, —CR ⁹ R ¹⁰ —, or ═CR ¹¹ —.
X ² represents —O—, —CO—, —CR ¹² R ¹³ — or ═CR ¹⁴ —.
The bond between ^X1 and ^X2 , represented by a solid line and a dotted line, represents a single bond or a double bond. However, when the bond between ^X1 and ^X2 represents a double bond, ^X1 represents =CR ¹¹ -, and ^X2 represents =CR ¹⁴ -. Furthermore, when the bond between ^X1 and ^X2 represents a single bond, ^X1 represents -O- or -CR ⁹ R ¹⁰ -, and ^X2 represents -O-, -CO-, or -CR ¹² R ¹³ -.
R ² to R ¹⁴ each independently represent a hydrogen atom or a substituent. R ³ and R ⁴ may be bonded to each other to form a ring. Either one of R ⁵ and R ⁶ and either one of R ⁷ and R ⁸ may be bonded to each other to form a ring. When X ¹ represents ═CR ¹¹ — and X ² represents ═CR ¹⁴ —, R ¹¹ and R ¹⁴ may be bonded to each other to form a ring. When X ¹ represents —CR ⁹ R ¹⁰ — and X ² represents —CR ¹² R ¹³ —, either one of R ⁹ and R ¹⁰ and either one of R ¹² and R ¹³ may be bonded to each other to form a ring.
R ^X1 to R ^X4 each independently represent a hydrogen atom or a substituent, provided that at least one of R ^X1 to R ^X4 represents an acid-decomposable group, and either one of R ^X1 and R ^X2 and either one of R ^X3 and R ^X4 may be bonded to each other to form a ring.
^L2 represents a single bond or a divalent linking group.
Y represents a polymerizable group. 2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 , wherein the polymerizable compound represented by general formula (1) is a polymerizable compound represented by the following general formula (4):

In the formula, X ¹ represents —O—, —CR ⁹ R ¹⁰ —, or ═CR ¹¹ —.
X ² represents —O—, —CO—, —CR ¹² R ¹³ — or ═CR ¹⁴ —.
The bond between ^X1 and ^X2 , represented by a solid line and a dotted line, represents a single bond or a double bond. However, when the bond between ^X1 and ^X2 represents a double bond, ^X1 represents =CR ¹¹ -, and ^X2 represents =CR ¹⁴ -. Furthermore, when the bond between ^X1 and ^X2 represents a single bond, ^X1 represents -O- or -CR ⁹ R ¹⁰ -, and ^X2 represents -O-, -CO-, or -CR ¹² R ¹³ -.
R ¹ to R ⁴ and R ⁹ to R ¹⁴ each independently represent a hydrogen atom or a substituent. R ³ and R ⁴ may be bonded to each other to form a ring. When X ¹ represents ═CR ¹¹ — and X ² represents ═CR ¹⁴ —, R ¹¹ and R ¹⁴ may be bonded to each other to form a ring. When X ¹ represents —CR ⁹ R ¹⁰ — and X ² represents —CR ¹² R ¹³ —, either one of R ⁹ and R ¹⁰ and either one of R ¹² and R ¹³ may be bonded to each other to form a ring.
R ^X1 to R ^X4 each independently represent a hydrogen atom or a substituent, provided that at least one of R ^X1 to R ^X4 represents an acid-decomposable group, and either one of R ^X1 or R ^X2 and either one of R ^X3 or R ^X4 may be bonded to each other to form a ring.
However, the polymerizable compound represented by the general formula (4) contains a monovalent substituent represented by the following general formula (2) in the molecule.

In the formula, ^L2 represents a single bond or a divalent linking group, Y represents a polymerizable group, and * represents a bonding position. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 3 , wherein at least two of R ^X1 to R ^X4 represent an acid-decomposable group. 2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 , wherein the polymerizable compound represented by general formula (1) is a polymerizable compound represented by the following general formula (5):

In the formula, ^L21 represents a single bond or a divalent linking group. ^Rx1 and ^Rx3 each independently represent an acid-decomposable group. ^Rx2 and ^Rx4 each independently represent a hydrogen atom or a substituent. ^Rx2 and ^Rx4 may be bonded to each other to form a ring. ^R21 represents a hydrogen atom or a substituent. ^R22 and ^R23 each independently represent a substituent. m and n each independently represent an integer of 0 to 4. ^R24 represents a hydrogen atom or a substituent. A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 5 . A step of forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 5 ;
exposing the resist film to light;
developing the exposed resist film using a developer;
A pattern forming method comprising the steps of: A method for manufacturing an electronic device, comprising the pattern forming method according to claim 7 .