WO2023157712A1 - Actinic ray-sensitive or radiation-sensitive resin composition, resist film, pattern formation method, electronic device manufacturing method, and polymer - Google Patents

Abstract

The present invention addresses a first problem of providing an actinic ray-sensitive or radiation-sensitive resin composition from which a pattern having an excellent resolution is formed. The present invention also addresses a second problem of providing a resist film, a pattern formation method, and an electronic device manufacturing method, all of which involve the actinic ray-sensitive or radiation-sensitive resin composition. The present invention further addresses a third problem of providing a polymer that can be provided to the actinic ray-sensitive or radiation-sensitive resin composition.　An actinic ray-sensitive or radiation-sensitive resin composition according to the present invention contains a solvent and a polymer including a repeating unit represented by formula (1) or formula (2). In formula (1), X represents a halogen atom. R¹-R³ each independently represent a hydrogen atom or a substituent group. However, at least one of the R¹ and the R² represents an electron-withdrawing group. In formula (2), X represents a halogen atom. R⁴ represents a hydrogen atom or a substituent group. L¹ and L² each independently represent -CO-, -SO-, or -SO₂-. L³ represents a single bond or a divalent linkage group.

Description

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

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

Since the resist for KrF excimer laser (248 nm), a pattern forming method using chemical amplification has been used in order to compensate for the decrease in sensitivity due to light absorption. For example, in a positive chemical amplification method, first, a photoacid generator contained in an exposed area is decomposed by light irradiation to generate an acid. Then, in the post-exposure baking (PEB: Post Exposure Bake) process or the like, the alkali-insoluble groups of the resin contained in the actinic ray-sensitive or radiation-sensitive resin composition are converted into alkali-soluble groups by the catalytic action of the generated acid. The solubility in the developer is changed by, for example, changing the base. Thereafter, development is performed using, for example, a basic aqueous solution. Thereby, the exposed portion is removed to obtain a desired pattern.
For the miniaturization of semiconductor devices, the wavelength of the exposure light source is shortened and the numerical aperture (NA) of the projection lens is increased. Currently, an exposure machine using an ArF excimer laser with a wavelength of 193 nm as a light source has been developed. ing. Moreover, these days, the pattern formation method which uses extreme ultraviolet rays (EUV light: Extreme Ultraviolet) and an electron beam (EB: Electron Beam) as a light source is also being examined.
Under such circumstances, various structures have been proposed as actinic ray-sensitive or radiation-sensitive resin compositions.

For example, Patent Document 1 discloses a polymer whose main chain is cut by irradiation with EUV light, electron beams, or the like, thereby increasing its solubility in an alkaline aqueous solution.

JP 2020-16699 A

The present inventors prepared and studied an actinic ray-sensitive or radiation-sensitive resin composition containing a predetermined polymer with reference to Patent Document 1, and found that the resolution satisfies the level required these days. It is clear that there is a need for further improvement.

Accordingly, an object of the present invention is to provide an actinic ray-sensitive or radiation-sensitive resin composition which is excellent in the resolution of the formed pattern.
Another object of the present invention is to provide a resist film, a pattern forming method, and an electronic device manufacturing method relating to the actinic ray-sensitive or radiation-sensitive resin composition.
Another object of the present invention is to provide a polymer that can be used in the actinic ray-sensitive or radiation-sensitive resin composition.

The inventors have found that the above problems can be solved by the following configuration.

[1] a polymer containing a specific repeating unit selected from the group consisting of a repeating unit represented by formula (1) described later and a repeating unit represented by formula (2) described later;
An actinic ray-sensitive or radiation-sensitive resin composition containing a solvent.
[2] The actinic ray-sensitive or radiation-sensitive resin composition according to [1], wherein the electron-withdrawing group represents a group represented by any one of formulas (a) to (c) described below.
[3] [1] or [2], wherein the specific repeating unit comprises any one or more repeating units selected from the group consisting of formula (1)-1 described below and formula (2)-1 described below; Actinic ray-sensitive or radiation-sensitive resin composition according to .
[4] The actinic ray-sensitive or radiation-sensitive resin composition according to [3], wherein the specific repeating unit contains a repeating unit represented by formula (2)-1.
[5] The actinic ray-sensitive property according to any one of [1] to [4], wherein the total content of the specific repeating units is 40 to 60 mol% with respect to the total repeating units in the polymer. Or a radiation-sensitive resin composition.
[6] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [5], wherein the polymer further contains a repeating unit represented by formula (3) described below.
[7] The repeating unit represented by the above formula (3) contains any one or more repeating units selected from the group consisting of formulas (3)-1 to (3)-4 described later, [6 ] and the actinic ray-sensitive or radiation-sensitive resin composition.
[8] The actinic ray-sensitive or radiation-sensitive resin composition according to [7], wherein the repeating unit represented by formula (3) contains a repeating unit represented by formula (3)-1.
[9] The actinic ray-sensitive or according to [7] or [8], wherein the repeating unit represented by formula (3) contains a repeating unit represented by formula (3)-1-1 described later. A radiation-sensitive resin composition.
[10] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [9], wherein the polymer has a weight average molecular weight of 30,000 or more.
[11] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [10], further comprising a photodegradable onium salt compound.
[12] A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [11].
[13] 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;
and developing the exposed resist film using a developer containing an organic solvent.
[14] A method for manufacturing an electronic device, including the pattern forming method according to [13].
[15] A polymer comprising a specific repeating unit selected from the group consisting of a repeating unit represented by formula (1) described later and a repeating unit represented by formula (2) described later.
[16] The polymer according to [15], wherein the electron-withdrawing group represents a group represented by any one of formulas (a) to (c) described below.
[17] [15] or [16], wherein the specific repeating unit contains at least one repeating unit selected from the group consisting of formula (1)-1 described below and formula (2)-1 described below; The polymer described in .

According to the present invention, it is possible to provide an actinic ray-sensitive or radiation-sensitive resin composition which is excellent in the resolution of the formed pattern.
Moreover, according to this invention, the resist film, the pattern formation method, and the manufacturing method of an electronic device regarding the said actinic-ray-sensitive or radiation-sensitive resin composition can be provided.
Further, according to the present invention, it is possible to provide a polymer that can be used in the actinic ray-sensitive or radiation-sensitive resin composition.

The present invention will be described in detail below.
The description of the constituent elements described below may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
Regarding the notation of groups (atomic groups) in the present specification, as long as it does not contradict the spirit of the present invention, the notation that does not indicate substituted or unsubstituted includes groups having substituents as well as groups not having substituents. do. For example, an "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). Also, the term "organic group" as used herein refers to a group containing at least one carbon atom.
The substituent is preferably a monovalent substituent unless otherwise specified.
The term "actinic ray" or "radiation" as used herein refers to, for example, the emission line spectrum of a mercury lamp, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays (EUV), X-rays, and electron beams (EB: Electron Beam), etc. As used herein, "light" means actinic rays or radiation.
The term "exposure" as used herein means, unless otherwise specified, not only exposure by the emission line spectrum of a mercury lamp, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays, X-rays, and EUV light, but also electron beams, and It also includes drawing with particle beams such as ion beams.
In the present specification, the term "~" is used to include the numerical values before and after it as lower and upper limits.
The bonding direction of the divalent groups described herein is not limited unless otherwise specified. For example, in the compound represented by the formula "XYZ", when Y is -COO-, Y may be -CO-O- or -O-CO- good too. Further, the above compound may be "X--CO--O--Z" or "X--O--CO--Z."

In this specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and dispersity (also referred to as molecular weight distribution) (Mw/Mn) of the resin are measured by a GPC (Gel Permeation Chromatography) device (HLC-8120GPC manufactured by Tosoh Corporation). ) by GPC measurement (solvent: tetrahydrofuran, flow rate (sample injection volume): 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 It is defined as a polystyrene conversion value by a detector (Refractive Index Detector).

As used herein, the acid dissociation constant (pKa) represents the pKa in an aqueous solution. , is a calculated value. All pKa values described herein are 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 obtained by molecular orbital calculation. As a specific method for this, there is a method of calculating the H 2 ⁺ dissociation free energy in an aqueous solution based on the thermodynamic cycle. H ⁺ dissociation free energy can be calculated by, for example, DFT (density functional theory), but various other methods have been reported in literature, etc., and are not limited to this. . Note that there are a plurality of software that can implement DFT, and Gaussian16 is an example.

The pKa in the present specification refers to a value obtained by calculating a value based on a database of Hammett's substituent constants and known literature values using Software Package 1, as described above. If it cannot be calculated, a value obtained by Gaussian 16 based on DFT (density functional theory) is adopted.
In addition, pKa in this specification refers to "pKa in aqueous solution" as described above, but when pKa in aqueous solution cannot be calculated, "pKa in dimethyl sulfoxide (DMSO) solution" is adopted. It shall be.

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

In this specification, the solid content is intended to be the component that forms the resist film, and does not include the solvent. In addition, as long as it is a component that forms a resist film, it is regarded as a solid content even if its property is liquid.

[Actinic ray-sensitive or radiation-sensitive resin composition]
The actinic ray-sensitive or radiation-sensitive resin composition (hereinafter also referred to as "resist composition") of the present invention is represented by a repeating unit represented by formula (1) described later and a repeating unit represented by formula (2) described later. It contains a polymer (hereinafter also referred to as "specific polymer") containing a specific repeating unit (hereinafter also referred to as "repeating unit A") selected from the group consisting of repeating units, and a solvent.

The resist composition of the present invention has excellent resolution due to the above constitution.
Although this is not clear in detail, the present inventors presume as follows.
Due to the structure of the repeating unit A, when the specific polymer is irradiated with ionizing radiation such as electron beams and extreme ultraviolet rays and light with short wavelengths such as ultraviolet rays, the main chain is scissionable and the molecular weight is easily reduced. , and its solubility in an organic developer is remarkably low when it is not exposed to light. As a result, the resist film formed from the resist composition of the present invention containing the specific polymer has a high dissolution contrast between the unexposed area and the exposed area, and is considered to have excellent resolution of the formed pattern. .
In addition, as will be described later, the present inventors found that when the resist composition contains a photodecomposable onium salt compound, the interaction between the specific polymer and the photodecomposable onium salt compound causes the unexposed area to It has also been clarified that the dissolution contrast of the exposed area is further increased, and the resolution of the pattern formed as a result is more excellent.

In the following, the better resolution of the pattern formed from the resist composition and/or the better LWR of the pattern formed from the resist composition is also referred to as "the effect of the present invention is better." say.

Below, first, various components contained in the resist composition will be described.

[Specific polymer]
The specific polymer contains a specific repeating unit (repeating unit A) selected from the group consisting of repeating units represented by formula (1) and repeating units represented by formula (2). The specific polymer corresponds to a so-called main chain scission type polymer in which the main chain is cut by the action of exposure to light to cause a decrease in molecular weight. As will be described later, since the main chain scission efficiency is further improved and the effect of the present invention is more excellent, the specific polymer further includes a repeating unit represented by formula (3) (hereinafter "repeating unit B" It is also preferable to include
The repeating unit represented by formula (1) and the repeating unit represented by formula (2) are described below.
<Repeating Unit Represented by Formula (1) and Repeating Unit Represented by Formula (2) (Repeating Unit A)>

In Formula (1), X represents a halogen atom. R ¹ to R ³ each independently represent a hydrogen atom or a substituent. However, at least one of R ¹ and R ² represents an electron-withdrawing group.

In formula (1), the halogen atom represented by X includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like. Among them, a fluorine atom, a chlorine atom, and an iodine atom are preferred from the viewpoint that the effects of the present invention are more excellent, and a chlorine atom is more preferred from the viewpoint that the storage stability of the resist composition is more excellent.

In formula (1), the substituent represented by R ¹ to R ³ is not particularly limited, and examples thereof include the groups exemplified for the substituent W below.
(Substituent W)
Substituent W is, for example, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an aralkyl group, a cyano group, a nitro group, an alkoxy group, an aryloxy group, a silyloxy group, a heterocyclicoxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, primary to tertiary amino group (including anilino group), alkylthio group, arylthio group, heterocyclicthio group, alkyl or arylsulfinyl group, alkyl or arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, aryl or heterocyclic azo group, amide group, sulfonamide group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinyl An amino group, a phosphono group, a silyl group, an acylamino group, a carbamoyl group, a ureido group, a hydroxy group, a carboxy group, a sulfonic acid group, a phosphoric acid group, and the like. In addition, each group described above may further have a substituent (for example, one or more groups among the groups described above), if possible. For example, an alkyl group which may have a substituent is also included as one form of the substituent W.
Further, when the substituent W has carbon atoms, the carbon number of the substituent W is, for example, 1 to 20.
Further, the number of atoms other than hydrogen atoms possessed by the substituent W is, for example, 1-30.

The number of carbon atoms in the alkyl group exemplified for the substituent W is preferably 1-20, more preferably 1-10, and even more preferably 1-6.
Alkyl groups may be linear, branched, or cyclic.
Examples of alkyl groups include linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, t-butyl group, and n-hexyl group, Monocyclic cycloalkyl groups such as cyclopentyl and cyclohexyl groups, and polycyclic cycloalkyl groups such as norbornyl, tetracyclodecanyl, tetracyclododecanyl, and adamantyl groups are included.
In the alkyl group which may have a substituent, the substituent which the alkyl group may have is not particularly limited, and examples thereof include groups exemplified for the substituent W. can contain, for example, a phenolic hydroxyl group, a carboxyl group, a sulfonic acid group, an amide group, and an interactive group (hereinafter referred to as "interactive group") such as a sulfonamide group.
In addition, the said phenolic hydroxyl group intends the hydroxyl group substituted by the ring member atom of the aromatic ring (aromatic-hydrocarbon ring and aromatic heterocycle). The amido group is not particularly limited, but includes, for example, -C(=O)-NHR ^P (R ^P represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms).

The alkyl group portion of the alkoxy group, the alkyl group portion of the aralkyl group, the alkyl group portion of the alkylthio group, the alkyl group portion of the alkylsulfinyl group, and the alkyl portion of the alkylsulfonyl group exemplified for the substituent W are the above alkyl groups. preferable. In addition, an alkoxy group which may have a substituent, an aralkyl group which may have a substituent, an alkylthio group which may have a substituent, an alkylsulfinyl group which may have a substituent, and a substituent In the alkylsulfonyl group optionally having a substituent, the alkoxy group, aralkyl group, alkylthio group, alkylsulfinyl group, and alkylsulfonyl group may have Examples similar to those for substituents can be given.

The alkenyl group exemplified for the substituent W may be linear, branched, or cyclic. The alkenyl group preferably has 2 to 20 carbon atoms. In the alkenyl group which may have a substituent, examples of the substituent which the alkenyl group may have are the same as those of the alkyl group which may have a substituent.
The alkynyl group exemplified for the substituent W may be linear, branched, or cyclic. The alkynyl group preferably has 2 to 20 carbon atoms. In the alkynyl group which may have a substituent, examples of the substituent which the alkynyl group may have are the same as those of the alkyl group which may have a substituent.

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

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

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

The lactone group exemplified for the substituent W is preferably a 5- to 7-membered lactone group, and the 5- to 7-membered lactone ring is condensed with another ring structure to form a bicyclo structure or a spiro structure. is more preferable.
In the optionally substituted lactone group, examples of the substituent which the lactone group may have are the same as those of the optionally substituted alkyl group.

In formula (1), the substituents represented by R ¹ and R ² are, among others, optionally substituted alkyl groups, aryl groups, or heteroaryl groups, or electron-withdrawing groups. is preferred.

In this specification, whether or not the substituents represented by R ¹ and R ² are electron-withdrawing groups is determined by calculating the compound represented by the following formula (1-X) as a model compound. is intended to have an acid dissociation constant pKa value of 9.5 or less. That is, for example, when the relevant substituent is a methoxy ^group , the acid dissociation constant pKa is used to determine whether or not the methoxy group corresponds to an electron-withdrawing group. The method for measuring the acid dissociation constant pKa of the hydroxy group is as described above.

In formula (1-X), R ^e represents a substituent to be measured.

The electron-withdrawing group represented by R ¹ and R ² is preferably a substituent in which the acid dissociation constant pKa of the hydroxy group is 9.0 or less, and 8.5 or less. It is more preferable that it is a substituent that becomes 8.0 or less is more preferable. The lower limit is not particularly limited, and is preferably 4.0 or more, for example.
Specific examples of such electron-withdrawing groups include groups containing C=O bonds, groups containing S=O bonds (e.g., groups containing bonds such as -SO- and -SO ₂ -), Examples include a halogenated alkyl group, a halogenated aryl group, and the like, and among them, a group represented by any one of the following formulas (a) to (c) and a halogenated alkyl group in that the effects of the present invention are more excellent. , or a halogenated aryl group, and more preferably a group represented by any one of the following formulas (a) to (c).

In formulas (a) to (c), R 1 ^X represents a hydrogen atom or a substituent.
The substituent represented by R ^X is not particularly limited, and includes the groups exemplified for the substituent W described above, among which an alkyl group, an aryl group, or a heteroaryl group, which may have a substituent. is preferred, an optionally substituted alkyl group or an aryl group is more preferred, and an optionally substituted alkyl group having 1 to 6 carbon atoms or a phenyl group is even more preferred.
Further, in formulas (a) to (c), * represents a bonding site with the nitrogen atom in formula (1).

As the halogenated alkyl group, a linear or branched alkyl having 1 to 20 carbon atoms (preferably 1 to 10, more preferably 1 to 6) substituted with one or more halogen atoms groups are preferred.
More preferably, the halogenated aryl group is substituted with one or more halogen atoms and has 6 to 15 (preferably 6 to 10) ring member atoms. Examples of the halogenated aryl group include a phenyl group or a naphthyl group substituted with a halogen atom.
The halogenated alkyl group and the halogenated aryl group may have substituents other than halogen atoms (for example, the groups exemplified for the substituent W above).

In the point that the effect of the present invention is more excellent, in the repeating unit represented by formula (1), R ¹ is a hydrogen atom, or an optionally substituted alkyl group, aryl group, or heteroaryl group and R ² preferably represents an electron-withdrawing group, R ¹ represents a hydrogen atom or an optionally substituted alkyl group, aryl group, or heteroaryl group, and R More preferably, ² represents a group represented by any one of formulas (a) to (c). When R ¹ represents an optionally substituted alkyl group or aryl group, the substituent is preferably a substituent other than a halogen atom.

In formula (1), R ³ is preferably a hydrogen atom or an optionally substituted alkyl group, more preferably a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. A hydrogen atom is preferred, and a hydrogen atom is more preferred.

In Formula (2), X represents a halogen atom. ^R4 represents a hydrogen atom or a substituent. L ¹ and L ² each independently represent -CO-, -SO- or -SO ₂ -. ^L3 represents a single bond or a divalent linking group.

In formula (2), the halogen atom represented by X includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like. Among them, an iodine atom is preferable because the effects of the present invention are more excellent.
In formula (2), the substituent represented by R ⁴ is not particularly limited, and examples thereof include the groups exemplified for the substituent W above, among which an optionally substituted alkyl group, An aryl group or a heteroaryl group is preferred, and an optionally substituted alkyl group or aryl group is more preferred.

L ¹ and L ² preferably represent -CO-.
The divalent linking group represented by L ³ is not particularly limited, and examples thereof include -CR ^S1 R ^S2 - and -CR ^S3 R ^S4 -CR ^S5 R ^S6 -.
R ^S1 to R ^S6 each independently represent a hydrogen atom or a substituent. The substituent represented by R ^S1 to R ^S6 is not particularly limited, and examples thereof include the groups exemplified for the substituent W above, preferably an alkyl group optionally having a substituent, and having a substituent An alkyl group having 1 to 6 carbon atoms, which may be R ^S1 to R ^S6 are preferably hydrogen atoms.
L ³ is preferably a single bond or —CR ^S1 R ^S2 —, more preferably a single bond.

The repeating unit A contains at least one repeating unit selected from the group consisting of the following formula (1)-1 and the following formula (2)-1 in that the effect of the present invention is more excellent. is preferred, and it is more preferred to contain a repeating unit represented by the following formula (2)-1.

X and R ¹ in formula (1)-1 have the same meanings as X and R ¹ in formula (1) described above, and the preferred embodiments are also the same.
W in formula (1)-1 represents an electron-withdrawing group represented by either -CO-R ^X or -SO ₂ -R ^X. R ^X represents a hydrogen atom or a substituent. R 1 ^X has the same meaning as R 1 ^X in formulas (a) to (c) above, and preferred embodiments are also the same.

In formula (2)-1, X and R ⁴ have the same meanings as X and R ⁴ in formula (2) above, and the preferred embodiments are also the same.

Specific examples of the monomer constituting the repeating unit A are listed below, but are not limited thereto. In the structures below, "Me" represents a methyl group, and "Ph" represents a phenyl group. Moreover, "5FPh" represents a perfluorophenyl group.
In addition, "pKa" in the table below means that "-CO-R ^X " or "-SO ₂ -R ^X " shown in the table is applied to R ^e in the above formula (1-X). It represents the acid dissociation constant of the hydroxy group in the obtained model compound.

In the specific polymer, the lower limit of the content of the repeating unit A is preferably 10 mol% or more, more preferably 20 mol% or more, and 40 mol% or more, based on the total repeating units. More preferably. The upper limit is 100 mol % or less, preferably 80 mol % or less, more preferably 60 mol % or less, based on all repeating units.

The specific polymer preferably further contains a repeating unit (repeating unit B) represented by formula (3). The repeating unit (repeating unit B) represented by Formula (3) will be described below.
<Repeating Unit Represented by Formula (3) (Repeating Unit B)>

In formula (3), ^R5 represents a hydrogen atom or a hydrocarbon group which may have a substituent.
R ⁵ is preferably a hydrocarbon group which may have a substituent.
The optionally substituted hydrocarbon group represented by R ⁵ includes a linear, branched or cyclic alkyl group which may have a substituent, and a substituted and aryl groups that may be used.
The linear, branched, or cyclic alkyl group represented by R ⁵ which may have a substituent is preferably an alkyl group exemplified as the substituent W, and has a substituent. An alkyl group having 1 to 6 carbon atoms which may be substituted is more preferred, and a methyl group or an ethyl group is even more preferred.
The aryl group which may have a substituent represented by R ⁵ is preferably an aryl group exemplified as the substituent W, more preferably a phenyl group or a naphthyl group which may have a substituent. preferable.

Z has a group represented by -NR ^f R ^g or a substituent in which -CH ₂ - may be substituted with a group selected from the group consisting of -O- and -CO- represents a good hydrocarbon group.

In the group represented by —NR ^f R ^g represented by Z above, R ^f represents a hydrocarbon group which may have a substituent, R ^g may have a hydrogen atom or a substituent represents a good hydrocarbon group. R ^f and R ^g may combine with each other to form a ring. In the optionally substituted hydrocarbon groups represented by R ^f and R ^g , -CH ₂ - is -O-, -CO-, -SO-, and -SO ₂ - It may be substituted with a group selected from the group consisting of
The optionally substituted hydrocarbon groups represented by R ^f and R ^g include linear, branched or cyclic alkyl groups optionally having substituents, and substituted An aryl group optionally having a group and the like can be mentioned.
The linear, branched, or cyclic alkyl group which may have a substituent is preferably an alkyl group exemplified as the substituent W, which may have a substituent. An alkyl group having 1 to 6 carbon atoms is more preferred, and a methyl group or an ethyl group is even more preferred.
The aryl group which may have a substituent is preferably the aryl group exemplified as the substituent W, and more preferably a phenyl group or a naphthyl group which may have a substituent.
Moreover, the ring formed by combining R ^f and R ^g is not particularly limited, and may be either monocyclic or polycyclic. The above ring may contain heteroatoms such as oxygen, nitrogen and sulfur atoms and/or carbonyl carbon as ring member atoms.
The above ring is preferably a 5- or 6-membered alicyclic ring.

The hydrocarbon group, which may be substituted by a group selected from the group consisting of -O- and -CO-, in which -CH ₂ - represented by Z is particularly limited to However, for example, an optionally substituted alkyl group (which may be linear, branched, or cyclic), an optionally substituted aryl group, —OR ⁶ , —COOR ⁷ , or -OCOR ⁸ is preferred. Each of R ⁶ to R ⁸ above may independently have an optionally substituted alkyl group (which may be linear, branched, or cyclic) or may have a substituent represents an aryl group.

Examples of the optionally substituted alkyl group represented by Z and the optionally substituted alkyl group represented by R ⁶ to R ⁸ include the alkyl groups exemplified as the substituent W. is preferred, and an optionally substituted alkyl group having 1 to 6 carbon atoms is more preferred. Examples of the substituent that the alkyl group may have include the groups exemplified as the substituent W, and among them, the interactive group described above is preferable.
The aryl group optionally having substituents represented by Z and the aryl group optionally having substituents represented by R ⁶ to R ⁸ are the aryl groups exemplified as the substituent W. is preferred, and a phenyl group optionally having a substituent is more preferred. Examples of the substituent that the aryl group may have include the groups exemplified as the substituent W, and among them, the interactive group described above is preferable.

As the repeating unit (repeating unit B) represented by formula (3), any one selected from the group consisting of formulas (3)-1 to (3)-4 in that the effects of the present invention are more excellent. It preferably contains one or more repeating units, more preferably contains a repeating unit represented by formula (3)-1, and preferably contains a repeating unit represented by formula (3)-1-1 More preferred.

In formula (3)-1, R ^a represents a hydrocarbon group which may have a substituent.
The hydrocarbon group optionally having substituents represented by R ^a is the same as the hydrocarbon group optionally having substituents represented by R ⁵ in formula (3), and is a preferred embodiment. is the same.

R ^b represents a substituent.
The substituent represented by R ^b is not particularly limited, and includes the groups exemplified as the substituent W, and among these, an interactive group is preferred.
n represents an integer of 0 to 5; n preferably represents an integer of 0 to 3.
m represents 0 or 1;

In formula (3)-2, R ^c and R ^d each independently represent a hydrocarbon group which may have a substituent. In the optionally substituted hydrocarbon group represented by R ^d , —CH ₂ — may be substituted with —CO—.
The hydrocarbon group optionally having substituents represented by R ^c is the same as the hydrocarbon group optionally having substituents represented by R ⁵ in formula (3). is the same.
Examples of the optionally substituted hydrocarbon group represented by R ^d include an optionally substituted alkyl group, an optionally substituted aryl group, and a substituted and an alkylcarbonyl group which may be substituted.
As the alkyl group optionally having substituent(s) and the aryl group optionally having substituent(s) described above, alkyl optionally having substituent(s) represented by R ⁶ to R ⁸ in formula (3) It is the same as the aryl group optionally having a group and a substituent, and the preferred embodiments are also the same.
The alkyl portion of the alkylcarbonyl group optionally having substituents described above is the same as the alkyl group optionally having substituents represented by R ⁶ to R ⁸ in formula (3), and is preferably The mode is also the same.

In formula (3)-3, R ^e represents a hydrocarbon group which may have a substituent.
The hydrocarbon group optionally having substituents represented by ^Re is the same as the hydrocarbon group optionally having substituents represented by R ⁵ in formula (3), and is a preferred embodiment. is the same.
R ^f and R ^g in formula (3)-3 have the same definitions as R ^f and R ^g in the group represented by —NR ^f R ^g represented by Z in formula (3), and are preferred embodiments. is the same.

In formula (3)-4, each R ^h independently represents a hydrocarbon group which may have a substituent. R ⁱ represents a hydrogen atom or a hydrocarbon group which may have a substituent.
The optionally substituted hydrocarbon group represented by R ^h is the same as the optionally substituted hydrocarbon group represented by R ⁵ in formula (3), and is a preferred embodiment. is the same.
Examples of the optionally substituted hydrocarbon group represented by R ⁱ include an optionally substituted alkyl group (which may be linear, branched, or cyclic), Alternatively, an aryl group optionally having a substituent may be used. As the alkyl group optionally having substituent(s) and the aryl group optionally having substituent(s) described above, alkyl optionally having substituent(s) represented by R ⁶ to R ⁸ in formula (3) It is the same as the aryl group optionally having a group and a substituent, and the preferred embodiments are also the same.

The repeating unit (repeating unit B) represented by formula (3) is derived from a monomer selected from the group consisting of α-methylstyrenes, isopropenyl ethers, isopropenylamines, and methacrylic acid esters. It is also preferred that it is a repeating unit.

In formula (3)-1-1, R ^a represents a hydrocarbon group which may have a substituent. R ^b represents a substituent. n represents an integer of 0 to 5;
R ^a , R ^b , and n in formula (3)-1-1 have the same meanings as R ^a , R ^b , and n in formula (3)-1, and preferred embodiments are also the same.

Specific examples of the monomer constituting the repeating unit B are given below, but are not limited thereto.

In the specific polymer, the total content of the repeating unit A and the repeating unit B is preferably 90 mol% or more, more preferably 95 mol% or more, relative to all repeating units. In addition, as an upper limit, 100 mol% or less is preferable.

In the specific polymer, the repeating unit A and the repeating unit B may be in any form such as a random copolymer, a block copolymer, and an alternating copolymer (ABAB . . . ). However, among others, it is preferably an alternating copolymer.
As a preferred embodiment of the specific polymer, the ratio of the alternating copolymer in the specific polymer is 90% by mass or more (preferably 100% by mass or more) based on the total mass of the specific polymer. Aspects are also included.

In the specific polymer, the content of the repeating unit (repeating unit B) represented by the above formula (3) is preferably 10 mol% or more, more preferably 20 mol% or more, based on the total repeating units. is more preferable, and 40 mol % or more is even more preferable. The upper limit is less than 100 mol %, preferably 80 mol % or less, more preferably 60 mol % or less, relative to all repeating units.

<Other repeating units>
The specific polymer may contain repeating units other than the repeating units described above as long as the effects of the present invention are not impaired.
Other repeating units include, for example, repeating units derived from α-haloacrylates.

A specific polymer can be synthesized according to a conventional method (for example, radical polymerization).
The lower limit of the weight-average molecular weight of the specific polymer is preferably 1,000 or more, more preferably 2,500 or more, and even more preferably 30,000 or more, as a polystyrene-equivalent value by GPC method. The upper limit is preferably 200,000 or less, more preferably 150,000 or less, still more preferably 80,000 or less, and particularly preferably 65,000 or less. When the weight-average molecular weight is within the above numerical range, the effects of the present invention are more excellent, and the deterioration of heat resistance and dry etching resistance can be further suppressed. In addition, it is possible to further suppress the deterioration of the developability and the deterioration of the film formability due to an increase in viscosity.
The degree of dispersion (molecular weight distribution) of the specific polymer is usually 1.0 to 5.0, preferably 1.0 to 3.0, more preferably 1.2 to 3.0, and 1.2 to 2.0. 5 is more preferred. When the degree of dispersion is within the above range, the resolution and resist shape are better.

Further, as the specific polymer, the repeating unit A of the specific polymer is a repeating unit represented by the formula (1) (provided that the electron-withdrawing group is 8.5 or less case) and any one or more repeating units represented by formula (2), it preferably satisfies any one or more of the following conditions S1 to S3.
(S1) The specific polymer contains a repeating unit represented by formula (2)-1.
(S2) The specific polymer contains a repeating unit represented by formula (3)-1 (preferably formula (3)-1-1).
(S3) The weight average molecular weight of the specific polymer is 30,000 or more.

In the resist composition, the content of the specific polymer is preferably 50.0 to 100.0% by mass, more preferably 50.0 to 99.9% by mass, based on the total solid content of the composition. 0 to 99.0% by mass is more preferable, and 70.0 to 99.0% by mass is particularly preferable.
Also, the specific polymer may be used alone or in combination. When two or more are used, the total content is preferably within the range of the preferred content.

〔solvent〕
The resist composition contains a solvent.
Solvent consists of (M1) propylene glycol monoalkyl ether carboxylate and (M2) propylene glycol monoalkyl ether, lactate, acetate, alkoxypropionate, linear ketone, cyclic ketone, lactone, and alkylene carbonate. It preferably contains at least one selected from the group. This solvent may further contain components other than components (M1) and (M2).

When such a solvent and a specific polymer are used in combination, the coatability of the resist composition is improved and a pattern with few development defects can be easily formed. The reason for this is that these solvents have an excellent balance of the solubility, boiling point, and viscosity of the specific polymer, so that the resist film, which is the composition film of the resist composition, has an uneven thickness and the occurrence of deposits during spin coating. It is presumed that this is due to the ability to suppress

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

As the component (M2), the following are preferred.
As the propylene glycol monoalkyl ether, propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether are preferred.
Ethyl lactate, butyl lactate, or propyl lactate is preferred as the lactate ester.
Preferred acetic acid esters are methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, isoamyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate and 3-methoxybutyl acetate.
Also preferred is butyl butyrate.
The alkoxypropionate is preferably methyl 3-methoxypropionate (MMP) or ethyl 3-ethoxypropionate (EEP).
Chain ketones include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, phenylacetone, methyl ethyl ketone, and methyl isobutyl. Ketones, acetylacetone, acetonylacetone, ionones, diacetonyl alcohol, acetylcarbinol, acetophenone, methylnaphthylketone or methylamylketone are preferred.
Preferred cyclic ketones are methylcyclohexanone, isophorone, and cyclohexanone.
As the lactone, γ-butyrolactone is preferred.
Propylene carbonate is preferred as the alkylene carbonate.

Propylene glycol monomethyl ether (PGME), ethyl lactate, ethyl 3-ethoxypropionate, methyl amyl ketone, cyclohexanone, butyl acetate, pentyl acetate, γ-butyrolactone, or propylene carbonate are more preferable as component (M2).

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

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

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

When the solvent contains both the component (M1) and the component (M2), the mass ratio of the component (M1) to the component (M2) shall be, for example, 99/1 or less.

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

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

[Other ingredients]
The resist composition may contain components other than the specific polymer and solvent.
Other components are not particularly limited, and include, for example, photodecomposable onium salt compounds and surfactants.

<Photodegradable onium salt compound>
The resist composition preferably contains a compound having an onium salt structure (photodegradable onium salt compound) that generates an acid upon exposure to actinic rays or radiation.
When the resist composition contains a photodegradable onium salt compound, in the unexposed portion, the specific polymer is photodecomposed via the interactive group that may be contained in the specific polymer and the nitrogen atom site of the repeating unit A. Easy to aggregate with type onium salt compounds. On the other hand, when exposed to light, the aggregate structure can be released by cleavage of the photodegradable onium salt compound. That is, due to the above action, the dissolution contrast in the unexposed portion and the exposed portion of the resist film is further increased, and the effect of the present invention tends to be more excellent.
When the resist composition contains a photodegradable onium salt compound, the specific polymer contained in the resist composition preferably has an interactive group. The interactive group includes the phenolic hydroxyl group, carboxyl group, sulfonic acid group, amide group, sulfonamide group, and the like described above.

A photodegradable onium salt compound is a compound that has at least one salt structure site composed of an anion site and a cation site, and that decomposes upon exposure to generate an acid (preferably an organic acid). preferable.
The above-mentioned salt structure portion of the photodegradable onium salt compound is easily decomposed by exposure to light and has excellent organic acid production properties. preferably
The salt structure portion may be a part or the whole of the photodecomposable onium salt compound. The case where the above-mentioned salt structure site is a part of the photodegradable onium salt compound corresponds to, for example, a structure in which two or more salt structure sites are linked, such as the photodegradable onium salt PG2 described later. do.
The number of salt structure sites in the photodecomposable onium salt is not particularly limited, but is preferably 1-10, more preferably 1-6, more preferably 1-3.

Examples of the organic acid generated from the photodegradable onium salt compound by the action of exposure include, for example, sulfonic acid (aliphatic sulfonic acid, aromatic sulfonic acid, camphorsulfonic acid, etc.), carboxylic acid (aliphatic carboxylic acid, aromatic carboxylic acid, aralkylcarboxylic acid, etc.), carbonylsulfonylimidic acid, bis(alkylsulfonyl)imidic acid, tris(alkylsulfonyl)methide acid and the like.
Moreover, the organic acid generated from the photodegradable onium salt compound by the action of exposure may be a polyvalent acid having two or more acid groups. For example, when the photodegradable onium salt compound is a photodegradable onium salt compound PG2 described later, the organic acid generated by decomposition of the photodegradable onium salt compound by exposure becomes a polyvalent acid having two or more acid groups. .

In the photodegradable onium salt compound, the cation site constituting the salt structure site is preferably an organic cation site, and among them, an organic cation (cation (ZaI)) represented by the formula (ZaI) described later. Or an organic cation represented by the formula (ZaII) (cation (ZaII)) is preferred.

(Photodegradable onium salt compound PG1)
An example of a preferred embodiment of the photodegradable onium salt compound is an onium salt compound represented by “M ⁺ X ⁻ ” that generates an organic acid upon exposure (hereinafter “photodegradable onium salt compound PG1” Also called).
In the compound represented by “M ⁺ X ⁻ ”, M ⁺ represents an organic cation and X ⁻ represents an organic anion.
The photodegradable onium salt compound PG1 will be described below.

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

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

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

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

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 having an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Heterocyclic structures include pyrrole residues, furan residues, thiophene residues, indole residues, benzofuran residues, benzothiophene residues, and the like. 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 optionally possessed by the arylsulfonium cation is a linear alkyl group having 1 to 15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, or 3 to 15 carbon atoms. is preferred, and for example, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, t-butyl group, cyclopropyl group, cyclobutyl group, cyclohexyl group and the like are more preferred.

The substituents that the aryl group, alkyl group and cycloalkyl group of R ²⁰¹ to R ²⁰³ may have are each independently an alkyl group (eg, having 1 to 15 carbon atoms) and a cycloalkyl group (eg, having 1 to 15 carbon atoms). 3 to 15), aryl groups (eg, 6 to 14 carbon atoms), alkoxy groups (eg, 1 to 15 carbon atoms), cycloalkylalkoxy groups (eg, 1 to 15 carbon atoms), halogen atoms (eg, fluorine, iodine), hydroxyl groups , a carboxyl group, an ester group, a sulfinyl group, a sulfonyl group, an alkylthio group, a phenylthio group, and the like.
The above substituents may further have a substituent if possible. For example, the above alkyl group may have a halogen atom as a substituent to form a halogenated alkyl group such as a trifluoromethyl group. preferable.

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

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

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

In formula (ZaI-3b),
R _1c to R _5c each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, or a hydroxyl group , represents 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.

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 combine with each other to form a ring. The rings may each independently contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond.
Examples of the ring include aromatic or non-aromatic hydrocarbon rings, aromatic or non-aromatic hetero rings, and polycyclic condensed rings in which two or more of these rings are combined. The ring includes a 3- to 10-membered ring, preferably a 4- to 8-membered ring, more preferably a 5- or 6-membered ring.

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

R _1c to R _5c , R _6c , R _7c , R _x , R _y , and two or _more of R _1c to R 5c , R _5c and R _6c , R _6c and R _7c , R _5c and R _x , and the ring formed by combining R _x and R _y with each other may have a substituent.

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

In formula (ZaI-4b),
l represents an integer of 0 to 2;
r represents an integer of 0 to 8;
R ₁₃ is a hydrogen atom, a halogen atom (e.g., fluorine atom, 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 (cycloalkyl may be the group itself, or may be a group partially containing a cycloalkyl group). These groups may have a substituent.
R ₁₄ is a hydroxyl group, a halogen atom (e.g., fluorine atom, 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 cycloalkyl group (either a cycloalkyl group itself or a group partially containing a cycloalkyl group). These groups may have a substituent. Each of R ₁₄ independently represents the above group such as a hydroxyl group when a plurality of R 14 are present.
Each R ₁₅ independently represents an alkyl group, a cycloalkyl group, or a naphthyl group. Two R ₁₅ may be joined together to form a ring. When two R ₁₅ are combined to form a ring, the ring skeleton may contain a heteroatom such as an oxygen atom or a nitrogen atom. In one aspect, two R ₁₅ are alkylene groups, preferably joined together to form a ring structure. The ring formed by combining the alkyl group, the cycloalkyl group, the naphthyl group, and the two R ₁₅ groups may have a substituent.

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

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 for R ²⁰⁴ and R ²⁰⁵ is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group for R ²⁰⁴ and R ²⁰⁵ may be an aryl group having a heterocyclic ring having an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Skeletons of heterocyclic aryl groups include, for example, pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene.
The alkyl group and cycloalkyl group for R ²⁰⁴ and R ²⁰⁵ include a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, or pentyl group), or a cycloalkyl group having 3 to 10 carbon atoms (eg, cyclopentyl group, cyclohexyl group, or norbornyl group).

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

Specific examples of organic cations represented by M ⁺ are shown below, but the present invention is not limited thereto.

The organic anion represented by X ^{1 −} in the photodecomposable onium salt compound PG1 is preferably a non-nucleophilic anion (an anion having a remarkably low ability to cause a nucleophilic reaction).
Examples of non-nucleophilic anions include sulfonate anions (aliphatic sulfonate anions, aromatic sulfonate anions, camphorsulfonate anions, etc.), carboxylate anions (aliphatic carboxylate anions, aromatic carboxylate anions, , and aralkylcarboxylate anions), sulfonylimide anions, bis(alkylsulfonyl)imide anions, tris(alkylsulfonyl)methide anions, and the like.

As the organic anion, for example, an organic anion represented by the following formula (DA) is also preferable.

In formula (DA), A ^31- represents an anionic group. R _a1 represents a hydrogen atom or a monovalent organic group. L _a1 represents a single bond or a divalent linking group.

A ^31- represents an anionic group. The anionic group represented by A ^31- is not particularly limited, but is preferably, for example, a group selected from the group consisting of groups represented by formulas (B-1) to (B-14). , among others, formula (B-1), formula (B-2), formula (B-3), formula (B-4), formula (B-5), formula (B-6), formula (B- 10), formula (B-12), formula (B-13), or formula (B-14) are more preferred.

* ^-O- Formula (B-14)

In formulas (B-1) to (B-14), * represents a bonding position.
In formulas (B-1) to (B-5) and formula (B-12), each R ^X1 independently represents a monovalent organic group.
In formulas (B-7) and (B-11), each R ^{1 X2} independently represents a hydrogen atom or a substituent other than a fluorine atom and a perfluoroalkyl group. Two R 1 ^X2 in formula (B-7) may be the same or different.
In formula (B-8), R ^{1 XF1} represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group. However, at least one of the two R ^XF1 represents a fluorine atom or a perfluoroalkyl group. Two R ^{1 XF1} in formula (B-8) may be the same or different.
In formula (B-9), R 1 ^X3 represents a hydrogen atom, a halogen atom, or a monovalent organic group. n1 represents an integer of 0-4. When n1 represents an integer of 2 to 4, multiple R ^{1 X3} may be the same or different.
In formula (B-10), R ^{1 XF2} represents a fluorine atom or a perfluoroalkyl group.
The partner that bonds to the bonding position represented by * in formula (B-14) is preferably a phenylene group that may have a substituent. A halogen atom etc. are mentioned as a substituent which the said phenylene group may have.

In formulas (B-1) to (B-5) and formula (B-12), each R ^X1 independently represents a monovalent organic group.
R ^X1 is an alkyl group (either linear or branched, preferably having 1 to 15 carbon atoms), a cycloalkyl group (either monocyclic or polycyclic, preferably having 3 to 20 carbon atoms). ), or an aryl group (which may be monocyclic or polycyclic, preferably having 6 to 20 carbon atoms). Further, the above group represented by R ^X1 may have a substituent.
In formula (B-5), the atom directly bonded to N- in R ^{1 X1} is preferably neither a carbon atom in -CO- nor a sulfur atom in -SO ₂ -.

The cycloalkyl group in R ^X1 may be monocyclic or polycyclic.
The cycloalkyl group for R ^X1 includes, for example, a norbornyl group and an adamantyl group.

The substituent that the cycloalkyl group in R ^{1 X1} may have is not particularly limited, but an alkyl group (either linear or branched, preferably having 1 to 5 carbon atoms) is preferred. One or more carbon atoms that are ring member atoms of the cycloalkyl group in R ^X1 may be replaced with a carbonyl carbon atom.

The number of carbon atoms in the alkyl group in R ^X1 is preferably 1-10, more preferably 1-5.
The substituent that the alkyl group in R ^X1 may have is not particularly limited, but is preferably, for example, a cycloalkyl group, a fluorine atom, or a cyano group.
Examples of the cycloalkyl group as the substituent include the cycloalkyl groups described in the case where R ^{1 X1} is a cycloalkyl group.
When the alkyl group in R ^X1 has a fluorine atom as the substituent, the alkyl group may be a perfluoroalkyl group.
In addition, one or more —CH ₂ — of the alkyl group in R ^X1 may be substituted with a carbonyl group.

The aryl group for R ^X1 is preferably a benzene ring group.
The substituent that the aryl group in R ^X1 may have is not particularly limited, but an alkyl group, a fluorine atom, or a cyano group is preferable. Examples of the alkyl group as the substituent include the alkyl groups described in the case where R ^{1 X1} is an alkyl group.

In formulas (B-7) and (B-11), each R ^{1 X2} is independently a hydrogen atom, or a substituent other than a fluorine atom and a perfluoroalkyl group (e.g., an alkyl group containing no fluorine atom and a fluorine atom includes a cycloalkyl group that does not contain ). Two R 1 ^X2 in formula (B-7) may be the same or different.

In formula (B-8), R ^{1 XF1} represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group. However, at least one of the plurality of R ^XF1 represents a fluorine atom or a perfluoroalkyl group. Two R ^{1 XF1} in formula (B-8) may be the same or different. The perfluoroalkyl group represented by R ^{1 XF1} preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and still more preferably 1 to 6 carbon atoms.

In formula (B-9), R 1 ^X3 represents a hydrogen atom, a halogen atom, or a monovalent organic group. The halogen atom as R ^{1 X3} includes, for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred.
The monovalent organic group as R ^X3 is the same as the monovalent organic group described as R ^X1 .
n1 represents an integer of 0-4.
n1 is preferably an integer of 0 to 2, preferably 0 or 1. When n1 represents an integer of 2 to 4, multiple R ^{1 X3} may be the same or different.

In formula (B-10), R ^{1 XF2} represents a fluorine atom or a perfluoroalkyl group.
The perfluoroalkyl group represented by R ^{1 XF2} preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and still more preferably 1 to 6 carbon atoms.

In formula (DA), the monovalent organic group represented by R _a1 is not particularly limited, but generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _a1 is preferably an alkyl group, a cycloalkyl group, or an aryl group.

The alkyl group may be linear or branched, preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and still more preferably an alkyl group having 1 to 10 carbon atoms.
The cycloalkyl group may be monocyclic or polycyclic, preferably a cycloalkyl group having 3 to 20 carbon atoms, more preferably a cycloalkyl group having 3 to 15 carbon atoms, and further a cycloalkyl group having 3 to 10 carbon atoms. preferable.
The aryl group may be monocyclic or polycyclic, preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms.

The cycloalkyl group may contain heteroatoms as ring member atoms.
Examples of heteroatoms include, but are not limited to, nitrogen atoms, oxygen atoms, and the like.
The cycloalkyl group may also contain a carbonyl bond (>C=O) as a ring member atom.
The above alkyl group, cycloalkyl group and aryl group may further have a substituent.

The divalent linking group as L _a1 is not particularly limited, but includes an alkylene group, a cycloalkylene group, an aromatic group, —O—, —CO—, —COO—, and a group formed by combining two or more of these. represent.
The alkylene group may be linear or branched and preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms.
The cycloalkylene group may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms.
The aromatic group is a divalent aromatic group, preferably an aromatic group having 6 to 20 carbon atoms, more preferably an aromatic group having 6 to 15 carbon atoms.
The aromatic ring constituting the aromatic group is not particularly limited, but examples include aromatic rings having 6 to 20 carbon atoms, and specific examples include benzene ring, naphthalene ring, anthracene ring, and thiophene ring. . The aromatic ring constituting the aromatic group is preferably a benzene ring or a naphthalene ring, more preferably a benzene ring.
The alkylene group, cycloalkylene group, and aromatic group may further have a substituent, and the substituent is preferably a halogen atom.
In addition, A ^31- and R _a1 may combine with each other to form a ring.

Examples of the photodegradable onium salt compound PG1 include, for example, paragraphs [0135] to [0171] of WO2018/193954, paragraphs [0077] to [0116] of WO2020/066824, WO2017/ It is also preferable to use the photoacid generators disclosed in paragraphs [0018] to [0075] and [0334] to [0335] of JP-A-154345.

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

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

<<Compound (I)>>
Compound (I) is a compound having one or more structural moieties X shown below and one or more structural moieties Y shown below, wherein the first acidic It is a compound that generates an acid containing a site and a second acidic site described below derived from the structural site Y described below.
Structural site X: Structural site consisting of an anionic site A ₁ ⁻ and a cation site M ₁ ⁺ and forming a first acidic site represented by HA ₁ upon exposure to actinic rays or radiation Structural site Y: Anionic site A A structural moiety consisting of ₂ ⁻ and a cationic moiety M ₂ ⁺ and forming a second acidic site represented by HA ₂ upon exposure to actinic rays or radiation provided that compound (I) satisfies condition I below.

Condition I: A compound PI obtained by replacing the cation site M ₁ ⁺ in the structural site X and the cation site M ₂ ⁺ in the structural site Y in the compound (I) with H ⁺ in the structural site X and an acid dissociation constant a1 derived from the acidic site represented by HA ₁ obtained by replacing the cation site M 1 ⁺ with H ⁺ , and replacing the cation site M ₂ ⁺ in the structural site _Y with H ⁺ It has an acid dissociation constant a2 derived from the acidic site represented by _HA2 , and the acid dissociation constant a2 is greater than the acid dissociation constant a1.
The above compound PI corresponds to an acid generated when compound (I) is irradiated with actinic rays or radiation.

When compound (I) has two or more structural moieties X, each structural moiety X may be the same or different. Two or more of A ₁ ⁻ and two or more of M ₁ ⁺ may be the same or different.
In compound (I), A ₁ ⁻ and A ₂ ⁻ , and M ₁ ⁺ and M ₂ ⁺ may be the same or different, but A 1 ⁻ and A ₂ − may be the same or different. Each A ₂ ^- is preferably different.

The anion site A ₁ ^- and the anion site A ₂ ^- are structural sites containing negatively charged atoms or atomic groups, for example, formulas (AA-1) to (AA-3) and formula (BB -1) to (BB-6). In formulas (AA-1) to (AA-3) and formulas (BB-1) to (BB-6) below, * represents a bonding position. ^RA represents a monovalent organic group. The monovalent organic group represented by ^RA includes a cyano group, a trifluoromethyl group, a methanesulfonyl group, and the like.

Moreover, the cation site M ₁ ⁺ and the cation site M ₂ ⁺ are structural sites containing positively charged atoms or atomic groups, and examples thereof include monovalent organic cations. Although the organic cation is not particularly limited, the organic cation represented by the formula (ZaI) (cation (ZaI)) or the organic cation represented by the formula (ZaII) (cation (ZaII)) is preferable.

<<Compound (II)>>
Compound (II) is a compound having two or more of the above structural moieties X and one or more of the following structural moieties Z, wherein the first acidic It is a compound that generates an acid containing two or more sites and the structural site Z described above.
Structural site Z: nonionic site capable of neutralizing acid

The compound (II) is a compound PII (acid) having an acidic site represented by HA ₁ in which the cation site M ₁ ⁺ in the structural site X is replaced with H ⁺ by irradiation with actinic rays or radiation. can occur. In other words, compound PII represents a compound having an acidic site represented by HA ₁ above and structural site Z, which is a nonionic site capable of neutralizing acid.
The definition of structural site X and the definitions of A ₁ ^- and M ₁ ⁺ in compound (II) are the same as the definition of structural site X in compound (I) described above, and A ₁ ^- and M ₁ ⁺ is synonymous with the definition of and the preferred embodiment is also the same.
Moreover, the two or more structural moieties X may be the same or different. Two or more of A ₁ ⁻ and two or more of M ₁ ⁺ may be the same or different.

The acid-neutralizable nonionic site in structural site Z is not particularly limited, and for example, a site containing a group capable of electrostatically interacting with protons or a functional group having electrons is preferable. .
As a group capable of electrostatically interacting with protons or a functional group having electrons, a functional group having a macrocyclic structure such as a cyclic polyether, or a nitrogen atom having a lone pair of electrons that does not contribute to π conjugation is used. a functional group having a A nitrogen atom having a lone pair of electrons that does not contribute to π-conjugation is, for example, a nitrogen atom having a partial structure represented by the following formula.

Partial structures of functional groups having electrons or groups capable of electrostatically interacting with protons include, for example, a crown ether structure, an azacrown ether structure, a primary to tertiary amine structure, a pyridine structure, an imidazole structure, and a pyrazine structure. etc., among which primary to tertiary amine structures are preferred.

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

As the photodegradable onium salt compound PG2, compounds exemplified in paragraphs [0023] to [0095] of International Publication No. 2020/158313 can be cited.

When the resist composition contains a photodegradable onium salt compound, the content is not particularly limited, but is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, based on the total solid content of the composition. Preferably, 5.0% by mass or more is more preferable. Moreover, the content is preferably 40.0% by mass or less, more preferably 30.0% by mass or less.
The photodegradable onium salt compounds may be used singly or in combination of two or more. When two or more are used, the total content is preferably within the range of the preferred content.

<<Surfactant>>
The resist composition may contain a surfactant. When a surfactant is contained, the adhesion is better and a pattern with fewer development defects can be formed.
The surfactant is preferably a fluorine-based and/or silicon-based surfactant.
Fluorinated and/or silicon-based surfactants include surfactants disclosed in paragraphs [0218] and [0219] of WO2018/193954.

One type of these surfactants may be used alone, or two or more types may be used.

When the resist composition contains a surfactant, the content of the surfactant is preferably 0.0001 to 2% by mass, more preferably 0.0005 to 1% by mass, based on the total solid content of the composition.

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

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

A method of forming a resist film on a substrate using a resist composition includes, for example, a method of coating the substrate with the resist composition.
In addition, it is preferable to filter the resist composition before application, if necessary. The pore size of the filter is preferably 0.1 µm or less, more preferably 0.05 µm or less, and even more preferably 0.03 µm or less. Moreover, the filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

The resist composition can be applied onto substrates such as those used in the manufacture of integrated circuit devices (eg, silicon, silicon dioxide coatings) by a suitable coating method such as a spinner or coater. The coating method is preferably spin coating using a spinner. The rotation speed for spin coating using a spinner is preferably 1000 to 3000 rpm.
After coating the resist composition, the substrate may be dried to form a resist film. If necessary, various base films (inorganic film, organic film, antireflection film) may be formed under the resist film.

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

Although the film thickness of the resist film is not particularly limited, it is preferably 10 to 120 nm from the viewpoint of forming fine patterns with higher precision. In particular, when EUV exposure is used, the film thickness of the resist film is more preferably 10 to 65 nm, and even more preferably 15 to 50 nm. In the case of ArF liquid immersion exposure, the film thickness of the resist film is more preferably 10 to 120 nm, still more preferably 15 to 90 nm.

A topcoat composition may be used to form a topcoat on the upper layer of the resist film.
It is preferable that the topcoat composition does not mix with the resist film and can be uniformly coated on the upper layer of the resist film. The topcoat is not particularly limited, and a conventionally known topcoat can be formed by a conventionally known method. can be formed.
For example, it is preferable to form a top coat containing a basic compound as described in JP-A-2013-061648 on the resist film. Specific examples of basic compounds that the topcoat may contain include basic compounds that the resist composition may contain.
Also, the topcoat 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.
Examples of the exposure method include a method of irradiating the formed resist film with actinic rays or radiation through a predetermined mask.
Actinic rays or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, and electron beams, preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 -200 nm wavelength deep UV light, specifically KrF excimer laser (248 nm), ArF excimer laser (193 nm), _F2 excimer laser (157 nm), EUV (13 nm), X-rays, and electron beams .

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

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

Examples of the development method include a method in which the substrate is immersed in a tank filled with a developer for a certain period of time (dip method), and a method in which the developer is piled up on the surface of the substrate by surface tension and remains stationary for a certain period of time for development (paddle method). ), a method of spraying the developer onto the surface of the substrate (spray method), and a method of continuously ejecting the developer while scanning the developer ejection nozzle at a constant speed onto the substrate rotating at a constant speed (dynamic dispensing method). is mentioned.
Further, after the step of developing, a step of stopping development may be performed while replacing the solvent with another solvent.
The development time is not particularly limited as long as the resin in the unexposed area is sufficiently dissolved, and is preferably 10 to 300 seconds, more preferably 20 to 120 seconds.
The temperature of the developer is preferably 0 to 50°C, more preferably 15 to 35°C.

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

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

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

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

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

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

Various materials used in the resist composition and the pattern forming method of the present invention (e.g., solvent, developer, rinse, composition for forming an antireflection film, composition for forming a top coat, etc.) contain impurities such as metals. preferably does not contain The content of impurities contained in these materials is preferably 1 mass ppm or less, more preferably 10 mass ppb or less, still more preferably 100 mass ppt or less, particularly preferably 10 mass ppt or less, and most preferably 1 mass ppt 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, Zn, and the like.

　An example of a 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 WO2020/004306.

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

In addition to filter filtration, impurities may be removed with an adsorbent, or filter filtration and adsorbent may be used in combination. As the adsorbent, known adsorbents can be used. For example, inorganic adsorbents such as silica gel and zeolite, and organic adsorbents such as activated carbon can be used. In order to reduce impurities such as metals contained in the various materials described above, it is necessary to prevent metal impurities from entering during the manufacturing process. Whether the metal impurities are sufficiently removed from the manufacturing equipment can be confirmed by measuring the content of the metal component contained in the cleaning liquid used for cleaning the manufacturing equipment. The content of the metal component contained in the cleaning liquid after use is preferably 100 mass ppt (parts per trillion) or less, more preferably 10 mass ppt or less, and even more preferably 1 mass ppt or less.

Conductive compounds are added to organic treatment liquids such as rinsing liquids in order to prevent damage to chemical piping and various parts (filters, O-rings, tubes, etc.) due to electrostatic charging and subsequent electrostatic discharge. You may The conductive compound is not particularly limited, and examples thereof include methanol. The amount added is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, from the viewpoint of maintaining preferable developing properties or rinsing properties.
Examples of chemical pipes include SUS (stainless steel), or antistatic polyethylene, polypropylene, or various pipes coated with fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.). can be used. Antistatic treated polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.) can also be used for filters and O-rings.

[Method for manufacturing electronic device]
The present invention also relates to an electronic device manufacturing method including the pattern forming method described above, and an electronic device manufactured by this manufacturing method.
The electronic device of the present invention is preferably mounted in electric/electronic equipment (household appliances, OA (Office Automation), media-related equipment, optical equipment, communication equipment, etc.).

[Specific polymer]
The present invention also relates to a polymer (specific polymer) containing a repeating unit represented by either formula (1) or (2). The specific polymer is as described above. That is, it includes specific repeating units selected from the group consisting of repeating units represented by formula (1) and repeating units represented by formula (2).
The specific polymer can be used as a so-called main chain scission type polymer.

The present invention will be described in more detail below based on examples. Materials, usage amounts, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed to be limited by the examples shown below.

[Raw material monomer synthesis]
Synthesized monomers were used as raw material monomers for "repeating unit 1" in the polymers (A-1 to A-25) described later. The procedure for synthesizing the monomer C-15 (3-Chloro-1-phenyl-1H-pyrrole-2,5-dione) will be described below as an example.
(1) Synthesis of 3-Bromo-1-phenyl-1H-pyrrole-2,5-dione

N-phenylmaleimide (17.3 g) was added to dichloroethane (1,2-DCE, 100 ml) to obtain a mixed solution. Bromine (17.56 g) was added dropwise to the resulting mixture at room temperature. After completion of the dropwise addition, the mixture was heated to reflux for 1 hour. After refluxing, dichloroethane was distilled off with an evaporator, then tetrahydrofuran (THF, 300 ml) was added to dissolve the contents, and triethylamine (21.23 g) was added dropwise under ice water. After completion of dropping, the mixture was heated to room temperature and reacted for 2 hours, then the reaction was quenched with an aqueous ammonium chloride solution (300 ml), and the THF layer was recovered using a separating funnel. The recovered THF layer was concentrated by an evaporator, and the concentrate was reslurried with methanol (100 ml) and filtered to obtain the desired product, 3-Bromo-1-phenyl-1H-pyrrole-2,5-dione. (10.2 g yield, 40.5% yield).

(2) Synthesis of 3-Chloro-1-phenyl-1H-pyrrole-2,5-dione

The obtained 3-Bromo-1-phenyl-1H-pyrrole-2,5-dione (1.19 g) was added to acetone (30 ml) and further treated with tetrabutylammonium chloride (6.27 g) at room temperature. was added to obtain a mixture. The resulting mixture was then reacted under reflux for 1 hour. After refluxing, reprecipitation was performed with 100 ml of water, and the obtained powder was reslurried with methanol (30 ml) and filtered to obtain the desired product, 3-Chloro-1-phenyl-1H-pyrrole-2. ,5-dione was obtained (0.78 g, 79.5% yield).

Compound (C-15):
¹ H NMR(CDCl ₃ ): δ = 7.51-7.44 (m, 2H), 7.43-7.30 (m, 3H), 6.8 (s, 1H)

[Various Components of Actinic Ray-Sensitive or Radiation-Sensitive Resin Composition]
[Polymer]
The polymers (A-1 to A-25 and RA-1) shown in Table 15 were synthesized by known methods. Polymer RA-1 corresponds to a comparative polymer.
Table 14 shows the compositions of the polymers A-1 to A-25 and RA-1 (raw material monomer, composition ratio of repeating units (mol% ratio), weight average molecular weight (Mw), and degree of dispersion (Mw/Mn)). indicates The weight average molecular weight (Mw) and dispersion degree (Mw/Mn) of the polymers A-1 to A-25 and RA-1 were measured by GPC (carrier: tetrahydrofuran (THF)) (in terms of polystyrene ). Also, the composition ratio (mol% ratio) of the polymer was measured by ¹³ C-NMR (Nuclear Magnetic Resonance).

The structure of each raw material monomer in Table 14 above is as follows.
In the polymers A-1 to A-25, the number of each raw material monomer shown in the "repeating unit 1" column is the upper part as a specific example of the repeating unit represented by either formula (1) or formula (2). It corresponds to the number of the monomer indicated in the part.
Further, in the polymer RA-1, the structure of the raw material monomer (H-3) shown in the "repeating unit 1" column is as follows.

Also, the structures of the raw material monomers (M-1 to M-7) shown in the "Repeating unit 2" column are as follows.

[Photodegradable onium salt compound]
The structures of the photodegradable onium salt compounds (PAG-1 to PAG-3) shown in Table 15 are shown below.

[Surfactant]
The surfactants shown in Table 15 are shown below.
H-1: Megafac F176 (manufactured by DIC Corporation, fluorine-based surfactant)
〔solvent〕
The solvents shown in Table 15 are shown below.
G-1: Propylene glycol monomethyl ether acetate (PGMEA)
G-2: Propylene glycol monomethyl ether (PGME)
G-3: Propylene glycol monoethyl ether (PGEE)
G-4: Cyclohexanone G-5: Ethyl lactate G-6: γ-butyrolactone

[Preparation of actinic ray-sensitive or radiation-sensitive resin composition]
Each component other than the solvent shown in Table 15 was mixed so that the solid content concentration was 1.3% by mass. Then, the resulting mixture was filtered through a polyethylene filter having a pore size of 0.03 μm to prepare a resist composition. Here, the solid content means all components other than the solvent. The resulting resist compositions were used in Examples and Comparative Examples.

[Pattern formation and evaluation]
[Pattern formation and evaluation by EUV exposure: Examples 1 to 25, Comparative Example 1]
<Pattern formation>
An underlayer film forming composition SHB-A940 (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied onto a silicon wafer and baked at 205° C. for 60 seconds to form an underlayer film having a thickness of 20 nm. A resist composition shown in Table 15 was applied thereon and baked at 100° C. for 60 seconds to form a resist film having a thickness of 30 nm. Thus, a silicon wafer having a resist film was formed.
A silicon wafer having a resist film obtained by the above procedure was exposed using an EUV exposure apparatus (Exitech, Micro Exposure Tool, NA 0.3, Quadrupol, outer sigma 0.68, inner sigma 0.36). Pattern irradiation was performed. As the reticle, a mask having a line size of 20 nm and a line:space ratio of 1:1 was used.
The exposed resist film was baked at 90° C. for 60 seconds, developed with butyl acetate for 30 seconds, rinsed with butyl acetate, and spin-dried to obtain a pattern.

[Resolution evaluation (limit resolution, nm)]
In the above <pattern formation>, the exposure is performed at the optimum exposure dose Eop (μC/cm ² ) (the exposure dose when the pattern formed using the resist composition reproduces the pattern of the mask used for exposure). ing.
Next, a test was conducted in which a line-and-space pattern was formed by gradually changing the exposure amount from the optimum exposure amount Eop. At this time, the minimum dimension of the pattern that can be resolved without collapsing was determined using a scanning electron microscope (SEM (Hitachi Ltd. S-9380II)). This was defined as "limiting resolution (nm)". The smaller the limit resolution value, the better the resolution.
The resolution evaluation is preferably 16.3 nm or less, more preferably 15.0 nm or less, still more preferably 14.2 nm or less, particularly preferably 12.2 nm or less, and most preferably 11.0 nm or less.

[Performance evaluation: LWR (nm)]
The pattern obtained in <pattern formation> was observed from above using a 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 by 3σ to obtain LWR (nm). The smaller the value of LWR, the better the LWR performance.
The LWR evaluation is preferably 5.2 nm or less, more preferably 4.0 nm or less, particularly preferably 3.4 nm or less, and most preferably 2.9 nm or less.

Table 15 is shown below.

From the results in Table 15, it is clear that the resist compositions of Examples are excellent in resolution and also in LWR of the formed pattern.
Further, from a comparison of the examples, the repeating unit A of the specific polymer contained in the resist composition is a repeating unit represented by formula (1) (provided that the electron-withdrawing group is 8.5 or less) and When any one or more of the repeating units represented by formula (2) are present, and the resist composition satisfies any two or more (preferably four or more) of the following conditions A1 to A4, resolution It was confirmed that the properties are better and/or the LWR of the pattern formed is better.
(A1) The resist composition contains a photodegradable onium salt compound.
(A2) The specific polymer in the resist composition contains a repeating unit represented by formula (2)-1.
(A3) The specific polymer in the resist composition contains a repeating unit represented by formula (3)-1 (preferably formula (3)-1-1).
(A4) The weight-average molecular weight of the specific polymer in the resist composition is 30,000 or more.

Claims (17)

1. a polymer comprising a specific repeating unit selected from the group consisting of repeating units represented by formula (1) and repeating units represented by formula (2);
   An actinic ray-sensitive or radiation-sensitive resin composition containing a solvent.
   
   In Formula (1), X represents a halogen atom. R ¹ to R ³ each independently represent a hydrogen atom or a substituent. However, at least one of R ¹ and R ² represents an electron-withdrawing group.
   In Formula (2), X represents a halogen atom. ^R4 represents a hydrogen atom or a substituent. L ¹ and L ² each independently represent -CO-, -SO- or -SO ₂ -. ^L3 represents a single bond or a divalent linking group.
2. 2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein said electron-withdrawing group represents a group represented by any one of formulas (a) to (c).
   
   In formulas (a) to (c), R 1 ^X represents a hydrogen atom or a substituent. * represents a bonding site with the nitrogen atom in the formula (1).
3. 3. Actinic ray-sensitive or sensitive according to claim 1 or 2, wherein the specific repeating unit contains any one or more repeating units selected from the group consisting of formula (1)-1 and formula (2)-1 A radioactive resin composition.
   
   In formula (1)-1, X represents a halogen atom. R ¹ represents a hydrogen atom or a substituent. W is an electron-withdrawing group and represents a group represented by either -CO-R ^X or -SO ₂ -R ^X. R ^X represents a hydrogen atom or a substituent.
   In formula (2)-1, X represents a halogen atom. ^R4 represents a hydrogen atom or a substituent.
4. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 3, wherein the specific repeating unit comprises a repeating unit represented by formula (2)-1.
5. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the total content of the specific repeating units is 40 to 60 mol% with respect to all repeating units in the polymer.
6. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the polymer further contains a repeating unit represented by formula (3).
   
   In formula (3), ^R5 represents a hydrogen atom or a hydrocarbon group which may have a substituent.
   Z has a group represented by -NR ^f R ^g or a substituent in which -CH ₂ - may be substituted with a group selected from the group consisting of -O- and -CO- represents a good hydrocarbon group.
   R ^f represents a hydrocarbon group optionally having a substituent. ^Rg represents a hydrogen atom or a hydrocarbon group which may have a substituent. The R ^f and the R ^g may combine with each other to form a ring. Further, the optionally substituted hydrocarbon group represented by R ^f and the optionally substituted hydrocarbon group represented by R ^g each independently have —CH ₂ — It may be substituted with a group selected from the group consisting of -O-, -CO-, -SO- and -SO ₂ -.
7. The repeating unit represented by the formula (3) comprises any one or more repeating units selected from the group consisting of formulas (3)-1 to (3)-4. Actinic ray or radiation sensitive resin composition.
   
   In formula (3)-1, R ^a represents a hydrocarbon group which may have a substituent. R ^b represents a substituent. m represents 0 or 1; n represents an integer of 0 to 5;
   In formula (3)-2, R ^c and R ^d each independently represent a hydrocarbon group which may have a substituent. In the optionally substituted hydrocarbon group represented by R ^d , —CH ₂ — may be substituted with —CO—.
   In formula (3)-3, R ^e represents a hydrocarbon group which may have a substituent. R ^f represents a hydrocarbon group optionally having a substituent. ^Rg represents a hydrogen atom or a hydrocarbon group which may have a substituent. The R ^f and the R ^g may combine with each other to form a ring. Further, the optionally substituted hydrocarbon group represented by R ^f and the optionally substituted hydrocarbon group represented by R ^g each independently have —CH ₂ — It may be substituted with a group selected from the group consisting of -O-, -CO-, -SO- and -SO ₂ -.
   In formula (3)-4, each R ^h independently represents a hydrocarbon group which may have a substituent. R ⁱ represents a hydrogen atom or a hydrocarbon group which may have a substituent.
8. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 7, wherein the repeating unit represented by formula (3) contains a repeating unit represented by formula (3)-1.
9. 8. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 7, wherein the repeating unit represented by formula (3) contains a repeating unit represented by formula (3)-1-1.
   
   In formula (3)-1-1, R ^a represents a hydrocarbon group which may have a substituent. R ^b represents a substituent. n represents an integer of 0 to 5;
10. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the polymer has a weight average molecular weight of 30,000 or more.
11. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, further comprising a photodegradable onium salt compound.
12. A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2.
13. A step of forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2;
    exposing the resist film;
    and developing the exposed resist film using a developer containing an organic solvent.
14. A method for manufacturing an electronic device, including the pattern forming method according to claim 13.
15. A polymer comprising a specific repeating unit selected from the group consisting of repeating units represented by formula (1) and repeating units represented by formula (2).
    
    In Formula (1), X represents a halogen atom. R ¹ to R ³ each independently represent a hydrogen atom or a substituent. However, at least one of R ¹ and R ² represents an electron-withdrawing group.
    In Formula (2), X represents a halogen atom. ^R4 represents a hydrogen atom or a substituent. L ¹ and L ² each independently represent -CO-, -SO- or -SO ₂ -. ^L3 represents a single bond or a divalent linking group.
16. 16. The polymer according to claim 15, wherein the electron-withdrawing group represents a group represented by any one of formulas (a) to (c).
    
    In formulas (a) to (c), R 1 ^X represents a hydrogen atom or a substituent. * represents a bonding site with the nitrogen atom in the formula (1).
17. The polymer according to claim 15 or 16, wherein the specific repeating unit comprises one or more repeating units selected from the group consisting of formula (1)-1 and formula (2)-1.
    
    In formula (1)-1, X represents a halogen atom. R ¹ represents a hydrogen atom or a substituent. W is an electron-withdrawing group and represents a group represented by either -CO-R ^X or -SO ₂ -R ^X. R ^X represents a hydrogen atom or a substituent.
    In formula (2)-1, X represents a halogen atom. ^R4 represents a hydrogen atom or a substituent.