CN110673438A

CN110673438A - Resist composition and resist pattern forming method

Info

Publication number: CN110673438A
Application number: CN201910573761.9A
Authority: CN
Inventors: 大野庆晃; 河野绅一
Original assignee: Tokyo Ohka Kogyo Co Ltd
Current assignee: Tokyo Ohka Kogyo Co Ltd
Priority date: 2018-07-03
Filing date: 2019-06-28
Publication date: 2020-01-10
Also published as: KR20200004251A; JP7253883B2; JP2020008624A

Abstract

The invention provides a resist composition, which has excellent lithographic characteristics and good coating properties, and can inhibit foaming from a resist pattern during high-temperature baking, particularly when a thick resist film is formed to form a resist pattern. The resist composition of the present invention comprises: a polymer compound having a structural unit represented by formula (a10-1) and a structural unit containing an acid-decomposable group; the acid generator represented by the formula (b1) has a solid content concentration in the resist composition of 30% by mass or more. In the formula (a10-1), R is a hydrogen atom, an alkyl group or a haloalkyl group，Ya^x1Is a single bond or a 2-valent linking group, Wa^x1Is an aromatic hydrocarbon radical, n_ax1Is an integer of 1 to 3, wherein R in the formula (b)²⁰¹¹、R²⁰²¹And R²⁰³¹Each independently represents an aryl group, 2 or more of which may be bonded to each other to form a ring together with the sulfur atom in the formula, X^‑Denotes a counter anion.

Description

Resist composition and resist pattern forming method

Technical Field

The invention relates to a resist composition and a resist pattern forming method.

Background

In the photolithography technique, for example, the following steps are performed: a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light and subjected to a development process, thereby forming a resist pattern having a predetermined shape on the resist film. A resist material in which an exposed portion of the resist film is changed to a property of dissolving in a developer is called a positive type, and a resist material in which an exposed portion of the resist film is changed to a property of not dissolving in a developer is called a negative type.

In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, the miniaturization of patterns has been rapidly advanced due to the progress of photolithography. As a method for miniaturization, generally, the exposure light source is shortened in wavelength (increased in energy). Specifically, although ultraviolet rays typified by g-rays and i-rays have been used conventionally, semiconductor devices are now mass-produced using KrF excimer laser light or ArF excimer laser light. Further, studies have been conducted on EUV (extreme ultraviolet), EB (electron beam), X-ray, and the like, which have a shorter wavelength (higher energy) than these excimer lasers.

The resist material is required to have lithographic characteristics such as sensitivity to these exposure light sources and resolution with which a pattern of a fine size can be reproduced.

As a resist material satisfying such a demand, a chemically amplified resist composition containing a base component whose solubility in a developer changes by the action of an acid and an acid generator component which generates an acid upon exposure has been conventionally used.

For example, when the developer is an alkaline developer (alkaline developing process), a composition containing a resin component (base resin) whose solubility in the alkaline developer is increased by the action of an acid and an acid generator component is generally used as a positive chemically amplified resist composition. When a resist film formed using the resist composition is selectively exposed to light during formation of a resist pattern, an acid is generated from an acid generator component in an exposed portion, the polarity of a matrix resin is increased by the action of the acid, and the exposed portion of the resist film becomes soluble to an alkaline developer. Therefore, by performing the alkali development, a positive pattern in which an unexposed portion of the resist film remains as a pattern is formed.

On the other hand, when such a chemically amplified resist composition is applied to a solvent development process using a developer containing an organic solvent (organic developer), the solubility in the organic developer is relatively lowered when the polarity of the base resin is increased, and thus the unexposed portions of the resist film are dissolved and removed by the organic developer to form a negative resist pattern in which the exposed portions of the resist film remain as a pattern. The solvent development process for forming the negative resist pattern in this way is also sometimes referred to as a negative development process.

Heretofore, as a base resin of a chemically amplified resist composition, for example, Polyhydroxystyrene (PHS) having high transparency to KrF excimer laser light (248nm), a resin (PHS-based resin) in which a hydroxyl group thereof is protected by an acid-dissociable dissolution-inhibiting group, or a resin ((meth) acrylic resin) in which a hydroxyl group in a carboxyl group of (meth) acrylic acid is protected by an acid-dissociable dissolution-inhibiting group has been used (for example, see patent document 1).

As the acid dissociable dissolution inhibiting group, a so-called acetal group such as a chain ether group represented by 1-ethoxyethyl group or a cyclic ether group represented by tetrahydropyranyl group, a tertiary alkyl group represented by a tertiary butyl group, a tertiary alkoxycarbonyl group represented by a tertiary butoxycarbonyl group, or the like is mainly used.

Further, as an acid generator component used in a chemically amplified resist composition, various acid generator components have been proposed so far, and for example, an onium salt type acid generator such as an iodonium salt or a sulfonium salt, an oxime sulfonate type acid generator, a diazomethane type acid generator, a nitrobenzyl sulfonate type acid generator, an imino sulfonate type acid generator, a disulfone type acid generator, and the like are known.

In recent years, the photoelectric processing has become a mainstream of the precision microfabrication technology. The photolithography processing is a processing technique for producing various precision parts by applying the chemically amplified resist composition to the surface of a workpiece to form a resist film, forming a resist pattern having a predetermined shape on the resist film, and performing chemical etching, electrolytic etching, electroforming mainly using electroplating, or the like using the resist pattern as a mask.

In the above-mentioned photoelectric processing, depending on the application, a thick resist film having a film thickness of, for example, 8 μm or more is formed on the surface of the object, and a resist pattern is formed and etched.

Documents of the prior art

Patent document

Patent document 1 Japanese patent application laid-open No. 4-211258

Disclosure of Invention

Technical problem to be solved by the invention

When a thick resist film is formed using a chemically amplified resist composition, it is more difficult to apply the chemically amplified resist composition to a workpiece in a uniform thickness as the resist film becomes thicker. In addition, the formed resist pattern has a problem that lithographic characteristics (e.g., dimensional uniformity) are likely to be deteriorated.

In addition, when a resist pattern is formed using a chemically amplified resist composition, the thicker the resist film, the more difficult it is to maintain the sensitivity at the time of exposure. In contrast, for example, by using a chemically amplified resist composition in which an iodonium salt is selected as an acid generator component, sensitivity can be improved.

However, in the studies of the present inventors, it was confirmed that, when a chemically amplified resist composition containing an iodonium salt is used, foaming occurs when the support on which the resist film is formed is baked at a high temperature (180 ℃ or higher) (for example, when baking treatment (post-baking) is performed after development treatment or after rinsing treatment). In the resist composition which is likely to cause foaming in this manner, there is a problem that the effect of removing the residue is insufficient in ashing treatment for rework, for example.

The present invention has been made in view of the above circumstances, and has a technical problem in that: provided are a resist composition which has excellent lithographic characteristics and good coatability and which can suppress foaming from a resist pattern during high-temperature baking in the formation of a resist pattern, particularly in the formation of a resist pattern by forming a thick resist film, and a method for forming a resist pattern using the same.

Solution for solving the above technical problem

In order to solve the above-described problems, the present invention adopts the following configuration.

That is, the invention according to claim 1 is a resist composition which generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid, comprising: a polymer compound (A1) having a structural unit (a10) represented by the following general formula (a10-1) and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid; and an acid generator (B1) represented by the following general formula (B1), wherein the concentration of the solid component in the resist composition is 30% by mass or more.

[ CHEM 1]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms. Ya^x1Is a single bond or a 2-valent linking group. Wa^x1Is (n)_ax1+1) a valent aromatic hydrocarbon radical. n is_ax1Is an integer of 1 to 3, R²⁰¹¹、R²⁰²¹And R²⁰³¹Each independently represents an aryl group which may have a substituent. R²⁰¹¹、R²⁰²¹And R²⁰³¹2 or more of them may be bonded to each other to form a ring together with the sulfur atom in the formula. X^-Denotes a counter anion.]

The invention according to claim 2 is a resist pattern forming method including: a step (i) of forming a resist film on a support using the resist composition according to claim 1; a step (ii) of exposing the resist film; and (iii) developing the exposed resist film to form a resist pattern.

Effects of the invention

According to the present invention, it is possible to provide a resist composition which is excellent in lithographic characteristics and coatability and can suppress foaming from a resist pattern at the time of high-temperature baking in the formation of a resist pattern, particularly in the case of forming a resist pattern by forming a thick resist film, and a method for forming a resist pattern using the same.

The resist composition and the resist pattern forming method of the present invention are particularly suitable for forming a resist pattern of a thick film.

Detailed Description

In the present specification and the claims, "aliphatic" is a relative concept with respect to aromatic, and is defined to mean groups, compounds, and the like that do not have aromatic properties.

Unless otherwise specified, "alkyl" includes straight-chain, branched-chain and cyclic 1-valent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.

Unless otherwise specified, "alkylene" includes linear, branched and cyclic 2-valent saturated hydrocarbon groups.

The "haloalkyl group" is a group in which a part or all of hydrogen atoms of an alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

"fluoroalkyl" or "fluoroalkylene" refers to a group in which a part or all of the hydrogen atoms of an alkyl group or alkylene group are replaced with fluorine atoms.

The "structural unit" refers to a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).

When "may have a substituent" is described, the case where a hydrogen atom (-H) is substituted with a group having a valence of 1 and the case where a methylene group (-CH) is substituted are included₂-) two cases substituted with a 2-valent group.

"exposure" refers to a concept including irradiation of all radiation.

The "(meth) acrylate" refers to one or both of an acrylate having a hydrogen atom bonded to the α -position and a methacrylate having a methyl group bonded to the α -position.

The term "(meth) acrylic acid" refers to one or both of acrylic acid having a hydrogen atom bonded to the α -position and methacrylic acid having a methyl group bonded to the α -position.

The "structural unit derived from an acrylate" refers to a structural unit formed by cleavage of an ethylenic double bond of an acrylate.

"acrylate" is acrylic acid (CH)₂CH — COOH) in which a hydrogen atom at the carboxyl terminal is substituted with an organic group.

The hydrogen atom bonded to the carbon atom in the α -position of the acrylate may be substituted with a substituent. A substituent (R) for substituting the hydrogen atom bonded to the carbon atom at the alpha position^α0) Examples of the atom or group other than hydrogen atom include alkyl groups having 1 to 5 carbon atoms and halogenated alkyl groups having 1 to 5 carbon atoms. In addition, the compound also comprises a substituent (R)^α0) Itaconate diester substituted with a substituent comprising an ester bond, substituent (R)^α0) An alpha hydroxy acrylate substituted with a hydroxyalkyl group or a group modifying the hydroxyl group thereof. Unless otherwise specified, the carbon atom at the α -position of the acrylate refers to a carbon atom to which a carbonyl group of acrylic acid is bonded.

Hereinafter, an acrylate in which a hydrogen atom bonded to an α -position carbon atom is substituted with a substituent may be referred to as an α -substituted acrylate. Further, the acrylate and the α -substituted acrylate are also collectively referred to as "(α -substituted) acrylate".

The "structural unit derived from acrylamide" refers to a structural unit formed by cleavage of an ethylenic double bond of acrylamide.

The acrylamide may be obtained by substituting a substituent for a hydrogen atom bonded to a carbon atom in the α -position, or by substituting a substituent for one or both of hydrogen atoms of an amino group of the acrylamide. Unless otherwise specified, the carbon atom at the α -position of acrylamide refers to a carbon atom to which the carbonyl group of acrylamide is bonded.

Examples of the substituent for substituting the hydrogen atom bonded to the carbon atom at the α -position of acrylamide include the groups (substituents (R) listed as the α -position substituents in the above-mentioned α -substituted acrylic acid ester^α0) ) the same radicalAnd (4) clustering.

The "structural unit derived from hydroxystyrene" means a structural unit in which an olefinic double bond of hydroxystyrene is cleaved. The "structural unit derived from a hydroxystyrene derivative" means a structural unit in which an olefinic double bond of the hydroxystyrene derivative is cleaved.

The term "hydroxystyrene derivative" is intended to include compounds in which the hydrogen atom at the α -position of hydroxystyrene is substituted with another substituent such as an alkyl group or a haloalkyl group, and derivatives thereof. Examples of the derivatives include compounds in which the hydrogen atom at the α -position is substituted with a substituent, and the hydrogen atom of the hydroxyl group of hydroxystyrene is substituted with an organic group; and a compound in which a substituent other than a hydroxyl group is bonded to a benzene ring of hydroxystyrene in which a hydrogen atom at the α -position may be substituted with a substituent. In addition, the α -position (carbon atom at α -position) of hydroxystyrene means a carbon atom to which a benzene ring is bonded unless otherwise specified.

Examples of the substituent for substituting the hydrogen atom at the α -position of hydroxystyrene include the same groups as those listed as the substituent at the α -position in the above α -substituted acrylate.

The "structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative" refers to a structural unit in which an ethylenic double bond of vinylbenzoic acid or a vinylbenzoic acid derivative is cleaved.

The term "vinylbenzoic acid derivative" is intended to include compounds in which the hydrogen atom at the α -position of vinylbenzoic acid is substituted with other substituent such as alkyl group, haloalkyl group and the like, and their derivatives. Examples of the derivatives include compounds in which the hydrogen atom at the α -position is substituted with a substituent and the hydrogen atom of the carboxyl group of vinylbenzoic acid is substituted with an organic group; and a compound in which a hydrogen atom at the α -position is optionally substituted with a substituent, and a substituent other than a hydroxyl group and a carboxyl group is bonded to the benzene ring of vinylbenzoic acid. In addition, the α -position (carbon atom at α -position) of vinylbenzoic acid means a carbon atom to which a benzene ring is bonded unless otherwise specified.

"styrene" includes styrene and compounds in which the hydrogen atom alpha to styrene is substituted with other substituents such as alkyl and haloalkyl.

The term "styrene derivative" is intended to include compounds in which the hydrogen atom at the α -position of styrene is substituted with other substituents such as alkyl groups and haloalkyl groups, and derivatives thereof. Examples of the derivatives include compounds in which a substituent is bonded to a benzene ring of hydroxystyrene in which a hydrogen atom at the α -position may be substituted with a substituent. In addition, the α -position (carbon atom at α -position) means a carbon atom to which a benzene ring is bonded unless otherwise specified.

The "structural unit derived from styrene" and the "structural unit derived from a styrene derivative" mean a structural unit in which an ethylenic double bond of styrene or a styrene derivative is cleaved.

The alkyl group as the substituent at the α -position is preferably a linear or branched alkyl group, and specifically, an alkyl group having 1 to 5 carbon atoms (methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl) and the like are mentioned.

The haloalkyl group as the substituent at the α -position may specifically be a group obtained by substituting a part or all of hydrogen atoms of the above-mentioned "alkyl group as the substituent at the α -position" with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and a fluorine atom is particularly preferable.

Specific examples of the hydroxyalkyl group as the substituent at the α -position include those obtained by substituting a part or all of the hydrogen atoms of the above-mentioned "alkyl group as a substituent at the α -position" with a hydroxyl group. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, most preferably 1.

In the present description and in the claims, depending on the structure shown in the formula, asymmetric carbons exist and the structure of enantiomers (enantiomers) or diastereomers (diastereomers) may exist. In this case, these isomers are representatively shown in a chemical formula. These isomers may be used alone or as a mixture.

(resist composition)

The invention of claim 1 is the exposure to generate acid and the developer solubility due to acid changes of resist composition.

As an embodiment of the resist composition, there is exemplified a resist composition containing a base component (a) (hereinafter also referred to as "component a"), an acid generator component (B) (hereinafter also referred to as "component B"), and an organic solvent component (S) (hereinafter also referred to as "component S"), wherein the solubility of the base component (a) in a developer changes due to the action of an acid, and the acid generator component (B) generates an acid upon exposure. In the resist composition of the present embodiment, the component (a) contains a specific polymer compound (a1), the component (B) contains a specific acid generator (B1), and the solid content concentration in the resist composition is 30% by mass or more.

The resist composition of the present embodiment is suitable for resist pattern formation by exposure using a KrF excimer laser beam.

The resist composition of the present embodiment is suitable for forming a resist film of, for example, 1 to 10 μm on a support, and is particularly suitable for forming a resist pattern for forming a thick resist film. The thick film referred to herein is a film having a thickness of 6 μm or more. The resist composition of the present embodiment preferably has a thickness of 6 μm or more, and a resist film having a thickness of 7 μm or more, and further 8 μm or more is preferably formed in this range.

When a resist film is formed using the resist composition of the present embodiment and the resist film is selectively exposed, acid is generated from the component (B) in the exposed portion of the resist film, and the solubility of the component (a) in the developer changes due to the action of the acid, while the solubility of the component (a) in the developer does not change in the unexposed portion of the resist film, so that a difference in solubility in the developer occurs between the exposed portion and the unexposed portion of the resist film. Therefore, when the resist film is developed, in the case where the resist composition is a positive type, exposed portions of the resist film are dissolved and removed to form a positive type resist pattern, and in the case where the resist composition is a negative type, unexposed portions of the resist film are dissolved and removed to form a negative type resist pattern.

In this specification, a resist composition in which exposed portions of a resist film are dissolved and removed to form a positive resist pattern is referred to as a positive resist composition, and a resist composition in which unexposed portions of a resist film are dissolved and removed to form a negative resist pattern is referred to as a negative resist composition.

The resist composition of the present embodiment may be a positive resist composition or a negative resist composition.

The resist composition of the present embodiment is applicable to an alkaline development process using an alkaline developer in a development process in forming a resist pattern, and also applicable to a solvent development process using a developer containing an organic solvent (organic developer) in the development process.

The resist composition of the present embodiment has an acid generating ability to generate an acid upon exposure, and the component (a) may generate an acid upon exposure in addition to the component (B).

When the component (a) generates an acid by exposure, the component (a) is a "base component which generates an acid by exposure and whose solubility in a developer is changed by the action of an acid". (A) When the component (a) is a base component which generates an acid upon exposure and changes its solubility in a developer by the action of the acid, it is preferable that the component (a1) described later is a polymer compound which generates an acid upon exposure and changes its solubility in a developer by the action of the acid. Examples of such a polymer compound include resins having a structural unit that generates an acid upon exposure to light. As the monomer for deriving the structural unit which generates an acid by exposure, a known monomer can be used.

< ingredient (A) >

(A) The component is a base component whose solubility in the developer changes by the action of an acid.

In the present invention, the "base material component" is an organic compound having a film-forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, film formation ability is improved, and a resist pattern of a nanometer order is easily formed.

Organic compounds used as a component of the substrate are broadly classified into non-polymers and polymers.

As the non-polymer, a non-polymer having a molecular weight of 500 or more and less than 4000 is generally used. Hereinafter, in the case where "low molecular compound" is mentioned, it means a non-polymer having a molecular weight of 500 or more and less than 4000.

As the polymer, a polymer having a molecular weight of 1000 or more is generally used. Hereinafter, when "resin", "high molecular compound" or "polymer" is referred to, it means a polymer having a molecular weight of 1000 or more.

As the molecular weight of the polymer, a weight average molecular weight in terms of polystyrene based on GPC (gel permeation chromatography) was used.

As the component (a) used in the resist composition of the present embodiment, at least the component (a1) is used, and other high molecular compounds and/or low molecular compounds may be used in combination with the component (a 1).

In the resist composition of the present embodiment, the component (a) is a specific polymer compound (a1), namely, a polymer compound (a1) having a structural unit (a10) represented by the general formula (a10-1) described later and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid (hereinafter also referred to as a "component (a 1)").

When a resist film formed using a resist composition containing the component (a1) is exposed to light, the bonding of at least a part of the structure of the structural unit (a1) is cleaved by the action of an acid, and the polarity is increased. Therefore, the resist composition of the present embodiment is a negative type in the case where the developer is an organic developer (solvent development process), and is a positive type in the case where the developer is an alkaline developer (alkaline development process). Since the polarity of the (a1) component changes before and after exposure, a good development contrast can be obtained not only in the alkali development process but also in the solvent development process by using the (a1) component.

That is, when the alkaline developing process is applied, the component (a1) is hardly soluble in an alkaline developer before exposure, and when an acid is generated from the component (B) by exposure, the polarity of the acid increases by the action of the acid, and the solubility in the alkaline developer increases. Therefore, in the formation of a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed, the solubility of the exposed portion of the resist film in an alkaline developer is changed from poorly soluble to soluble, while the unexposed portion of the resist film remains poorly soluble and does not change, and thus a positive resist pattern is formed by alkaline development.

On the other hand, in the case of applying the solvent development process, the solubility of the component (a1) in the organic developer before exposure is high, and when acid is generated from the component (B) by exposure, the polarity thereof becomes high by the action of the acid, and the solubility in the organic developer is reduced. Therefore, in the formation of a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed, the solubility of the exposed portion of the resist film in an organic developer changes from soluble to poorly soluble, while the unexposed portion of the resist film remains soluble and does not change, so that by developing with an organic developer, a contrast can be obtained between the exposed portion and the unexposed portion, and a negative resist pattern can be formed.

With respect to the (A1) component

(A1) Component (b) is a polymer compound having a structural unit (a10) represented by the general formula (a10-1) and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid.

Structural unit (a10)

The structural unit (a10) is a structural unit represented by the following general formula (a 10-1).

[ CHEM 2]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms. Ya^X1Is a single bond or a 2-valent linking group. Wa^X1Is (n)_ax1Aryl of +1) valencyAn aromatic hydrocarbon group. n is_ax1Is an integer of 1 to 3.]

In the formula (a10-1), R is hydrogen atom, alkyl group with 1-5 carbon atoms or halogenated alkyl group with 1-5 carbon atoms.

The alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, it is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, or the like. The haloalkyl group having 1 to 5 carbon atoms as R is a group in which a part or all of hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and a fluorine atom is particularly preferable.

R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluoroalkyl group having 1 to 5 carbon atoms, and a hydrogen atom or a methyl group is most preferable from the viewpoint of easy industrial availability.

In said formula (a10-1), Ya^x1Is a single bond or a 2-valent linking group.

As Ya^x1The 2-valent linking group in (2) includes, for example, a 2-valent hydrocarbon group which may have a substituent, and a 2-valent linking group containing a hetero atom as a preferable group.

A 2-valent hydrocarbon group which may have a substituent

At Ya^x1When the hydrocarbon group is a 2-valent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

··Ya^x1Aliphatic hydrocarbon group of (1)

The aliphatic hydrocarbon group means a hydrocarbon group having no aromatic character. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and is preferably a saturated aliphatic hydrocarbon group.

Examples of the aliphatic hydrocarbon group include a straight-chain or branched-chain aliphatic hydrocarbon group, an aliphatic hydrocarbon group having a ring in the structure, and the like.

Linear or branched aliphatic hydrocarbon radical

The number of carbon atoms of the straight-chain aliphatic hydrocarbon group is preferably 1 to 10, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3.

The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specifically, a methylene group [ -CH ] may be mentioned₂-]Ethylene [ - (CH)₂)₂-]Propylene [ - (CH)₂)₃-]Butylene [ - (CH)₂)₄-]- (CH) pentylene [ - (CH)₂)₅-]And the like.

The branched aliphatic hydrocarbon group preferably has 3 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, still more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms.

The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include-CH (CH)₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-and the like alkylmethylene; -CH (CH)₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-、-C(CH₂CH₃)₂-CH₂-and the like, an alkyl ethylene group; -CH (CH)₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-and the like, alkyl propylene; -CH (CH)₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂An alkylalkylene group such as an alkylbutylene group. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluoroalkyl group having 5 or more carbon atoms and being substituted with a fluorine atom, and a carbonyl group.

Aliphatic hydrocarbon groups containing rings in the structure

Examples of the aliphatic hydrocarbon group having a ring in the structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing 2 hydrogen atoms from an aliphatic hydrocarbon ring) having a hetero atom in the ring structure and optionally having a substituent, a group obtained by bonding the cyclic aliphatic hydrocarbon group to an end of a linear or branched aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed between linear or branched aliphatic hydrocarbon groups. Examples of the linear or branched aliphatic hydrocarbon group include the same aliphatic hydrocarbon groups as described above.

The number of carbon atoms of the cyclic aliphatic hydrocarbon group is preferably 3 to 20, more preferably 3 to 12.

The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing 2 hydrogen atoms from a monocycloparaffin. The monocycloalkane is preferably a monocycloalkane having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing 2 hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably a C7-12 polycycloalkane, and specifically includes adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.

The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, and a carbonyl group.

The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a tert-butoxy group, and most preferably a methoxy group or an ethoxy group.

Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

Examples of the haloalkyl group as the substituent include groups in which a part or all of hydrogen atoms of the alkyl group are substituted with the halogen atom.

Of cyclic aliphatic hydrocarbon groups constituting the ring structure thereofA part of the carbon atoms of (a) may also be substituted with a heteroatom-containing substituent. The heteroatom-containing substituent is preferably-O-, -C (═ O) -O-, -S-, -S (═ O)₂-、-S(＝O)₂-O-。

··Ya^x1Aromatic hydrocarbon radical in (1)

The aromatic hydrocarbon group is a hydrocarbon group having at least 1 aromatic ring.

The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n +2 pi electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. Wherein the number of carbons does not include the number of carbons in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, phenanthrene, and the like; and an aromatic heterocyclic ring in which a part of carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocyclic ring include a pyridine ring and a thiophene ring.

Specific examples of the aromatic hydrocarbon group include a group (arylene group or heteroarylene group) obtained by removing 2 hydrogen atoms from the aromatic hydrocarbon ring or aromatic heterocyclic ring; a group obtained by removing 2 hydrogen atoms from an aromatic compound (for example, biphenyl, fluorene, or the like) having 2 or more aromatic rings; and a group (aryl or heteroaryl) obtained by removing 1 hydrogen atom from the aromatic hydrocarbon ring or the aromatic heterocyclic ring, wherein 1 hydrogen atom is substituted with an alkylene group (for example, a group obtained by removing 1 hydrogen atom from an aryl group in an arylalkyl group such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl, etc.), and the like. The number of carbon atoms of the alkylene group bonded to the aryl or heteroaryl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

In the aromatic hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, and a hydroxyl group.

The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

Examples of the alkoxy group, the halogen atom, and the haloalkyl group as the substituent include those exemplified as the substituent for substituting the hydrogen atom of the cyclic aliphatic hydrocarbon group.

Heteroatom-containing 2-valent linking groups:

at Ya^x1In the case of a 2-valent linking group containing a hetero atom, preferable examples of the linking group include-O-, -C (═ O) -, -O-C (═ O) -O-, -C (═ O) -NH-, -NH-C (═ NH) - (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, -S (═ O)₂-、-S(＝O)₂-O-, of the formula-Y²¹-O-Y²²-、-Y²¹-O-、-Y²¹-C(＝O)-O-、-C(＝O)-O-Y²¹-、-[Y²¹-C(＝O)-O]_m”-Y²²-、-Y²¹-O-C(＝O)-Y²²-or-Y²¹-S(＝O)₂-O-Y²²A group represented by (wherein Y is)²¹And Y²²Each independently a 2-valent hydrocarbon group which may have a substituent, O is an oxygen atom, and m' is an integer of 0 to 3]And the like.

In the case where the heteroatom-containing 2-valent linking group is — C (═ O) -NH-, -C (═ O) -NH-C (═ O) -, -NH-C (═ NH) -, H thereof may be substituted with a substituent such as an alkyl group or an acyl group. The number of carbon atoms of the substituent (such as alkyl group or acyl group) is preferably 1 to 10, more preferably 1 to 8, and particularly preferably 1 to 5.

General formula-Y²¹-O-Y²²-、-Y²¹-O-、-Y²¹-C(＝O)-O-、-C(＝O)-O-Y²¹-、-[Y²¹-C(＝O)-O]_m”-Y²²-、-Y²¹-O-C(＝O)-Y²²-or-Y²¹-S(＝O)₂-O-Y²²In (Y)²¹And Y²²Each independently is a 2-valent hydrocarbon group which may have a substituent. The 2-valent hydrocarbon group may be the one mentioned in the description of the 2-valent linking group (which may have a substituent)The 2-valent hydrocarbon group) of (a).

As Y²¹The aliphatic hydrocarbon group is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms, and particularly preferably a methylene group or an ethylene group.

As Y²²The aliphatic hydrocarbon group is preferably a linear or branched aliphatic hydrocarbon group, and more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

Is represented by the formula- [ Y ]²¹-C(＝O)-O]_m”-Y²²In the group represented by (A), m' is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, as represented by the formula- [ Y ]²¹-C(＝O)-O]_m”-Y²²A group represented by the formula-Y is particularly preferred²¹-C(＝O)-O-Y²²-a group represented by (a). Among them, the formula- (CH) is preferred₂)_a’-C(＝O)-O-(CH₂)_b’-a group represented by (a). In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, further preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, still more preferably 1 or 2, and most preferably 1.

As Ya^x1Preferably a single bond, an ester bond [ -C (═ O) -O-]An ether bond (-O-) -, -C (-O) -NH linear or branched alkylene group, or a combination thereof, and among them, a single bond is more preferable.

In the formula (a10-1), Wa^x1Is (n)_ax1+1) a valent aromatic hydrocarbon radical.

As Wa^x1The aromatic hydrocarbon group in (1) includes those removed from aromatic ring (n)_ax1+1) hydrogen atoms. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n +2 pi electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. As the aromatic ringSpecific examples thereof include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, phenanthrene, and the like; and an aromatic heterocyclic ring in which a part of carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocyclic ring include a pyridine ring and a thiophene ring.

In the formula (a10-1), n_ax1Is an integer of 1 to 3, preferably 1 or 2, more preferably 1.

Specific examples of the structural unit represented by the above formula (a10-1) are shown below.

In the formula, R^αRepresents a hydrogen atom, a methyl group or a trifluoromethyl group.

[ CHEM 3 ]

(A1) The constituent unit (a10) of component (a) may be 1 or 2 or more.

Among the above, the structural unit (a10) is preferably a structural unit having a hydroxystyrene skeleton, and particularly preferably a structural unit represented by the following general formula (a 10-1-1).

[ CHEM 4 ]

[ in the formula, R^stRepresents a hydrogen atom or a methyl group. m is₀₁Represents an integer of 1 to 3.]

(A1) The proportion of the structural unit (a10) in the component (a1) is preferably 10 to 95 mol%, more preferably 30 to 90 mol%, and particularly preferably 50 to 85 mol% based on the total (100 mol%) of all the structural units constituting the component (a 1).

By setting the ratio of the structural unit (a10) to be equal to or higher than the lower limit of the above-described preferable range, it is easy to further improve the developing property, the lithographic property such as the EL limit (Margin), and the like, and by setting the ratio of the structural unit (a10) to be equal to or lower than the upper limit of the above-described preferable range, it is easy to balance with other structural units.

Structural unit (a1)

The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity is increased by the action of an acid.

The "acid-decomposable group" is an acid-decomposable group having a structure in which at least a part of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid.

Examples of the acid-decomposable group whose polarity is increased by the action of an acid include groups which are decomposed by the action of an acid to generate a polar group.

Examples of the polar group include a carboxyl group, a hydroxyl group, an amino group, and a sulfonic acid group (-SO)₃H) And the like. Among these, a polar group containing-OH in the structure (hereinafter also referred to as "OH-containing polar group") is preferable, a carboxyl group or a hydroxyl group is more preferable, and a carboxyl group is particularly preferable.

More specifically, the acid-decomposable group includes a group in which the polar group is protected by an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected by an acid-dissociable group).

The "acid-dissociable group" herein means both of the following: (i) an acid-dissociable group having a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group that can be cleaved by the action of an acid; or (ii) a group in which a part of the bond is cleaved by the action of an acid and then decarboxylation is further caused, whereby the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved.

The acid-dissociable group constituting the acid-dissociable group must be a group having a polarity lower than that of a polar group generated by dissociation of the acid-dissociable group, and thus when the acid-dissociable group dissociates by the action of an acid, a polar group having a polarity higher than that of the acid-dissociable group is generated and the polarity increases. As a result, the polarity of the entire component (a1) increases. The solubility in the developer changes relatively due to the increase in polarity, and the solubility increases when the developer is an alkaline developer and decreases when the developer is an organic developer.

Examples of the acid-dissociable group include those proposed as acid-dissociable groups of matrix resins for chemically amplified resists.

Specific examples of the group proposed as the acid-dissociable group of the base resin for a chemically amplified resist include "acetal acid-dissociable group", "tert-alkyl ester acid-dissociable group", and "tert-alkoxycarbonyl acid-dissociable group" described below.

Acetal type acid-dissociable group:

examples of the acid-dissociable group that protects the carboxyl group or the hydroxyl group of the polar group include acid-dissociable groups represented by the following general formula (a1-r-1) (hereinafter also referred to as "acetal-type acid-dissociable groups").

[ CHEM 5 ]

[ wherein, Ra'¹、Ra’²Is a hydrogen atom or an alkyl group, Ra'³Is hydrocarbyl, Ra'³May be substituted with Ra'¹、Ra’²Any of which is bonded to form a ring.]

In the formula (a1-r-1), Ra 'is preferred'¹And Ra'²At least one of them is a hydrogen atom, and more preferably both are hydrogen atoms.

In Ra'¹Or Ra'²In the case of an alkyl group, the alkyl group may be the same as the alkyl group exemplified as the substituent which may be bonded to the carbon atom at the α -position in the above description of the α -substituted acrylate, and is preferably an alkyl group having 1 to 5 carbon atoms. Specifically, a linear or branched alkyl group can be preferably mentioned. More specifically, there may be mentioned methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl and the like, more preferably methyl or ethyl,methyl is particularly preferred.

In the formula (a1-r-1), as Ra'³Examples of the hydrocarbon group of (3) include a linear or branched alkyl group and a cyclic hydrocarbon group.

The number of carbon atoms of the linear alkyl group is preferably 1 to 5, more preferably 1 to 4, and further preferably 1 or 2. Specific examples thereof include methyl group, ethyl group, n-propyl group, n-butyl group, and n-pentyl group. Among these, methyl, ethyl or n-butyl is preferable, and methyl or ethyl is more preferable.

The branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms. Specific examples thereof include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group, 1-diethylpropyl group, and 2, 2-dimethylbutyl group, with isopropyl group being preferred.

In Ra'³When the hydrocarbon group is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, or may be a polycyclic group or a monocyclic group.

The alicyclic hydrocarbon group as a monocyclic group is preferably a group obtained by removing 1 hydrogen atom from a monocyclic hydrocarbon. The monocyclic hydrocarbon is preferably a monocyclic hydrocarbon having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane.

The aliphatic hydrocarbon group of the polycyclic group is preferably a group obtained by removing 1 hydrogen atom from a polycycloalkane, and the polycycloalkane is preferably a C7-12 polycycloalkane, and specifically includes adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.

When the cyclic hydrocarbon group of Ra' 3 is an aromatic hydrocarbon group, the aromatic hydrocarbon group has at least 1 aromatic ring.

The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n +2 pi electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, phenanthrene, and the like; and an aromatic heterocyclic ring in which a part of carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocyclic ring include a pyridine ring and a thiophene ring.

As Ra'³Specific examples of the aromatic hydrocarbon group in (1) include a group (aryl group or heteroaryl group) obtained by removing 1 hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocyclic ring; a group obtained by removing 1 hydrogen atom from an aromatic compound (for example, biphenyl, fluorene, or the like) having 2 or more aromatic rings; and those in which 1 hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocyclic ring is substituted with an alkylene group (for example, arylalkyl groups such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl and 2-naphthylethyl). The number of carbon atoms of the alkylene group bonded to the aromatic hydrocarbon ring or the aromatic heterocyclic ring is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

Ra’³And Ra'¹、Ra’²In the case where any one of these groups is bonded to form a ring, the cyclic group is preferably a four-to seven-membered ring, and more preferably a four-to six-membered ring. Specific examples of the cyclic group include tetrahydropyranyl group and tetrahydrofuranyl group.

Tertiary alkyl ester type acid-dissociable group:

examples of the acid-dissociable group that protects the carboxyl group of the polar group include acid-dissociable groups represented by the following general formula (a 1-r-2).

For convenience of explanation, a group composed of an alkyl group in the acid-dissociable group represented by the following general formula (a1-r-2) will be referred to as a "tertiary alkyl ester-type acid-dissociable group" hereinafter.

[ CHEM 6 ]

[ wherein, Ra'⁴～Ra’⁶Are each hydrocarbyl, Ra'⁵、Ra’⁶May be bonded to each other to form a ring.]

As Ra'⁴～Ra’⁶The hydrocarbon group of (2) may be represented by the above Ra'³The same hydrocarbon group.

Ra’⁴Preferably an alkyl group having 1 to 5 carbon atoms. In Ra'⁵And Ra'⁶When they are bonded to each other to form a ring, a group represented by the following general formula (a1-r2-1) may be mentioned. On the other hand, in Ra'⁴～Ra’⁶When the hydrocarbon groups are independent of each other, preferred examples thereof include groups represented by the following general formula (a1-r 2-2).

[ CHEM 7 ]

[ wherein, Ra'¹⁰Represents an alkyl group having 1 to 10 carbon atoms. Ra'¹¹Is represented by and Ra'¹⁰The bonded carbon atoms together form the radical of an alicyclic group. Ra'¹²～Ra’¹⁴Each independently represents a hydrocarbon group.]

Ra 'of the formula (a1-r 2-1)'¹⁰The alkyl group having 1 to 10 carbon atoms in (a1-r-1) is preferably Ra'³Examples of the linear or branched alkyl group of (1) are listed below. Ra 'of the formula (a1-r 2-1)'¹¹And Ra'¹⁰The alicyclic ring group formed together with the bonded carbon atoms is preferably Ra 'in the formula (a 1-r-1)'³The alicyclic hydrocarbon group of (1) monocyclic group or polycyclic group is exemplified.

In the formula (a1-r2-2), Ra'¹²And Ra'¹⁴Each independently is preferably an alkyl group having 1 to 10 carbon atoms, and the alkyl group is more preferably Ra 'in the formula (a 1-r-1)'³The group exemplified as the linear or branched alkyl group of (2) is more preferably a linear alkyl group having 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group.

In the formula (a1-r2-2), Ra'¹³Preferably Ra 'in the formula (a 1-r-1)'³Examples of the hydrocarbon group of (3) include a linear or branched alkyl group and an aliphatic hydrocarbon group which is a monocyclic group or polycyclic group. Of these, Ra'¹³More preferably as Ra'³Examples of the hydrocarbon group of (1) include linear or branched alkyl groups.

Specific examples of the group represented by the above formula (a1-r2-1) are listed below. Indicates a bond (the same as in the present specification hereinafter).

[ CHEM 8 ]

[ CHEM 9 ]

Specific examples of the group represented by the above formula (a1-r2-2) are listed below.

[ CHEM 10 ]

Tertiary alkoxycarbonyl acid-dissociable group:

examples of the acid-dissociable group that protects the hydroxyl group of the polar group include an acid-dissociable group represented by the following general formula (a1-r-3) (hereinafter, also referred to as a "tertiary alkoxycarbonyl acid-dissociable group" for convenience of description).

[ CHEM 11 ]

[ wherein, Ra'⁷～Ra’⁹Are each an alkyl group.]

In the formula (a1-r-3), Ra'⁷～Ra’⁹Each preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms.

The total number of carbon atoms of each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

Among the above, the acid-dissociable group as the base resin for a chemically amplified resist is preferably a tertiary alkyl ester type acid-dissociable group, more preferably an acid-dissociable group represented by the formula (a1-r-2), and still more preferably a group represented by the general formula (a1-r2-2), from the viewpoint of easily obtaining the effect of combining with the component (B) (resolution, dimensional uniformity (CDU) in the surface of the support (Shot), etc.).

Among the groups represented by the general formula (a1-r2-2), preferred are groups represented by the above formula (r-pr-c1), formula (r-pr-c2) or formula (r-pr-c 3).

Examples of the structural unit (a1) include a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α -position is substituted with a substituent, a structural unit derived from acrylamide, a structural unit in which at least a part of hydrogen atoms in hydroxyl groups of a structural unit derived from hydroxystyrene or a hydroxystyrene derivative is protected with a substituent containing the acid-decomposable group, a structural unit in which at least a part of hydrogen atoms in-C (═ O) -OH of a structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative is protected with a substituent containing the acid-decomposable group, and the like.

Among the above, as the structural unit (a1), a structural unit derived from an acrylate in which a hydrogen atom bonded to a carbon atom at the α -position may be substituted with a substituent is preferable.

Preferable specific examples of the structural unit (a1) include structural units represented by the following general formula (a1-1) or (a 1-2).

[ CHEM 12 ]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms. Va (Va)¹Is a 2-valent hydrocarbon group which may have an ether bond, n_a1Is an integer of 0 to 2, Ra¹Is an acid-dissociable group represented by the above formula (a1-r-1) or (a 1-r-2). Wa¹Is n_a2A hydrocarbon radical having a valence of +1, n_a2Is 1 to 3, Ra²Is an acid-dissociable group represented by the formula (a1-r-1) or (a 1-r-3).]

In the above formula (a1-1), the alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, it includes methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl and the like. The C1-5 haloalkyl is a group in which a part or all of the hydrogen atoms of the C1-5 alkyl are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and a fluorine atom is particularly preferable.

R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluoroalkyl group having 1 to 5 carbon atoms, and most preferably a hydrogen atom or a methyl group, from the viewpoint of easy industrial availability.

In the formula (a1-1), Va¹With a 2-valent hydrocarbon group which may have an ether bond and Ya in the formula (a10-1)^x1The same applies to the 2-valent hydrocarbon group which may have an ether bond as a substituent.

In the formula (a1-2), Wa¹N in (1)_a2The +1 valent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromatic character, and may be a saturated group or an unsaturated group, and is usually preferably a saturated group. Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group having a ring in the structure, or a combination of a linear or branched aliphatic hydrocarbon group and an aliphatic hydrocarbon group having a ring in the structure.

N is_a2The +1 valence is preferably 2 to 4 valence, more preferably 2 or 3 valence.

Specific examples of the structural unit represented by the above formula (a1-1) are shown below.

In the following formulae, R^αRepresents a hydrogen atom, a methyl group or a trifluoromethyl group.

[ CHEM 13 ]

[ CHEM 14 ]

[ CHEM 15 ]

[ CHEM 16 ]

[ CHEM 17 ]

Specific examples of the structural unit represented by the above formula (a1-2) are shown below.

[ CHEM 18 ]

(A1) The constituent unit (a1) of component (a) may be 1 or 2 or more.

(A1) The proportion of the structural unit (a1) in component (a) is preferably 5 to 90 mol%, more preferably 10 to 70 mol%, particularly preferably 15 to 50 mol%, based on the total (100 mol%) of all the structural units constituting component (a 1).

By setting the ratio of the structural unit (a1) to be equal to or higher than the lower limit of the preferable range, the contrast between the exposed portion and the unexposed portion of the resist film can be further improved, and the resolution can be improved. On the other hand, by setting the upper limit value of the preferable range to be equal to or less than the upper limit value, balance with other constituent units can be obtained.

Other structural units

(A1) Component (c) may have other structural units in addition to the structural unit (a10) and the structural unit (a 1).

Examples of the other structural unit include a lactone ring-containing group and an-SO-containing group₂-a cyclic group or a carbonate-containing cyclic group-containing structural unit (a2) (wherein structural units belonging to structural unit (a10) or structural unit (a1) are excluded); a structural unit (a4) containing an acid-non-dissociable alicyclic group; a structural unit derived from styrene, a structural unit derived from a styrene derivative (wherein the structural unit belonging to the structural unit (a10) is excluded); a structural unit of an aliphatic hydrocarbon group having a polar group (wherein a structural unit belonging to any of the structural units is not included), and the like.

Structural unit (a2)

The structural unit (a2) is a lactone ring-containing group-SO-containing group₂A cyclic group or a structural unit containing a carbonate cyclic group (excluding a structural unit belonging to the structural unit (a10) or the structural unit (a 1)).

The lactone ring-containing group of the structural unit (a2) contains-SO₂When the component (a1) is used for forming a resist film, a cyclic group or a cyclic group containing carbonate is effective in improving adhesion of the resist film to a substrate. Further, by making the (a1) component have the structural unit (a2), the solubility of the resist film in an alkaline developer during development can be improved in the alkaline development process.

The "lactone ring-containing group" refers to a cyclic group containing a ring (lactone ring) containing — O — C (═ O) -, in the ring skeleton thereof. The lactone ring is referred to as the first ring, and when the lactone ring is present alone, the lactone ring is referred to as a monocyclic group, and when the lactone ring has another ring structure, the lactone ring is referred to as a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.

The lactone ring-containing group in the structural unit (a2) is not particularly limited, and any lactone ring-containing group can be used. Specifically, there may be mentioned groups represented by the following general formulae (a2-r-1) to (a 2-r-7).

[ CHEM 19 ]

[ wherein, Ra'²¹Each independently is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, -COOR ", -OC (═ O) R", a hydroxyalkyl group or a cyano group; r' is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a-SO-containing group₂-a cyclic group. A' is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (-O-) or a sulfur atom (-S-), an oxygen atom or a sulfur atom. n 'is an integer of 0 to 2, and m' is 0 or 1.]

In the general formulae (a2-r-1) to (a2-r-7) as Ra'²¹The alkyl group in (1) is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples thereof include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, and hexyl. Among these, methyl or ethyl is preferable, and methyl is particularly preferable.

As Ra'²¹The alkoxy group in (1) is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the Ra 'may be mentioned'²¹The alkyl group in (1) is a group in which an alkyl group is bonded to an oxygen atom (-O-).

As Ra'²¹Examples of the halogen atom in (b) include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

As Ra'²¹Examples of the haloalkyl group in (1) include the above Ra'²¹Wherein a part or all of hydrogen atoms of the alkyl group in (1) are substituted by the halogen atom. The haloalkyl group is preferably a fluoroalkyl group, and particularly preferably a perfluoroalkyl group.

Ra’²¹In the group-COOR ", -OC (. ═ O) R", R "is each a hydrogen atom, an alkyl group, a lactone ring-containing group, a carbonate ring-containing group, or a group containing-SO₂-a cyclic group.

The alkyl group in R' may be linear, branched or cyclic, and the number of carbon atoms is preferably 1 to 15.

When R' is a linear or branched alkyl group, the number of carbon atoms is preferably 1 to 10, more preferably 1 to 5, and particularly preferably a methyl group or an ethyl group.

When R' is a cyclic alkyl group, the number of carbon atoms is preferably 3 to 15, more preferably 4 to 12, and most preferably 5 to 10. Specifically, there can be exemplified a group obtained by removing 1 or more hydrogen atoms from a monocycloparaffin which may be substituted or unsubstituted with a fluorine atom or a fluoroalkyl group; and groups obtained by removing 1 or more hydrogen atoms from a multicycloparaffin such as bicycloalkane, tricycloalkane or tetracycloalkane. More specifically, there may be mentioned a group obtained by removing 1 or more hydrogen atoms from a monocycloparaffin such as cyclopentane or cyclohexane; and groups obtained by removing 1 or more hydrogen atoms from a polycyclic alkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like.

Examples of the lactone ring-containing group in R' include the same groups as those represented by the above general formulae (a2-R-1) to (a 2-R-7).

As the carbonate-containing cyclic group in R', there may be mentioned, in the same manner as the carbonate-containing cyclic group described later, specifically, groups represented by general formulae (ax3-R-1) to (ax3-R-3), respectively.

As containing-SO in R₂A cyclic group with-SO-containing as described later₂As the cyclic group, there may be mentioned those represented by the general formulae (a5-r-1) to (a 5-r-4).

As Ra'²¹The hydroxyalkyl group in (1) is preferably a hydroxyalkyl group having 1 to 6 carbon atoms, and concretely, the above Ra'²¹Wherein at least 1 of the hydrogen atoms of the alkyl group in (1) is substituted with a hydroxyl group.

In the general formulae (a2-r-2), (a2-r-3) and (a2-r-5), the alkylene group having 1 to 5 carbon atoms in A' is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group and an isopropylene group. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group having-O-or-S-interposed between the terminal or carbon atom of the alkylene group, and examples thereof include-O-CH₂-、-CH₂-O-CH₂-、-S-CH₂-、-CH₂-S-CH₂-and the like. A' is preferably an alkylene group having 1 to 5 carbon atoms or-O-, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

Specific examples of the groups represented by the general formulae (a2-r-1) to (a2-r-7) are shown below.

[ CHEM 20 ]

[ CHEM 21 ]

"contains-SO₂The term "cyclic group" means a group containing-SO in its ring skeleton₂The cyclic group of the ring of (A) is, in particular, -SO₂The sulfur atom (S) in (E) forms a cyclic group which is part of the ring skeleton of the cyclic group. The ring skeleton of the catalyst contains-SO₂The ring of (E) is referred to as a first ring, and is referred to as a monocyclic group when only the ring is present, and is referred to as a polycyclic group when the ring has other ring structures. containing-SO₂The cyclic group may be a monocyclic group or a polycyclic group.

containing-SO₂The cyclic group is particularly preferably one having-O-SO in the ring skeleton₂A cyclic radical, i.e. containing-O-SO₂-O-S-in (a) -forms the cyclic group of the sultone ring forming part of the ring backbone.

As containing-SO₂More specifically, examples of the cyclic group include groups represented by the following general formulae (a5-r-1) to (a 5-r-4).

[ CHEM 22 ]

[ wherein, Ra'⁵¹Each independently is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, -COOR ", -OC (═ O) R", a hydroxyalkyl group or a cyano group. R' is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a-SO-containing group₂-a cyclic group. A' is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom. n' is an integer of 0 to 2.]

In the general formulae (a5-r-1) to (a5-r-2), A 'is the same as A' in the general formulae (a2-r-2), (a2-r-3) and (a 2-r-5).

As Ra'⁵¹Examples of the alkyl group, alkoxy group, halogen atom, haloalkyl group, -COOR ', -OC (═ O) R ', hydroxyalkyl group in (a2-R-1) to (a2-R-7) include Ra '²¹The same groups as those listed in the description of (1).

Specific examples of the groups represented by the general formulae (a5-r-1) to (a5-r-4) are shown below. "Ac" in the formula represents an acetyl group.

[ CHEM 23 ]

[ CHEM 24 ]

[ CHEM 25 ]

The "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) having a ring skeleton containing — O — C (═ O) -O-. The carbonate ring is referred to as the first ring, and when only the carbonate ring is present, the carbonate ring is referred to as a monocyclic group, and when the carbonate ring has another ring structure, the carbonate ring is referred to as a polycyclic group regardless of the structure. The cyclic group containing carbonate may be a monocyclic group or a polycyclic group.

The cyclic group containing a carbonic ester is not particularly limited, and any cyclic group containing a carbonic ester can be used. Specifically, there can be mentioned groups represented by the following general formulae (ax3-r-1) to (ax 3-r-3).

[ CHEM 26 ]

[ wherein, Ra'^x31Each independently is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, -COOR ", -OC (═ O) R", a hydroxyalkyl group or a cyano group. R' is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a-SO-containing group₂-a cyclic group. A' is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom. p 'is an integer of 0 to 3, and q' is 0 or 1.]

In the general formulae (ax3-r-2) to (ax3-r-3), A 'is the same as A' in the general formulae (a2-r-2), (a2-r-3) and (a 2-r-5).

As Ra'³¹Examples of the alkyl group, alkoxy group, halogen atom, haloalkyl group, -COOR ', -OC (═ O) R ', hydroxyalkyl group in (a2-R-1) to (a2-R-7) include Ra '²¹The same groups as those listed in the description of (1).

Specific examples of the groups represented by the general formulae (ax3-r-1) to (ax3-r-3) are shown below.

[ CHEM 27 ]

As the structural unit (a2), among them, a structural unit derived from an acrylate in which a hydrogen atom bonded to a carbon atom at the α -position may be substituted with a substituent is preferable.

The structural unit (a2) is preferably a structural unit represented by the following general formula (a 2-1).

[ CHEM 28 ]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms. Ya²¹Is a single bond or a 2-valent linking group. La²¹is-O-, -COO-, -CON (R ') -, -OCO-, -CONHCO-or-CONHCS-, and R' represents a hydrogen atom or a methyl group. Wherein, in La²¹In the case of-O-, Ya²¹Will not be-CO-. Ra²¹Is a lactone ring group-containing, carbonate ring group-containing or-SO-containing group₂-a cyclic group.]

In the formula (a2-1), R is the same as described above.

As Ya²¹As the 2-valent linking group in (a), there can be mentioned the group corresponding to Ya in the above-mentioned general formula (a10-1)^x1The 2-valent linking group in (1) is the same linking group. Wherein, as Ya²¹Preferably a single bond, an ester bond [ -C (═ O) -O-]An ether bond (-O-), a linear or branched alkylene group, or a combination thereof.

In the formula (a2-1), Ra²¹Is a lactone ring group-containing, SO-containing₂-a cyclic group or a carbonate-containing cyclic group.

As Ra²¹In (1), the lactone ring-type group-containing compound contains-SO₂The cyclic group and the carbonate-containing cyclic group may preferably be represented by the general formulae (a2-r-1) to (a2-r-7), the general formulae (a5-r-1) to (a5-r-4), and the general formulae (ax3-r-1) to (ax 3-r-3).

Wherein, Ra²¹Preferably containing a lactone ring group or containing-SO₂A cyclic group, more preferably a group represented by the general formula (a2-r-1), (a2-r-2), (a2-r-6) or (a5-r-1), respectively. More specifically, any of the above-mentioned chemical formulae (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc-6-1), (r-sl-1-1), and (r-sl-1-18) is more preferable.

(A1) The constituent unit (a2) of component (a) may be 1 or 2 or more.

When the component (a1) has the structural unit (a2), the proportion of the structural unit (a2) in the component (a1) is preferably 1 to 40 mol%, more preferably 2 to 20 mol%, and still more preferably 5 to 10 mol% based on the total (100 mol%) of all the structural units constituting the component (a 1).

When the proportion of the structural unit (a2) is not less than the lower limit of the above preferable range, the effect of containing the structural unit (a2) can be sufficiently obtained. On the other hand, if the upper limit of the above-described preferable range is not more than the upper limit, balance with other constituent units can be obtained, and various lithographic characteristics and pattern shapes can be improved.

Structural unit (a4)

The structural unit (a4) is a structural unit containing an acid-non-dissociable alicyclic group.

When the component (a1) has the structural unit (a4), the resist pattern formed has improved dry etching resistance. The hydrophobicity of the component (A) is improved. In particular, in the case of forming a resist pattern by a solvent development process, the improvement of hydrophobicity contributes to the improvement of resolution, resist pattern shape, and the like.

The "acid-non-dissociable cyclic group" in the structural unit (a4) is a cyclic group that does not dissociate even by the action of an acid when the acid is generated in the resist composition by exposure (for example, when the acid is generated from the component (B) described later), and remains as it is in the structural unit.

As the structural unit (a4), for example, a structural unit derived from an acrylate containing an acid-non-dissociable alicyclic group is preferable. As the alicyclic group, a large number of groups known to be used as resin components of resist compositions for ArF excimer lasers, KrF excimer lasers (preferably for ArF excimer lasers), and the like can be used.

Particularly, at least 1 kind selected from the group consisting of tricyclodecyl group, adamantyl group, tetracyclododecyl group, isobornyl group and norbornyl group is preferable from the viewpoint of easy industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

As the structural unit (a4), specific examples thereof include structural units represented by the following general formulae (a4-1) to (a 4-7).

[ CHEM 29 ]

[ in the formula, R^αAs before.]

(A1) The constituent unit (a4) of component (a) may be 1 or 2 or more.

When the component (a1) has the structural unit (a4), the proportion of the structural unit (a4) in the component (a1) is preferably 1 to 30 mol%, more preferably 3 to 20 mol%, based on the total (100 mol%) of all the structural units constituting the component (a 1).

By setting the proportion of the structural unit (a4) to be equal to or higher than the lower limit of the above-mentioned preferable range, the effect of containing the structural unit (a4) can be sufficiently obtained. On the other hand, when the content is not more than the upper limit of the preferable range, balance with other constituent units can be easily obtained.

Structural units derived from styrene

When the component (a1) has a structural unit derived from styrene, the proportion of the structural unit derived from styrene in the component (a1) is preferably 1 to 30 mol%, more preferably 3 to 20 mol%, based on the total (100 mol%) of all the structural units constituting the component (a 1).

In the resist composition of the embodiment, the component (a) includes a polymer compound (a1) having a structural unit (a10) and a structural unit (a 1).

The component (a1) is preferably a polymer compound having a repeating structure of the structural unit (a10) and the structural unit (a1), and particularly preferably a polymer compound having a repeating structure of the structural unit (a10), the structural unit (a1) and a structural unit derived from styrene.

(A1) The weight average molecular weight (Mw) of the component (D) is preferably 5000 to 20000, more preferably 7000 to 15000, and still more preferably 8000 to 13000, in terms of polystyrene based on Gel Permeation Chromatography (GPC).

When the Mw of the component (a1) is not more than the upper limit of the above preferable range, the viscosity of the resist composition is easily suppressed from becoming too high, and the coatability of the resist composition onto the support is further improved. In addition, the resist composition can easily have sufficient solubility in a resist solvent when used as a resist, and sensitivity can be easily improved. On the other hand, if the lower limit value of the above preferable range is not less than the above preferable range, a thick resist film can be easily formed. Further, the dry etching resistance and the cross-sectional shape of the resist pattern become more favorable.

(A1) The molecular weight distribution (Mw/Mn) of the component (B) is not particularly limited, but is preferably about 1.0 to 4.0, more preferably 1.0 to 3.0, and particularly preferably 1.5 to 2.5. In addition, Mn represents a number average molecular weight.

The component (a1) contained in the resist composition may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

(A) The proportion of the component (a1) in the component (a) is preferably 25% by mass or more, more preferably 50% by mass or more, further preferably 75% by mass or more, and may be 100% by mass, based on the total mass of the component (a). When the ratio of the component (a1) is equal to or higher than the lower limit of the above-described preferable range, a resist pattern having high sensitivity, high resolution, dimensional uniformity in the support surface (Shot), and excellent other lithographic characteristics can be easily formed.

In the resist composition according to the embodiment, the concentration of the polymer compound (a1) is preferably 15 to 50 mass%, more preferably 25 to 45 mass%, and still more preferably 30 to 40 mass%, based on the total weight (100 mass%) of the resist composition.

If the concentration of the component (a1) in the resist composition is equal to or higher than the lower limit of the above-mentioned preferable range, a thick resist film is easily formed, while if the concentration is equal to or lower than the upper limit of the above-mentioned preferable range, the viscosity of the resist composition is easily suppressed from becoming too high.

In the resist composition of the present embodiment, 1 kind of the component (a) may be used alone, or 2 or more kinds may be used in combination.

The content of the component (a) in the resist composition of the present embodiment may be adjusted according to the thickness of a resist film to be formed.

< ingredient (B) >

The resist composition of the present embodiment contains an acid generator component (B) (hereinafter referred to as "component (B)") in addition to the component (a).

The component (B) includes a specific acid generator (B1), i.e., an acid generator (B1) represented by the general formula (B1) described later (hereinafter referred to as "component (B1)"). By containing the (B1) component, foaming during high-temperature baking can be suppressed in resist pattern formation. In addition, when a resist pattern is formed, it becomes easy to maintain good sensitivity, and the lithographic characteristics (such as dimensional uniformity) are improved.

Related (B1) component

(B1) The component (b) is an acid generator represented by the following general formula (b 1).

[ CHEM 30 ]

[ in the formula, R²⁰¹¹、R²⁰²¹And R²⁰³¹Each independently represents an aryl group which may have a substituent. R²⁰¹¹、R²⁰²¹And R²⁰³¹2 or more of them may be bonded to each other to form a ring together with the sulfur atom in the formula. X^-Denotes a counter anion.]

In the formula (b1), R²⁰¹¹、R²⁰²¹And R²⁰³¹Each independently represents an aryl group which may have a substituent.

As R²⁰¹¹、R²⁰²¹And R²⁰³¹Examples of the aryl group in (1) include unsubstituted aryl groups having 6 to 20 carbon atoms, and preferably phenyl and naphthyl groups.

As R²⁰¹¹、R²⁰²¹And R²⁰³¹Examples of the substituent which may be contained in the aryl group in (1) include an alkyl group, a halogen atom, a haloalkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulae (ca-r-1) to (ca-r-7).

The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and is preferably a straight-chain or branched alkyl group.

The haloalkyl group as the substituent is preferably a haloalkyl group having 1 to 5 carbon atoms, a straight-chain or branched-chain haloalkyl group.

Examples of the aryl group as a substituent include aryl groups having 6 to 20 carbon atoms, and preferably phenyl groups and naphthyl groups.

[ CHEM 31 ]

[ wherein R'²⁰¹Each independently represents a hydrogen atom, a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent.]

In the formulae (ca-R-1) to (ca-R-7), R'²⁰¹Each independently represents a hydrogen atom, a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent.

A cyclic group which may have a substituent:

the cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromatic character. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and is preferably a saturated aliphatic hydrocarbon group.

R’²⁰¹The aromatic hydrocarbon group in (1) is a hydrocarbon group having an aromatic ring. The number of carbon atoms of the aromatic hydrocarbon group is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. Wherein the carbon number does not include the carbon number in the substituent.

As R'²⁰¹Specific examples of the aromatic ring of the aromatic hydrocarbon group in (3) include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and an aromatic heterocycle in which a part of carbon atoms constituting the aromatic ring is substituted with a hetero atom. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom.

As R'²⁰¹Specific examples of the aromatic hydrocarbon group in (1) include a group obtained by removing 1 hydrogen atom from the aromatic ring (an aryl group: e.g., phenyl, naphthyl, etc.), a group in which 1 hydrogen atom of the aromatic ring is substituted with an alkylene group (e.g., an arylalkyl group such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl, etc.), and the like. The number of carbon atoms of the alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

R’²⁰¹The cyclic aliphatic hydrocarbon group in (2) includes an aliphatic hydrocarbon group having a ring in the structure.

Examples of the aliphatic hydrocarbon group having a ring in the structure include an alicyclic hydrocarbon group (a group obtained by removing 1 hydrogen atom from an aliphatic hydrocarbon ring), a group obtained by bonding an alicyclic hydrocarbon group to the end of a linear or branched aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed between linear or branched aliphatic hydrocarbon groups.

The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.

The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing 1 or more hydrogen atoms from a monocyclic hydrocarbon. The monocycloparaffins are preferably monocycloparaffins having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing 1 or more hydrogen atoms from a polycyclic hydrocarbon, and the polycyclic alkane is preferably a polycyclic alkane having 7 to 30 carbon atoms. The polycyclic alkane includes a polycyclic alkane having a polycyclic skeleton, such as a crosslinked ring-type polycyclic alkane, e.g., adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane; more preferably, the polycyclic alkane has a polycyclic skeleton of a condensed ring system, such as a cyclic group having a steroid skeleton.

Wherein, R'²⁰¹The cyclic aliphatic hydrocarbon group in (1) is preferably a group obtained by removing 1 or more hydrogen atoms from a monocycloparaffin or polycycloalkane, more preferably a group obtained by removing 1 hydrogen atom from a polycycloalkane, particularly preferably an adamantyl group or a norbornyl group, and most preferably an adamantyl groupAn alkyl group.

The number of carbon atoms of the straight or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group is preferably 1 to 10, more preferably 1 to 6, still more preferably 1 to 4, and particularly preferably 1 to 3.

The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specifically includes methylene [ -CH ]₂-]Ethylene [ - (CH)₂)₂-]Propylene [ - (CH)₂)₃-]Butylene [ - (CH)₂)₄-]- (CH) pentylene [ - (CH)₂)₅-]And the like.

The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specifically includes-CH (CH)₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-isoalkylmethylene; -CH (CH)₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-、-C(CH₂CH₃)₂-CH₂-isoalkylethylene; -CH (CH)₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-isoalkylpropylene; -CH (CH)₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂An alkylalkylene group such as an alkylbutylene group, etc. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

Furthermore, R'²⁰¹The cyclic hydrocarbon group in (2) may contain a hetero atom like a heterocycle and the like. Specifically, there may be mentioned lactone ring-containing groups represented by the general formulae (a2-r-1) to (a2-r-7) and-SO-containing groups represented by the general formulae (a5-r-1) to (a5-r-4)₂A cyclic group and other heterocyclic groups represented by the following chemical formulae (r-hr-1) to (r-hr-16).

[ CHEM 32 ]

Further, examples of the cyclic group which may have a substituent include the same groups as the acid-dissociable group represented by the above formula (a 1-r-2).

As R'²⁰¹Examples of the substituent in the cyclic group in (b) include an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, a carbonyl group, and a nitro group.

The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a tert-butoxy group, and most preferably a methoxy group or an ethoxy group.

Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

Examples of the haloalkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, for example, groups in which some or all of hydrogen atoms of a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, and the like are substituted with the above-mentioned halogen atom.

The carbonyl group as the substituent is a methylene group (-CH) substituted for the cyclic hydrocarbon group₂-) of (a) a group of (b).

Chain alkyl group which may have a substituent:

as R'²⁰¹The chain alkyl group of (b) may be either linear or branched.

The straight chain alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specific examples thereof include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, isohexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, and docosyl.

The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples thereof include 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl and 4-methylpentyl.

Examples of the chain alkyl group which may have a substituent include the same groups as the acid-dissociable group represented by the above formula (a 1-r-2).

Chain alkenyl group which may have a substituent:

as R'²⁰¹The chain alkenyl group (b) may be either straight-chain or branched, and the number of carbon atoms is preferably 2 to 10, more preferably 2 to 5, still more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butenyl group. Examples of the branched alkenyl group include a 1-methylethenyl group, a 2-methylethenyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group.

Among the above, the linear alkenyl group is preferably a linear alkenyl group, more preferably a vinyl group or a propenyl group, and particularly preferably a vinyl group.

As R'²⁰¹Examples of the substituent in the chain alkyl group or the chain alkenyl group include an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and the above R'²⁰¹Cyclic group in (1), and the like.

Of the above, R'²⁰¹The cyclic group may have a substituent, and more preferably a cyclic hydrocarbon group may have a substituent. More specifically, for example, a group obtained by removing 1 or more hydrogen atoms from a phenyl group, a naphthyl group, or a polycycloalkane; lactone ring-containing groups represented by the general formulae (a2-r-1) to (a2-r-7), respectively; containing-SO represented by the general formulae (a5-r-1) to (a5-r-4) respectively₂-cyclic groups, etc. Among these, more preferred is a group which may have a substituent and is obtained by removing 1 or more hydrogen atoms from a cycloalkane.

Preferably, (B1) contained in the resist composition of the embodiment) In the general formula (b1), R²⁰¹¹、R²⁰²¹And R²⁰³¹At least 1 of them is an aryl group having a substituent. By reacting R²⁰¹¹、R²⁰²¹And R²⁰³¹At least 1 of them is an aryl group having a substituent, and therefore, foaming at the time of high-temperature baking is easily suppressed, and the solubility to an organic solvent is improved, and precipitation at the time of development or the like becomes difficult to occur. In addition, the process margin in pattern formation tends to be large, and the depth of field (DOF) characteristics, for example, tend to be improved.

In this case, R is²⁰¹¹、R²⁰²¹And R²⁰³¹The substituent having an aryl group in (1) is preferably at least 1 selected from the group consisting of an alkyl group, a halogen atom, a haloalkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the above general formulae (ca-r-1) to (ca-r-7).

The R is²⁰¹¹、R²⁰²¹And R²⁰³¹2 or more of them may be bonded to each other to form a ring together with the sulfur atom in the formula.

When a ring is formed in this manner, a heteroatom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or a carbonyl group, -SO-, -SO₂-、-SO₃-, -COO-, -CONH-or-N (R)_N) - (the R)_NAlkyl group having 1 to 5 carbon atoms) and the like.

The ring to be formed is preferably a three-to ten-membered ring in which 1 ring including the sulfur atom in the formula in the ring skeleton includes a sulfur atom, and particularly preferably a five-to seven-membered ring. Specific examples of the ring to be formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

Specific examples of the preferable cation in the acid generator represented by the general formula (b1) include cations represented by the following chemical formulas (ca-1-1) to (ca-1-55).

[ CHEM 33 ]

[ CHEM 34 ]

[ CHEM 35 ]

[ wherein g1, g2 and g3 represent the number of repetitions, g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20. ]

[ CHEM 36 ]

In the formula (b1), X^-Denotes a counter anion.

As the X^-The acid generator component used in the resist composition may be any one of a known acid generator component, an acid generator component, and a known acid generator component.

For example, as X^-Examples thereof include anions represented by the following general formula (b1-a1), anions represented by the following general formula (b1-a2), and anions represented by the following general formula (b1-a 3).

[ CHEMICAL ] 37

[ in the formula, R¹⁰¹、R¹⁰⁴～R¹⁰⁸Each independently represents a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent. R¹⁰⁴、R¹⁰⁵May be bonded to each other to form a ring. R¹⁰²Is a fluorine atom orA fluoroalkyl group having 1 to 5 carbon atoms. Y is¹⁰¹Is a 2-valent linking group containing a single bond or an oxygen atom. V¹⁰¹～V¹⁰³Each independently a single bond, alkylene, or fluoroalkylene. L is¹⁰¹～L¹⁰²Each independently a single bond or an oxygen atom. L is¹⁰³～L¹⁰⁵Each independently of the other being a single bond, -CO-or-SO₂-。]

An anion represented by the general formula (b1-a1)

In the formula (b1-a1), R¹⁰¹Examples of the substituent(s) include a cyclic group which may have a substituent(s), a chain alkyl group which may have a substituent(s), and a chain alkenyl group which may have a substituent(s), and the groups are respectively mentioned with R in the above-mentioned formulae (ca-R-1) to (ca-R-7)^’201The same groups.

In the above, R¹⁰¹The cyclic group may have a substituent, and more preferably a cyclic hydrocarbon group may have a substituent. More specifically, the following is preferable: groups obtained by removing 1 or more hydrogen atoms from phenyl, naphthyl and polycycloalkane; lactone ring-containing groups represented by the general formulae (a2-r-1) to (a 2-r-7); containing-SO represented by the general formulae (a5-r-1) to (a5-r-4) respectively₂-cyclic groups, etc.

In the formula (b1-a1), Y¹⁰¹Is a 2-valent linking group containing a single bond or an oxygen atom.

At Y¹⁰¹In the case of a 2-valent linking group containing an oxygen atom, Y¹⁰¹Atoms other than oxygen atoms may also be contained. Examples of the atom other than the oxygen atom include a carbon atom, a hydrogen atom, a sulfur atom, and a nitrogen atom.

Examples of the oxygen atom-containing 2-valent linking group include non-hydrocarbon oxygen atom-containing linking groups such as an oxygen atom (ether bond: -O-), an ester bond (-C (═ O) -O-), an oxycarbonyl (-O-C (═ O) -), an amide bond (-C (═ O) -NH-), a carbonyl (-C (═ O) -), a carbonate bond (-O-C (═ O) -O-; combinations of the non-hydrocarbon oxygen atom-containing linking groups and alkylene groups, and the like. In this combination, a sulfonyl group (-SO) may be further bonded₂-). Examples of the above-mentioned oxygen atom-containing 2-valent linking group include linking groups represented by the following general formulae (y-al-1) to (y-al-7)And (4) clustering.

[ CHEM 38 ]

[ in the formula, V'¹⁰¹Is a single bond or C1-5 alkylene group, V'¹⁰²Is a C1-30 saturated hydrocarbon group with a valence of 2.]

V’¹⁰²The 2-valent saturated hydrocarbon group in (1) is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and still more preferably an alkylene group having 1 to 5 carbon atoms.

As V'¹⁰¹And V'¹⁰²The alkylene group in (b) may be a linear alkylene group or a branched alkylene group, and is preferably a linear alkylene group.

As V'¹⁰¹And V'¹⁰²The alkylene group in (1) includes, specifically, methylene [ -CH ]₂-]；-CH(CH₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-isoalkylmethylene; ethylene [ -CH₂CH₂-]；-CH(CH₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-isoalkylethylene; propylene (n-propylene) [ -CH₂CH₂CH₂-]；-CH(CH₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-isoalkylpropylene; butylene [ -CH₂CH₂CH₂CH₂-]；-CH(CH₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂-isoalkylbutylene; pentylene [ -CH₂CH₂CH₂CH₂CH₂-]And the like.

Furthermore, V'¹⁰¹Or V'¹⁰²Wherein a part of methylene groups in the alkylene group in (1) may be substituted with a 2-valent alicyclic group having 5 to 10 carbon atoms. The alicyclic group is preferably derived from Ra in the formula (a1-r-1)^’3The cyclic aliphatic hydrocarbon group (monocyclic alicyclic hydrocarbon group, polycyclic alicyclic hydrocarbon group) of (2) is a 2-valent group obtained by further removing 1 hydrogen atom, and more preferably a cyclohexylene group, a1, 5-adamantylene group or a2, 6-adamantylene group.

As Y¹⁰¹The linking group having a valence of 2 comprising an ester bond or the linking group having a valence of 2 comprising an ether bond is preferable, and the linking groups represented by the above formulae (y-al-1) to (y-al-5) are more preferable.

In the formula (b1-a1), V¹⁰¹Is a single bond, alkylene or fluoroalkylene. V¹⁰¹The alkylene group and fluoroalkylene group in (1) are preferably C1-C4. As V¹⁰¹In (3), the fluoroalkylene group includes V¹⁰¹Wherein a part or all of hydrogen atoms of the alkylene group in (1) are substituted by fluorine atoms. Wherein, V¹⁰¹Preferably a single bond or a C1-4 fluoroalkylene group.

In the formula (b1-a1), R¹⁰²Is a fluorine atom or a fluoroalkyl group having 1 to 5 carbon atoms. R¹⁰²Preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, more preferably a fluorine atom.

As a specific example of the anion portion represented by the above formula (b1-a1), for example, Y¹⁰¹In the case of a single bond, a fluoroalkylsulfonate anion such as trifluoromethanesulfonate anion or perfluorobutanesulfonate anion may be mentioned. At Y¹⁰¹In the case of a 2-valent linking group containing an oxygen atom, an anion represented by any one of the following general formulae (an-1) to (an-3) can be mentioned.

[ CHEM 39 ]

[ in the formula, R "¹⁰¹Is an alicyclic group which may have a substituent, groups represented by the formulae (r-hr-1) to (r-hr-6) or a chain alkyl group which may have a substituent. R'¹⁰²Can have substitutionAn alicyclic cyclic group, lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7), or-SO-containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4)₂-a cyclic group. R'¹⁰³The group is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent. V'¹⁰¹Is a single bond, an alkylene group having 1 to 4 carbon atoms or a fluoroalkylene group having 1 to 4 carbon atoms. R¹⁰²Is a fluorine atom or a fluoroalkyl group having 1 to 5 carbon atoms. V ' is an independent integer of 0-3, q ' is an independent integer of 1-20, and n ' is 0 or 1.]

R”¹⁰¹、R”¹⁰²And R "¹⁰³The alicyclic group which may have a substituent(s) is preferably as the R¹⁰¹The cyclic aliphatic hydrocarbon group in (1) is exemplified. As the substituent, there may be mentioned optionally substituted R¹⁰¹The cyclic aliphatic hydrocarbon group in (1) has the same substituent.

R”¹⁰³The aromatic cyclic group which may have a substituent(s) in (1) is preferably the R¹⁰¹Examples of the aromatic hydrocarbon group in the cyclic hydrocarbon group in (1) are given. As the substituent, there may be mentioned optionally substituted R¹⁰¹The aromatic hydrocarbon group in (1) has the same substituent.

R”¹⁰¹The chain alkyl group which may have a substituent(s) in (1) is preferably the R group¹⁰¹The chain alkyl group in (1) above. R'¹⁰³The optionally substituted chain alkenyl group in (1) is preferably the R group¹⁰¹The chain alkenyl group in (1) is exemplified as a group.

In the formulae (an-1) to (an-3), V "¹⁰¹Is a single bond, an alkylene group having 1 to 4 carbon atoms or a fluoroalkylene group having 1 to 4 carbon atoms. V'¹⁰¹Preferably a single bond, an alkylene group having 1 carbon atom (methylene group), or a fluoroalkylene group having 1 to 3 carbon atoms.

In the formulae (an-1) to (an-3), R¹⁰²Is a fluorine atom or a fluoroalkyl group having 1 to 5 carbon atoms. R¹⁰²Preferably a C1-5 perfluoroalkyl group or a fluorine atom, more preferably a fluorine atom.

In the formulae (an-1) to (an-3), v "is an integer of 0 to 3, and more preferably 0 or 1. q' is an integer of 1 to 20, preferably an integer of 1 to 10, more preferably an integer of 1 to 5, further preferably 1, 2 or 3, and particularly preferably 1 or 2. n "is 0 or 1.

An anion represented by the general formula (b1-a2)

In the formula (b1-a2), R¹⁰⁴、R¹⁰⁵Each of which is independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and R in the formula (b1-a1)¹⁰¹The same groups. Wherein R is¹⁰⁴、R¹⁰⁵May be bonded to each other to form a ring.

R¹⁰⁴、R¹⁰⁵The alkyl group is preferably a chain alkyl group which may have a substituent, more preferably a linear or branched alkyl group or a linear or branched fluoroalkyl group.

The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and still more preferably 1 to 3 carbon atoms. R is also good in solubility in a solvent for a resist, and the like¹⁰⁴、R¹⁰⁵The carbon number of the chain alkyl group (2) is preferably as small as possible within the above-mentioned range of carbon numbers. Furthermore, R¹⁰⁴、R¹⁰⁵The chain alkyl group (2) is preferred because the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength.

The proportion of fluorine atoms in the chain alkyl group, that is, the fluorination rate, is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms.

In the formula (b1-a2), V¹⁰²、V¹⁰³Each independently a single bond, an alkylene group or a fluoroalkylene group, and V in the formula (b1-a1)¹⁰¹The same groups.

In the formula (b1-a2), L¹⁰¹、L¹⁰²Each independently a single bond or an oxygen atom.

An anion represented by the general formula (b1-a3)

In the formula (b1-a3), R¹⁰⁶～R¹⁰⁸Each independently represents a cyclic group which may have a substituent(s), may have a substituent(s)Examples of the substituted chain alkyl group or the substituted chain alkenyl group include the same groups as those mentioned for R in the formula (b1-a1)¹⁰¹The same groups.

In the formula (b1-a3), L¹⁰³～L¹⁰⁵Each independently of the other being a single bond, -CO-or-SO₂-。

Among the above, the anion portion of the component (B1) is preferably an anion represented by the general formula (B1-a 1). When the component (B1) having the anion as the anion portion is used, the dimensional uniformity in the surface of the support can be further improved in the formation of the resist pattern. For example, when forming a pattern of spaces and lines, the variation in the size (CD) of the space width is small, and it becomes easy to form a pattern of a uniform width with high accuracy.

Among these anions, anions represented by any of the above general formulae (an-1) to (an-3) are more preferable, anions represented by any of the general formulae (an-1) and (an-2) are still more preferable, and anions represented by the general formula (an-1) are particularly preferable.

Specific examples of the preferable component (B1) are described below.

[ CHEM 40 ]

The component (B1) contained in the resist composition may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

(B) The proportion of the component (B1) in the component (a) is preferably 50% by mass or more, more preferably 75% by mass or more, and may be 100% by mass, based on the total mass of the component (B). When the proportion of the component (B1) is not less than the lower limit of the above preferable range, foaming during high-temperature baking can be further suppressed. In addition, when a resist pattern is formed, good sensitivity is easily maintained, and the lithographic characteristics (such as dimensional uniformity) are improved.

In the resist composition of the present embodiment, the content of the component (B1) is preferably 1 to 40 parts by mass, more preferably 1.5 to 35 parts by mass, and still more preferably 2 to 30 parts by mass, based on 100 parts by mass of the component (a).

When the content of the component (B1) is not less than the lower limit of the above preferable range, foaming during high-temperature baking can be further suppressed. In addition, when a resist pattern is formed, good sensitivity is easily maintained, and the lithographic characteristics (such as dimensional uniformity) are improved. On the other hand, if the upper limit of the above preferable range is not more than the upper limit, a uniform solution is easily obtained when the components of the resist composition are dissolved in the organic solvent, and the storage stability as a resist composition is further improved.

With respect to the (B2) component

The resist composition of the present embodiment may contain an acid generator component (hereinafter referred to as "component B2") other than the component (B1) within a range not to impair the effects of the present invention.

The component (B2) is not particularly limited, and acid generators proposed heretofore as acid generators for use in chemically amplified resist compositions can be used.

Examples of such an acid generator include onium salt type acid generators such as iodonium salts and sulfonium salts, oxime sulfonate type acid generators; diazomethane acid generators such as dialkyl or bisarylsulfonyl diazomethane and poly (bissulfo) diazomethane; a plurality of acid generators such as nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators and the like.

As the onium salt-type acid generator, for example, a compound represented by the following general formula (b-1) (hereinafter also referred to as "component (b-1)"), a compound represented by the following general formula (b-2) (hereinafter also referred to as "component (b-2)") or a compound represented by the following general formula (b-3) (hereinafter also referred to as "component (b-3)") can be used.

[ CHEM 41 ]

[ in the formula, R¹⁰¹、R¹⁰⁴～R¹⁰⁸Each independently represents a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent. R¹⁰⁴、R¹⁰⁵Can be mutually bondedAnd then combined to form a ring. R¹⁰²Is a fluorine atom or a fluoroalkyl group having 1 to 5 carbon atoms. Y is¹⁰¹Is a single bond or a 2-valent linking group comprising an oxygen atom. V¹⁰¹～V¹⁰³Each independently a single bond, alkylene, or fluoroalkylene. L is¹⁰¹～L¹⁰²Each independently a single bond or an oxygen atom. L is¹⁰³～L¹⁰⁵Each independently of the other being a single bond, -CO-or-SO₂-. M is an integer of 1 or more, M'^m+Is an onium cation having a valence of m.]

{ anion portion }

The anion portion of the component (b-1) is the same as the anion represented by the general formula (b1-a 1).

The anion portion of the component (b-2) is the same as the anion represented by the general formula (b1-a 2).

The anion portion of the component (b-3) is the same as the anion represented by the general formula (b1-a 3).

{ cation portion }

M 'in the formulae (b-1), (b-2) and (b-3)'^m+Represents an m-valent onium cation (excluding a cation belonging to the cation portion in the above general formula (b 1)). Among them, sulfonium cations and iodonium cations can be preferably cited.

As preferred cationic portion ((M'^m+)_1/m) Examples thereof include organic cations represented by the following general formulae (ca-1) to (ca-4).

[ CHEM 42 ]

[ in the formula, R²⁰¹～R²⁰⁷And R²¹¹～R²¹²Each independently represents an aryl group, an alkyl group or an alkenyl group which may have a substituent. R²⁰¹～R²⁰³、R²⁰⁶～R²⁰⁷、R²¹¹～R²¹²May be bonded to each other to form a ring together with the sulfur atom in the formula. R²⁰⁸～R²⁰⁹Each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R²¹⁰Is aryl which may have a substituent(s), may haveAlkyl group which may have substituent, alkenyl group which may have substituent, or-SO-containing group which may have substituent₂-a cyclic group. L is²⁰¹represents-C (═ O) -or-C (═ O) -O-. Y is²⁰¹Each independently represents an arylene group, an alkylene group or an alkenylene group. x is 1 or 2. W²⁰¹Represents a (x +1) -valent linking group.]

In the above general formulae (ca-1) to (ca-4), R is²⁰¹～R²⁰⁷And R²¹¹～R²¹²Examples of the aryl group in (1) include unsubstituted aryl groups having 6 to 20 carbon atoms, and preferably phenyl and naphthyl groups.

As R²⁰¹～R²⁰⁷And R²¹¹～R²¹²The alkyl group in (2) is a chain or cyclic alkyl group, preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.

As R²⁰¹～R²⁰⁷And R²¹¹～R²¹²The alkenyl group in (1) is preferably a C2-10 group.

As R²⁰¹～R²⁰⁷And R²¹⁰～R²¹²Examples of the substituent which may be present include an alkyl group, a halogen atom, a haloalkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the above general formulae (ca-r-1) to (ca-r-7).

In the above general formulae (ca-1) to (ca-4), R is²⁰¹～R²⁰³、R²⁰⁶～R²⁰⁷、R²¹¹～R²¹²When they are bonded to each other to form a ring together with the sulfur atom in the formula, they may be bonded to each other via a heteroatom such as a sulfur atom, an oxygen atom, a nitrogen atom or the like, a carbonyl group, -SO-, -SO₂-、-SO₃-, -COO-, -CONH-or-N (R)_N) - (the R)_NAlkyl group having 1 to 5 carbon atoms) and the like. The ring to be formed is preferably a three-to ten-membered ring in which 1 ring including the sulfur atom in the formula in the ring skeleton includes a sulfur atom, and particularly preferably a five-to seven-membered ring. Specific examples of the ring to be formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

R²⁰⁸～R²⁰⁹Each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, in R²⁰⁸～R²⁰⁹In the case of an alkyl group, they may be bonded to each other to form a ring.

R²¹⁰Is an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or a-SO-containing group which may have a substituent₂-a cyclic group.

As R²¹⁰Examples of the aryl group in (1) include unsubstituted aryl groups having 6 to 20 carbon atoms, and preferably phenyl and naphthyl groups.

As R²¹⁰The alkyl group in (1) is a chain or cyclic alkyl group, preferably an alkyl group having 1 to 30 carbon atoms.

As R²¹⁰The alkenyl group in (1) preferably has 2 to 10 carbon atoms.

As R²¹⁰Wherein the-SO-containing group may have a substituent₂-cyclic radicals, preferably "containing-SO₂A polycyclic group ", more preferably a group represented by the above general formula (a 5-r-1).

Y²⁰¹Each independently represents an arylene group, an alkylene group or an alkenylene group.

Y²⁰¹The arylene group in (A) is exemplified by the group R in the above formula (b1-a1)¹⁰¹The aromatic hydrocarbon group in (1) is a group obtained by removing 1 hydrogen atom from an aromatic group exemplified as the aromatic hydrocarbon group.

Y²⁰¹The alkylene group and alkenylene group in (A) may be exemplified by those represented by R in the above formula (b1-a1)¹⁰¹The group represented by the chain alkyl group or the chain alkenyl group in (1) is a group obtained by removing 1 hydrogen atom.

In the formula (ca-4), x is 1 or 2.

W²⁰¹Is a linking group having a valence of (x +1), i.e., 2 or 3.

As W²⁰¹The 2-valent linking group in (a) is preferably a 2-valent hydrocarbon group which may have a substituent(s), and may be exemplified by the group similar to Ya in the above-mentioned general formula (a2-1)²¹The same 2-valent hydrocarbon group which may have a substituent. W²⁰¹The 2-valent linking group in (A) may be any of linear, branched and cyclicPreferably, it is cyclic. Among these, a group in which 2 carbonyl groups are combined at both ends of an arylene group is preferable. The arylene group includes phenylene and naphthylene, and phenylene is particularly preferable.

As W²⁰¹The 3-valent linking group in (1) may be exemplified by the groups represented by the formula W²⁰¹Wherein the 2-valent linking group is a group obtained by removing 1 hydrogen atom from the 2-valent linking group, a group obtained by further bonding the 2-valent linking group to the 2-valent linking group, or the like. As W²⁰¹The 3-valent linking group in (1) is preferably a group in which 2 carbonyl groups are bonded to an arylene group.

As the preferable cation represented by the above formula (ca-1), specifically, cations represented by the following formulae (ca-1-56) to (ca-1-71) are listed.

[ CHEM 43 ]

[ CHEM 44 ]

[ in the formula, R "²⁰¹Is a hydrogen atom or a substituent, as the substituent, and as said R²⁰¹～R²⁰⁷And R²¹⁰～R²¹²The substituents which may be present are the same as those listed above.]

Specific examples of the preferable cation represented by the formula (ca-2) include a diphenyliodonium cation and a bis (4-tert-butylphenyl) iodonium cation.

As the preferable cation represented by the above formula (ca-3), specifically, cations represented by the following formulae (ca-3-1) to (ca-3-6) are listed.

[ CHEM 45 ]

As the preferable cation represented by the above formula (ca-4), specifically, cations represented by the following formulae (ca-4-1) to (ca-4-2) are listed.

[ CHEM 46 ]

Of the above, the cation portion ((M'^m+)_1/m) The cation represented by the general formula (ca-1) is preferable.

In the resist composition of the present embodiment, 1 kind of the component (B2) may be used alone, or 2 or more kinds may be used in combination.

When the resist composition contains the component (B2), the content of the component (B2) in the resist composition is preferably less than 50 parts by mass, more preferably 1 to 20 parts by mass, and still more preferably 1 to 10 parts by mass, based on 100 parts by mass of the component (a).

By setting the content of the component (B2) within the above-described preferable range, sufficient pattern formation can be performed. Further, when the components of the resist composition are dissolved in an organic solvent, a uniform solution is easily obtained, and the storage stability of the resist composition is preferably improved.

< ingredient (S) >

In the resist composition of the present embodiment, as the organic solvent component (S) ((S)) component, any component may be used as long as it is a component capable of dissolving each component to be blended to form a uniform solution, and any component may be appropriately selected from those conventionally known as solvents for chemically amplified resist compositions.

Examples of the component (S) include lactones such as γ -butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-amyl ketone, methyl isoamyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; derivatives of polyhydric alcohols such as compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, and compounds having an ether bond such as monomethyl ethers, monoethyl ethers, monopropyl ethers, monobutyl ethers, and the like of the polyhydric alcohols or the compounds having an ester bond [ among these, Propylene Glycol Monomethyl Ether Acetate (PGMEA), Propylene Glycol Monomethyl Ether (PGME) ]; cyclic ethers such as dioxane, esters such as methyl lactate, Ethyl Lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic organic solvents such as anisole, ethylbenzyl ether, methyltolyl ether, diphenyl ether, dibenzyl ether, phenetole, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, isopropyltoluene, mesitylene, and the like; dimethylsulfoxide (DMSO), and the like.

In the resist composition of the present embodiment, the component (S) may be used alone in 1 kind, or may be used as a mixed solvent of 2 or more kinds.

Among the above, PGMEA, PGME, gamma-butyrolactone, EL, and cyclohexanone are preferable as the (S) component.

In addition, a mixed solvent obtained by mixing PGMEA with a polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility of the PGMEA with the polar solvent, and the like, but is preferably in the range of 1:9 to 9:1, and more preferably in the range of 2:8 to 8: 2.

More specifically, in the case of blending EL or cyclohexanone as a polar solvent, PGMEA: the mass ratio of EL or cyclohexanone is preferably 1: 9-9: 1, more preferably 2: 8-8: 2. Further, in the case of blending PGME as a polar solvent, PGMEA: the mass ratio of PGME is preferably 1: 9-9: 1, more preferably 2: 8-8: 2. Further, a mixed solvent of PGMEA and PGME with cyclohexanone is also preferable.

In addition to the (S) component, a mixed solvent of γ -butyrolactone and at least 1 selected from PGMEA and EL is also preferable. In this case, the mixing ratio of the former to the latter is preferably 70:30 to 95:5 by mass.

In the resist composition of the present embodiment, the component (S) is used so that the solid content concentration of the resist composition becomes 30 mass% or more. That is, the solid content concentration of the resist composition is 30% by mass or more, preferably 30 to 50% by mass, and more preferably 30 to 40% by mass.

When the solid content concentration is not less than the lower limit of the above range, a thick resist film can be easily formed on the support. On the other hand, if the upper limit value of the above preferable range is not more than the upper limit value, the viscosity of the resist film can be reduced, and the coatability to the support and the like can be improved.

In the resist film composition of the present embodiment, the concentration of the polymer compound (a1) in the total solid content is preferably 90% by mass or more, more preferably 90 to 99% by mass, and still more preferably 95 to 99% by mass.

When the concentration of the component (a1) in the total solid content is equal to or higher than the lower limit of the above preferable range, a thick resist film can be easily formed.

< optional Components >

The resist composition of the present embodiment may further contain components (optional components) other than the above-described component (a), component (B), and component (S).

Examples of the optional components include the following (D) component, (E) component, and (F) component.

Component (D): ingredients of acid diffusion controlling agent

(D) The component (a) functions as a quencher (acid diffusion controller) for trapping an acid generated by exposure in the resist composition.

Examples of the component (D) include a photodegradable base (D1) (hereinafter referred to as a "component (D1)") which loses its acid diffusion controllability by decomposition by exposure, a nitrogen-containing organic compound (D2) (hereinafter referred to as a "component (D2)") which does not belong to the component (D1), and the like.

With respect to the (D1) component

When a resist pattern is formed using the resist composition containing the component (D1), the contrast between exposed portions and unexposed portions of the resist film can be improved.

The component (D1) is not particularly limited as long as it is a component which loses acid diffusion controllability by decomposition by exposure to light, and is preferably 1 or more compounds selected from the group consisting of a compound represented by the following general formula (D1-1) (hereinafter referred to as a "D1-1 component"), a compound represented by the following general formula (D1-2) (hereinafter referred to as a "D1-2 component"), and a compound represented by the following general formula (D1-3) (hereinafter referred to as a "D1-3 component").

The components (d1-1) to (d1-3) are decomposed in the exposed portion of the resist film and lose the acid diffusion controllability (basicity), and thus do not function as a quencher, but function as a quencher in the unexposed portion of the resist film.

[ CHEM 47 ]

[ in the formula, Rd¹～Rd⁴The alkyl group may be a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent. Wherein Rd in the formula (d1-2)²To the carbon atom adjacent to the S atom in (1) is not bonded with a fluorine atom. Yd¹Is a single bond or a 2-valent linking group. M is an integer of 1 or more, M^m+Each independently an m-valent organic cation.]

{ (d1-1) composition }

Anion part

In the formula (d1-1), Rd¹Examples of the substituent(s) include a cyclic group which may have a substituent(s), a linear alkyl group which may have a substituent(s), and a linear alkenyl group which may have a substituent(s), and R in the above-mentioned formula (b1-a1) are shown¹⁰¹The same groups.

Among these, as Rd¹Preferred is an aromatic hydrocarbon group which may have a substituent, an alicyclic group which may have a substituent, or a chain alkyl group which may have a substituent. Examples of the substituent which these groups may have include a hydroxyl group, an oxy group, an alkyl group, an aryl group, a fluorine atom, a fluoroalkyl group, lactone ring-containing groups represented by the above general formulae (a2-r-1) to (a2-r-7), ether bonds, ester bonds, and combinations thereof. In the case where an ether bond or an ester bond is contained as a substituent, an alkylene group may be present, and as the substituent in this case, linking groups represented by the above formulae (y-al-1) to (y-al-5) are preferred.

As the aromatic hydrocarbon group, a phenyl group or a naphthyl group is more preferable.

The alicyclic group is more preferably a group obtained by removing 1 or more hydrogen atoms from a polycyclic alkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like.

The chain alkyl group preferably has 1 to 10 carbon atoms, and specifically includes a linear alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; branched alkyl groups such as 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl and 4-methylpentyl.

When the chain alkyl group is a fluoroalkyl group having a fluorine atom or a fluoroalkyl group as a substituent, the number of carbon atoms in the fluoroalkyl group is preferably 1 to 11, more preferably 1 to 8, and still more preferably 1 to 4. The fluoroalkyl group may contain an atom other than a fluorine atom. Examples of the atom other than the fluorine atom include an oxygen atom, a sulfur atom, and a nitrogen atom.

As Rd¹The fluoroalkyl group is preferably a fluoroalkyl group in which a part or all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms, and particularly preferably a fluoroalkyl group (linear perfluoroalkyl group) in which all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms.

Preferred specific examples of the anion portion of the component (d1-1) are shown below.

[ CHEM 48 ]

Cation part

In the formula (d1-1), M^m+Is an organic cation with a valence of m.

As M^m+The organic cation of (c) may preferably be the same as the cations represented by the general formulae (ca-1) to (ca-4), more preferably represented by the general formula (ca-1), and still more preferably represented by the general formulae (ca-1-1) to (ca-1-71).

The component (d1-1) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

{ (d1-2) composition }

Anion part

In the formula (d1-2), Rd²Examples of the substituent(s) include a cyclic group which may have a substituent(s), a linear alkyl group which may have a substituent(s), and a linear alkenyl group which may have a substituent(s), and R in the above formula (b-a1)¹⁰¹The same groups.

Wherein, Rd²The carbon atom adjacent to the S atom in (1) is not bonded with a fluorine atom (fluorine-free substitution). Thus, the anion of the component (D1-2) becomes a moderately weak acid anion, and the quenching ability as the component (D) is improved.

As Rd²Preferred is a chain alkyl group which may have a substituent, or an alicyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 3 to 10 carbon atoms. More preferred examples of the alicyclic group include groups (which may have a substituent) obtained by removing 1 or more hydrogen atoms from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like; groups obtained by removing 1 or more hydrogen atoms from camphor and the like.

Rd²The hydrocarbon group (C) may have a substituent, and examples of the substituent include Rd of the formula (d1-1)¹The hydrocarbon group (aromatic hydrocarbon group, alicyclic group, or chain alkyl group) in (1) may have the same substituent.

Preferred specific examples of the anion portion of the component (d1-2) are shown below.

[ CHEM 49 ]

Cation part

In the formula (d1-2), M^m+Is an organic cation having a valence of M, with M in said formula (d1-1)^m+The same is true.

The component (d1-2) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

{ (d1-3) composition }

Anion part

In the formula (d1-3), Rd³Examples of the substituent(s) include a cyclic group which may have a substituent(s), a linear alkyl group which may have a substituent(s), and a linear alkenyl group which may have a substituent(s), and R in the above-mentioned formula (b1-a1)¹⁰¹The same group is preferably a cyclic group, a linear alkyl group, or a linear alkenyl group containing a fluorine atom. Among them, fluoroalkyl group is preferable, and Rd is more preferable¹The fluoroalkyl group of (a) is the same group.

In the formula (d1-3), Rd⁴Examples of the substituent(s) include a cyclic group which may have a substituent(s), a linear alkyl group which may have a substituent(s), and a linear alkenyl group which may have a substituent(s), and R in the above-mentioned formula (b1-a1)¹⁰¹The same groups.

Among them, preferred are alkyl groups, alkoxy groups, alkenyl groups, and cyclic groups which may have a substituent.

Rd⁴The alkyl group in (3) is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. Rd⁴A part of the hydrogen atoms of the alkyl group of (2) may be substituted by a hydroxyl group, a cyano group or the like.

Rd⁴The alkoxy group in (1) to (5) is preferably an alkoxy group having 1 to (5) carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a tert-butoxy group. Among them, methoxy group and ethoxy group are preferable.

Rd⁴The alkenyl group in (b) is exemplified by the same as R in the above formula (b1-a1)¹⁰¹The same groups are preferably vinyl, propenyl (allyl), 1-methylpropenyl and 2-methylpropenyl. These groups may further have an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms as a substituent。

Rd⁴The cyclic group in (b) is exemplified by the group R in the above formula (b1-a1)¹⁰¹The same groups are preferably alicyclic groups obtained by removing 1 or more hydrogen atoms from cycloalkanes such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane and tetracyclododecane, or aromatic groups such as phenyl and naphthyl. At Rd⁴In the case of an alicyclic group, the resist composition is well dissolved in an organic solvent, and thus the lithographic characteristics are good. Furthermore, at Rd⁴In the case of an aromatic group, the resist composition is excellent in light absorption efficiency, sensitivity and lithographic characteristics.

In the formula (d1-3), Yd¹Is a single bond or a 2-valent linking group.

As Yd¹The 2-valent linking group in (2) is not particularly limited, and examples thereof include a 2-valent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent, a 2-valent linking group containing a hetero atom, and the like. These may be exemplified by Ya in the general formula (a10-1) mentioned above^x1The 2-valent hydrocarbon group which may have a substituent and the same group as the 2-valent linking group containing a hetero atom are listed in the description of the 2-valent linking group in (1).

As Yd¹Preferably a carbonyl group, ester linkage, amide linkage, alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, and still more preferably a methylene group or an ethylene group.

Preferred specific examples of the anion portion of the component (d1-3) are shown below.

[ CHEM 50 ]

[ CHEM 51 ]

Cation part

In the formula (d1-3), M^m+Is an organic cation having a valence of M, with M in said formula (d1-1)^m+The same is true.

The component (d1-3) may be used alone in 1 kind or in combination of 2 or more kinds.

(D1) The component (c) may be any of the above-mentioned components (d1-1) to (d1-3), or 2 or more thereof may be used in combination.

When the resist composition contains the component (D1), the content of the component (D1) in the resist composition is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and still more preferably 1 to 8 parts by mass, based on 100 parts by mass of the component (A).

When the content of the component (D1) is not less than the lower limit of the above preferable range, particularly good lithographic characteristics and resist pattern shape can be easily obtained. On the other hand, if the upper limit of the preferable range is not more than the upper limit, the sensitivity can be maintained well, and the productivity is excellent.

With respect to the (D2) component

The acid diffusion-controlling agent component may contain a nitrogen-containing organic compound component (hereinafter referred to as the "component D2") other than the above-mentioned component D1.

The component (D2) is not particularly limited as long as it functions as an acid diffusion controller and does not belong to the component (D1), and any known component may be used. Among them, aliphatic amines are preferable, and among them, secondary aliphatic amines and tertiary aliphatic amines are particularly more preferable.

The aliphatic amine is an amine having 1 or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms.

As the aliphatic amine, ammonia NH may be mentioned₃An amine (alkylamine or alkylol amine) or a cyclic amine obtained by substituting at least 1 of the hydrogen atoms of (a) a hydrocarbon group of 12 or less with an alkyl group or a hydroxyalkyl group.

Specific examples of the alkylamine and the alkylol amine include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine (tripentylamine), tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkylolamines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine and tri-n-octanolamine. Among these, trialkylamines having 5 to 10 carbon atoms are more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be a monocyclic compound (aliphatic monocyclic amine) or a polycyclic compound (aliphatic polycyclic amine).

Specific examples of the alicyclic monocyclic amine include piperidine and piperazine.

The aliphatic polycyclic amine preferably has 6 to 10 carbon atoms, and specifically includes 1, 5-diazabicyclo [4.3.0] -5-nonene, 1, 8-diazabicyclo [5.4.0] -7-undecene, hexamethylenetetramine, 1, 4-diazabicyclo [2.2.2] octane and the like.

Examples of the other aliphatic amines include tris (2-methoxymethoxyethyl) amine, tris {2- (2-methoxyethoxy) ethyl } amine, tris {2- (2-methoxyethoxymethoxy) ethyl } amine, tris {2- (1-methoxyethoxy) ethyl } amine, tris {2- (1-ethoxyethoxy) ethyl } amine, tris {2- (1-ethoxypropoxy) ethyl } amine, tris [2- {2- (2-hydroxyethoxy) ethoxy } ethyl ] amine, and triethanolamine triacetate is preferred.

As the component (D2), an aromatic amine can be used.

Examples of the aromatic amine include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2, 6-diisopropylaniline, and n-tert-butoxycarbonylpyrrolidine.

(D2) The component (A) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

When the resist composition contains the component (D2), the content of the component (D2) in the resist composition is usually 0.01 to 5 parts by mass per 100 parts by mass of the component (A). When the content of the component (D2) is in the above-mentioned preferable range, the resist pattern shape, the stability with time during storage, and the like are improved.

(E) component: at least 1 compound selected from the group consisting of organic carboxylic acids and phosphorus oxyacids and derivatives thereof

The resist composition of the present embodiment may contain at least 1 compound (E) (hereinafter referred to as "component (E)") selected from the group consisting of organic carboxylic acids and oxyacids of phosphorus and derivatives thereof as an optional component for the purpose of preventing sensitivity deterioration, improving resist pattern shape, stability with time after leaving, and the like.

As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are preferable.

The oxyacid of phosphorus includes phosphoric acid, phosphonic acid, phosphinic acid, and the like, and among these, phosphonic acid is particularly preferable.

Examples of the derivative of an oxyacid of phosphorus include esters obtained by substituting a hydrogen atom of the oxyacid with a hydrocarbon group, and examples of the hydrocarbon group include an alkyl group having 1 to 5 carbon atoms and an aryl group having 6 to 15 carbon atoms.

Examples of the phosphoric acid derivative include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.

Examples of the derivative of phosphonic acid include phosphonic acid esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate.

The phosphinic acid derivative includes phosphinic acid esters and phenylphosphinic acid.

In the resist composition of the present embodiment, 1 kind of the component (E) may be used alone, or 2 or more kinds may be used in combination.

When the resist composition contains the component (E), the content of the component (E) is preferably in the range of 0.01 to 5 parts by mass per 100 parts by mass of the component (a).

Component (F): fluorine additive ingredient

The resist composition of the present embodiment may contain a fluorine additive component (hereinafter referred to as "component (F)") in order to impart water repellency to a resist film or to improve lithographic characteristics.

As the component (F), for example, fluorine-containing polymer compounds described in Japanese patent application laid-open Nos. 2010-002870, 2010-032994, 2010-277043, 2011-13569 and 2011-128226 can be used.

More specifically, the component (F) is a polymer having a structural unit (F1) represented by the following formula (F1-1). As the polymer, a polymer (homopolymer) composed only of a structural unit (f1) represented by the following formula (f1-1) is preferable; a copolymer of the structural unit (f1) and the structural unit (a 1); the structural unit (f1), a structural unit derived from acrylic acid or methacrylic acid, and a copolymer of the structural unit (a 1). The structural unit (a1) copolymerized with the structural unit (f1) is preferably a structural unit derived from 1-ethyl-1-cyclooctyl (meth) acrylate or a structural unit derived from 1-methyl-1-adamantyl (meth) acrylate.

[ CHEM 52 ]

[ wherein R is the same as above, Rf¹⁰²And Rf¹⁰³Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms, Rf¹⁰²And Rf¹⁰³May be the same or different. nf¹Is an integer of 1 to 5, Rf¹⁰¹Is an organic group containing a fluorine atom.]

In the formula (f1-1), R bonded to the carbon atom at the α -position is the same as described above. As R, a hydrogen atom or a methyl group is preferable.

In the formula (f1-1), as Rf¹⁰²And Rf¹⁰³Examples of the halogen atom of (2) include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the likeParticularly, a fluorine atom is preferable. As Rf¹⁰²And Rf¹⁰³Examples of the alkyl group having 1 to 5 carbon atoms in (b) include the same ones as those of the alkyl group having 1 to 5 carbon atoms in R, and a methyl group or an ethyl group is preferable. As Rf¹⁰²And Rf¹⁰³The halogenated alkyl group having 1 to 5 carbon atoms in (b) includes, specifically, a group in which hydrogen atoms of an alkyl group having 1 to 5 carbon atoms are partially or entirely substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and a fluorine atom is particularly preferable. Wherein as Rf¹⁰²And Rf¹⁰³The alkyl group is preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, and is preferably a hydrogen atom, a fluorine atom, a methyl group or an ethyl group.

In the formula (f1-1), nf¹Is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2.

In the formula (f1-1), Rf¹⁰¹Is an organic group containing a fluorine atom, preferably a hydrocarbon group containing a fluorine atom.

The hydrocarbon group containing a fluorine atom may be any of linear, branched or cyclic, and the number of carbon atoms is preferably 1 to 20, more preferably 1 to 15, and particularly preferably 1 to 10.

The hydrocarbon group containing a fluorine atom is preferably fluorinated in an amount of 25% or more, more preferably 50% or more, of the hydrogen atoms in the hydrocarbon group, and particularly preferably 60% or more, of the hydrogen atoms in the hydrocarbon group, from the viewpoint of improving the hydrophobicity of the resist film.

Wherein, as Rf¹⁰¹More preferred is a C1-6 fluorinated hydrocarbon group, and particularly preferred is a trifluoromethyl group, -CH₂-CF₃、-CH₂-CF₂-CF₃、-CH(CF₃)₂、-CH₂-CH₂-CF₃、-CH₂-CH₂-CF₂-CF₂-CF₂-CF₃。

(F) The weight average molecular weight (Mw) of the component (B) is preferably 1000 to 50000, more preferably 5000 to 40000, particularly preferably 10000 to 30000 (in terms of polystyrene based on gel permeation chromatography). When the Mw of the component (F) is not more than the upper limit of the above preferable range, the component (F) has solubility sufficient for being dissolved in a resist solvent for use as a resist, and when the Mw of the component (F) is not less than the lower limit of the above preferable range, the dry etching resistance and the cross-sectional shape of a resist pattern are excellent, and the water repellency of the surface of a resist film can be satisfactorily expressed.

(F) The molecular weight distribution (Mw/Mn) of the component (B) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, most preferably 1.2 to 2.5.

In the resist composition of the present embodiment, 1 kind of the component (F) may be used alone, or 2 or more kinds may be used in combination.

When the resist composition contains the component (F), the content of the component (F) is preferably 0.5 to 10 parts by mass per 100 parts by mass of the component (a).

The resist composition of the present embodiment may further contain additives having miscibility, for example, additional resins for improving the performance of the resist film, surfactants, dissolution inhibitors, plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like, as appropriate as desired.

(resist Pattern Forming method)

The invention of claim 2 is a resist pattern forming method, comprising: a step (i) of forming a resist film on a support by using the resist composition according to claim 1; a step (ii) of exposing the resist film; and (iii) developing the exposed resist film to form a resist pattern.

As an embodiment of the above-described resist pattern forming method, for example, a resist pattern forming method performed as described below can be exemplified.

Step (i):

first, the resist composition of the above embodiment is applied to a support by a spin coater or the like, and is subjected to a baking (pre-bake) treatment at a temperature of 80 to 150 ℃ for 40 to 120 seconds, preferably 60 to 90 seconds, to form a resist film.

Step (ii):

next, the resist film is selectively exposed through a mask (mask pattern) having a predetermined pattern formed thereon by exposure using an exposure apparatus such as a KrF exposure apparatus, and then subjected to baking (post exposure baking (PEB)) at a temperature of 80 to 150 ℃ for 40 to 120 seconds, preferably 60 to 90 seconds.

Step (iii):

next, the resist film is subjected to a development process. The development treatment is performed using an alkaline developer in the case of an alkaline development process, and is performed using an organic solvent-containing developer (organic developer) in the case of a solvent development process.

After the development treatment, a cleaning treatment is preferably performed. The cleaning treatment is preferably water cleaning using pure water in the case of an alkaline development process, and is preferably cleaning liquid containing an organic solvent in the case of a solvent development process.

In the case of the solvent development process, after the development treatment or the cleaning treatment, a treatment of removing the developing solution or the cleaning solution attached to the pattern by the supercritical fluid may be performed.

Drying is performed after the development treatment or after the cleaning treatment. Further, a baking treatment (post-baking) may be performed after the above-described developing treatment according to circumstances. Here, the baking treatment (post-baking) is performed, for example, at a temperature of 180 ℃ or higher, preferably 180 to 200 ℃ for 40 to 120 seconds, preferably 60 to 90 seconds.

As described above, a resist pattern can be formed.

The support is not particularly limited, and conventionally known supports can be used, and examples thereof include a substrate for electronic components, a support having a predetermined wiring pattern formed thereon, and the like. More specifically, silicon wafers, substrates made of metal such as copper, chromium, iron, and aluminum, glass substrates, and the like can be cited. As a material of the wiring pattern, for example, copper, aluminum, nickel, gold, or the like can be used.

The support may be one in which an inorganic and/or organic film is provided on the substrate as described above. As the inorganic film, an inorganic anti-reflection film (inorganic BARC) can be cited. Examples of the organic film include organic films such as an organic anti-reflection film (organic BARC) and an underlying organic film in a multilayer resist method.

Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and patterning of the lower organic film is performed using a resist pattern formed on the upper resist film as a mask, and a pattern with a high aspect ratio can be formed. That is, according to the multilayer resist method, a desired thickness can be secured by the lower organic film, and therefore, the resist film can be thinned, and a fine pattern with a high aspect ratio can be formed.

The multilayer resist method is basically classified into a method (2-layer resist method) using a two-layer structure of an upper resist film and a lower organic film; and a method (3-layer resist method) of a multilayer structure of three or more layers in which one or more intermediate layers (metal thin films and the like) are provided between an upper resist film and a lower organic film.

The resist pattern forming method according to the embodiment is a method useful for forming a thick resist film. The thickness of the resist film formed in the step (i) is, for example, 1 to 10 μm, and in this range, the thickness is preferably 6 μm or more, more preferably 7 μm or more, and particularly preferably 8 μm or more, so that a resist pattern can be stably formed in a good shape.

The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F excimer laser, and the like can be used₂Excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, and the like.

The resist composition according to claim 1 is highly useful as a KrF excimer laser, an ArF excimer laser, EB or EUV laser, is more useful as a KrF excimer laser or an ArF excimer laser, and is particularly useful as a KrF excimer laser. The resist pattern forming method according to claim 2 is particularly preferable when KrF excimer laser light is irradiated to the resist film in the step (ii).

The resist film may be exposed to normal light in an inert gas such as air or nitrogen (dry exposure) or may be subjected to Liquid Immersion exposure (Liquid Immersion Lithography).

The liquid immersion exposure is an exposure method in which a space between a resist film and a lens at the lowermost position of an exposure apparatus is filled with a solvent (liquid immersion medium) having a refractive index larger than that of air in advance, and exposure is performed in this state (immersion exposure).

The immersion medium is preferably a solvent having a refractive index higher than that of air and lower than that of the resist film to be exposed. The refractive index of the solvent is not particularly limited if it is within the above range.

Examples of the solvent having a refractive index higher than that of air and lower than that of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.

Specific examples of the fluorine-based inert liquid include C₃HCl₂F₅、C₄F₉OCH₃、C₄F₉OC₂H₅、C₅H₃F₇And liquids containing a fluorine-based compound as a main component, preferably a liquid having a boiling point of 70 to 180 ℃, more preferably a liquid having a boiling point of 80 to 160 ℃. When the fluorine-based inert liquid has a boiling point in the above range, it is preferable because the medium used in the immersion liquid can be removed by a simple method after the end of exposure.

As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted by fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include perfluoroalkyl ether compounds and perfluoroalkyl amine compounds.

More specifically, the perfluoroalkyl ether compound may be perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ℃ C.), and the perfluoroalkyl amine compound may be perfluorotributylamine (boiling point: 174 ℃ C.).

As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility, and the like.

The alkaline developer used for the development treatment in the alkaline development process may be, for example, a 0.1 to 10 mass% aqueous tetramethylammonium hydroxide (TMAH) solution.

The organic solvent contained in the organic developer used for the development treatment in the solvent development process may be selected from known organic solvents as long as it is an organic solvent capable of dissolving the component (a) (component (a) before exposure). Specific examples thereof include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, and hydrocarbon solvents.

The ketone solvent is an organic solvent containing C — C (═ O) -C in the structure. The ester solvent is an organic solvent containing C — C (═ O) -O — C in the structure. The alcohol solvent is an organic solvent containing alcoholic hydroxyl groups in the structure. "Alcoholic hydroxyl group" means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. Nitrile solvents are organic solvents that contain nitrile groups in the structure. The amide-based solvent is an organic solvent containing an amide group in the structure. The ether solvent is an organic solvent containing C-O-C in the structure.

Among the organic solvents, there are also organic solvents having a structure containing a plurality of functional groups that are characteristic of the respective solvents, and in this case, the organic solvents are classified into all kinds of solvents having the functional groups at the same time. For example, diethylene glycol monomethyl ether also belongs to the above-mentioned classes of alcoholic solvents or etheric solvents.

The hydrocarbon solvent is a hydrocarbon solvent composed of a halogenated hydrocarbon and having no substituent other than a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and a fluorine atom is preferable.

Among the above, the organic solvent contained in the organic developer is preferably a polar solvent, and more preferably a ketone solvent, an ester solvent, a nitrile solvent, or the like.

Examples of the ketone solvent include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methylethyl ketone, methylisobutyl ketone, acetylacetone, diacetone, ionone, diacetone alcohol, acetyl methanol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, γ -butyrolactone, and methyl amyl ketone (2-heptanone). Among these, methyl amyl ketone (2-heptanone) is preferred as the ketone solvent.

Examples of the ester solvent include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl, Propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl carbonate, butyl carbonate, methyl pyruvate, methyl acetate, ethyl formate, butyl formate, ethyl lactate, butyl acetate, ethyl formate, butyl formate, methyl pyruvate, ethyl, Ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, and the like. Among these, butyl acetate is preferable as the ester solvent.

Examples of the nitrile solvent include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

The organic developer may be blended with known additives as needed. Examples of the additive include surfactants. The surfactant is not particularly limited, and for example, an ionic or nonionic fluorine-based and/or silicon-based surfactant can be used. The surfactant is preferably a nonionic surfactant, more preferably a nonionic fluorine-based surfactant or a nonionic silicon-based surfactant.

When the surfactant is blended, the blending amount thereof is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, based on the total amount of the organic developer.

The developing treatment can be carried out by a known developing method, and examples thereof include a method of immersing the support in a developer for a certain period of time (immersion method), a method of supporting the developer on the surface of the support by surface tension and standing for a certain period of time (stirring (paddle) method), a method of spraying the developer on the surface of the support (spray method), and a method of continuously discharging the developer onto the support rotating at a certain speed while scanning a developer discharge nozzle at a certain speed (dynamic dispensing method).

As the organic solvent contained in the cleaning liquid used for the cleaning treatment after the development treatment in the solvent development process, for example, an organic solvent which is less likely to dissolve the resist pattern among the organic solvents listed as the organic solvents used for the organic developer can be appropriately selected and used. At least 1 solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is generally used. Among these, at least 1 kind selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, and amide solvents is preferable, at least 1 kind selected from alcohol solvents and ester solvents is more preferable, and alcohol solvents are particularly preferable.

The alcohol solvent used in the cleaning solution is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be linear, branched or cyclic. Specific examples thereof include 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, and benzyl alcohol. Among these, 1-hexanol, 2-heptanol, and 2-hexanol are preferred, and 1-hexanol and 2-hexanol are more preferred.

These organic solvents may be used alone, or 2 or more kinds may be used in combination. Further, the solvent may be used in combination with an organic solvent or water other than those mentioned above. However, in consideration of the developing property, the amount of water to be mixed in the cleaning liquid is preferably 30% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, and particularly preferably 3% by mass or less, based on the total amount of the cleaning liquid.

The cleaning liquid may contain known additives as needed. Examples of the additive include surfactants. Examples of the surfactant include the same surfactants as described above, preferably nonionic surfactants, more preferably nonionic fluorine surfactants, or nonionic silicon surfactants.

When the surfactant is blended, the blending amount thereof is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, based on the total amount of the cleaning liquid.

The cleaning treatment (cleaning treatment) using the cleaning liquid can be performed by a known cleaning method. Examples of the method of the cleaning treatment include a method of continuously discharging a cleaning liquid onto a support rotating at a constant speed (spin coating method), a method of immersing the support in a cleaning liquid for a constant period of time (immersion method), and a method of spraying a cleaning liquid onto the surface of the support (spray method).

The resist pattern forming method of the present embodiment described above includes: a polymer compound (a1) having a structural unit (a10) and a structural unit (a 1); an acid generator (B1) having a cationic portion with a specific structure, wherein the concentration of the solid content in the resist composition is 30 mass% or more.

In addition, in the formation of a resist pattern using a resist composition having a total concentration of the component (a1) and the component (B1) of 30 mass% or more as a solid content, even when a resist pattern is formed by forming a thick resist film, for example, uniformity of pattern dimensions can be improved, and the resist pattern has excellent lithographic characteristics. Further, the coating property to the support is also good, and a resist film having a uniform thickness can be easily formed. Further, foaming from the resist pattern during high-temperature baking, which has been a problem in the past, can be suppressed. As described above, according to the resist composition of the present embodiment, a thick resist pattern can be stably formed in a good shape.

The resist composition and the method for forming a resist pattern are useful, for example, in applications where a thick resist film is required. The resist composition and the resist pattern forming method are useful for processing a multilayer stepped structure, and the application of the present invention enables stacking of memory films with high accuracy (manufacturing of 3-dimensional, large-capacity memories).

[ examples ] A method for producing a compound

The present invention will be described in further detail with reference to examples below, but the present invention is not limited to these examples.

< preparation of resist composition >

(example 1, comparative examples 1 to 4)

Each component shown in table 1 was mixed with a mixed solvent (propylene glycol monomethyl ether/propylene glycol monomethyl ether acetate: 8/2 (mass ratio)) and dissolved to prepare a resist composition of each example, and the concentration of the solid content in the resist composition of each example is shown in table 1.

[ TABLE 1]

In table 1, the abbreviations have the following meanings. [] The numerical values in (b) are amounts (parts by mass) to be blended.

(A) -1: a polymer compound represented by the following chemical formula (A1-1). The weight average molecular weight (Mw) calculated by GPC measurement as polystyrene standard was 10000, and the molecular weight distribution (Mw/Mn) was 1.8. By passing¹³Copolymerization composition ratio (each structural unit in the structural formula)The ratio of elements (molar ratio)) was l/m/n 60/20/20.

(A) -2: a polymer compound represented by the following chemical formula (A1-2). The weight average molecular weight (Mw) calculated by GPC measurement as polystyrene standard was 2000, and the molecular weight distribution (Mw/Mn) was 1.8. By passing¹³The copolymerization composition ratio (the ratio of the respective structural units in the structural formula (molar ratio)) determined by C-NMR was 60/20/20.

[ CHEM 53 ]

(B1) -1: a compound represented by the following chemical formula (B1-1).

(B2) -1: a compound represented by the following chemical formula (B2-1).

(B2) -2: n- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2, 3-dicarboximide

[ CHEM 54 ]

(D) -1: tripentylamine.

(E) -1: phenyl phosphonic acid.

< formation of resist Pattern >

Step (i):

an organic antireflection film composition "DUV-42P" (trade name, manufactured by Brewer science) was applied to an 8-inch silicon wafer by a spin coater, and the resultant was baked at 180 ℃ for 60 seconds on a hot plate and dried to form an organic antireflection film having a film thickness of 65 nm.

The resist compositions of the examples were applied to the organic anti-reflective coating film by using a spin coater, and dried by Prebaking (PAB) treatment at 140 ℃ for 90 seconds on a hot plate, thereby forming a resist film having a thickness of 8 μm.

In addition, in the case of using the resist composition of comparative example 4, since a resist film having a thickness of 8 μm could not be formed, the subsequent operation was not performed.

Step (ii):

next, the resist film was selectively irradiated with KrF excimer laser light (248nm) at an optimum exposure amount (Eop) for each resist composition through a mask pattern (6% halftone) by a KrF exposure apparatus NSR-S205C (manufactured by nikon, inc.; NA (numerical aperture): 0.68, σ ═ 0.60).

Then, a post-exposure heating (PEB) treatment was performed at 115 ℃ for 90 seconds.

Step (iii):

next, alkaline development was carried out at 23 ℃ for 60 seconds using 2.38 mass% aqueous tetramethylammonium hydroxide (TMAH) solution "NMD-3" (trade name, manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a developer.

Then, the sheet was washed with water for 30 seconds using pure water, and then dried by spin drying.

In the results of the above < formation of resist pattern >, in any of the examples (example 1, comparative examples 1 to 3), the space and line patterns (hereinafter referred to as "SL patterns") having the space width of 3.75 μm and the gap width of 7.5 μm were formed in the resist film.

[ evaluation of dimensional uniformity (CDU) in the surface of the support (Shot) ]

The SL pattern was observed from above by a length measuring SEM (scanning Electron microscope, acceleration Voltage 300V, trade name: S-9380, manufactured by Hitachi Hipposhu Co., Ltd.) and the width of the space in the SL pattern was measured. A 3-fold value (3 σ) of the standard deviation (σ) calculated from the measurement results was obtained, and the dimensional uniformity (CDU) in the support surface (Shot) was evaluated according to the following evaluation criteria. The evaluation results are shown in table 2 as "CDU".

Evaluation criteria:

◎ the 3 sigma is below 15 nm.

○ the 3 sigma is more than 15nm and less than 20 nm.

X3. sigma. exceeds 20 nm.

The smaller the value of 3 σ thus obtained, the higher the uniformity of the dimension (CD) of the space width formed on the resist film.

[ evaluation of film thickness uniformity in the surface of the support (Shot) ]

In the above "evaluation of dimensional uniformity (CDU) in the surface of the support (Shot)", the resist compositions of example 1, comparative example 1, and comparative example 3, which had good results, were evaluated for the film thickness uniformity of the resist film having a film thickness of 8 μm after the Prebaking (PAB) treatment in the step (i) < formation of resist pattern > in the following manner.

The film thickness (□) of the resist film was measured at 10 places (equal intervals) between both ends of the diameter of the silicon wafer using NanoSpec7001-0066XPW (manufactured by Nanometrics JAPAN Co.), and the uniformity of the film thickness in the surface of the support (Shot) was evaluated according to the following evaluation criteria. The evaluation results are shown in table 2 as "film thickness uniformity".

Evaluation criteria

○, high uniformity of film thickness (when the difference of film thickness in Shot is + -25 nm or less).

X: the uniformity of the film thickness was low (when the difference in film thickness in Shot exceeded ± 25 nm).

[ evaluation of the presence or absence of foaming ]

The resist compositions of example 1 and comparative example 1, which showed good results in the above-described [ evaluation of film thickness uniformity ], were subjected to spin-drying after the steps (i), (ii) and (iii) in the above-described < formation of resist pattern >, and further heated at 180 ℃ for 60 seconds (post-baking), and then visually evaluated for the presence or absence of foaming from the resist pattern. The results are shown in table 2 as "presence or absence of foaming".

[ TABLE 2]

From the results shown in table 2, it was confirmed that when a resist pattern was formed using the resist composition of example 1 to which the present invention was applied, the resist pattern was excellent in lithographic characteristics and good in coatability, and foaming from the resist pattern during high-temperature baking was suppressed.

Claims

1. A resist composition which generates an acid upon exposure and whose solubility in a developer changes by the action of the acid, characterized by comprising:

a polymer compound (A1) having a structural unit (a10) represented by the following general formula (a10-1) and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid; an acid generator (B1) represented by the following general formula (B1),

the solid content concentration in the resist composition is 30 mass% or more;

[ CHEM 1]

Wherein R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms; ya^x1Is a single bond or a 2-valent linking group; wa^x1Is (n)_ax1+1) a valent aromatic hydrocarbon group; n is_ax1Is an integer of 1 to 3; r²⁰¹¹、R²⁰²¹And R²⁰³¹Each independently represents an aryl group which may have a substituent; r²⁰¹¹、R²⁰²¹And R²⁰³¹2 or more of them may be bonded to each other to form a ring together with the sulfur atom in the formula; x^-Denotes a counter anion.

2. The resist composition of claim 1,

r in the general formula (b1)²⁰¹¹、R²⁰²¹And R²⁰³¹At least 1 of which is an aryl group having a substituent,

the substituent is 1 or more selected from the group consisting of alkyl group, halogen atom, haloalkyl group, carbonyl group, cyano group, amino group, aryl group, and groups represented by the following general formulae (ca-r-1) to (ca-r-7);

[ CHEM 2]

In the formula (II), R'²⁰¹Each independently represents a hydrogen atom, a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent.

3. The resist composition according to claim 1 or 2, wherein the concentration of the polymer compound (a1) in the entire solid content of the resist composition is 90% by mass or more.

4. The resist composition according to any one of claims 1 to 3, wherein the high molecular compound (A1) has a weight average molecular weight of 5000 to 20000.

5. A method for forming a resist pattern, comprising:

a step (i) of forming a resist film on a support by using the resist composition according to any one of claims 1 to 4;

a step (ii) of exposing the resist film;

and (iii) developing the exposed resist film to form a resist pattern.

6. The method of forming a resist pattern according to claim 5, wherein in the step (ii), the resist film is irradiated with KrF excimer laser light.