KR102611582B1 - Resist composition and method of forming resist pattern using the same - Google Patents

Abstract

The present invention provides a resist composition comprising a component (A) whose solubility in a developer changes by the action of an acid and an acid generator component (B) which generates an acid upon exposure, wherein the component (A) is a structural unit. It relates to a resist composition and a resist pattern formation method containing a polymer compound (A1) having (a1) and a structural unit (af) containing a fluorine atom.
According to the present invention, a resist composition capable of forming a resist pattern with improved in-plane uniformity (CDU) of pattern dimensions while simultaneously reducing the problem of dissolution during liquid immersion exposure, and a resist pattern using the resist composition A formation method may be provided.

Description

Resist composition and method of forming a resist pattern using the same {RESIST COMPOSITION AND METHOD OF FORMING RESIST PATTERN USING THE SAME}

The present invention relates to a resist composition and a method of forming a resist pattern using the resist composition.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, the resist film is selectively exposed to radiation such as light or electron beam through a mask on which a predetermined pattern is formed, and development is performed. , a process of forming a resist pattern of a predetermined shape on the resist film is performed.

As exposure light sources become shorter in wavelength, resist materials are required to have improved lithography characteristics, such as sensitivity to exposure light sources and resolution capable of reproducing fine-dimensional patterns. As a resist material that satisfies these requirements, a chemically amplified resist composition containing a base component (base resin) whose solubility in a developer changes due to the action of acid and an acid generator component that generates acid upon exposure is used. It is becoming.

For example, when the developer is an alkaline developer (alkaline development process), the positive-type chemically amplified resist composition includes a resin component (base resin) whose solubility in the alkaline developer increases by the action of an acid, and an acid generator. Those containing the ingredient are commonly used.

When a resist film formed using such a resist composition is subjected to selective exposure during resist pattern formation, acid is generated from the acid generator component in the exposed area, and the polarity of the base resin increases due to the action of the acid, The exposed area is soluble in alkaline developer. Therefore, through alkali development, a positive pattern is formed in which the unexposed portion remains as a pattern.

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), as the polarity of the base resin increases, the solubility in the organic developer relatively decreases, The unexposed portion of the resist film is dissolved and removed by an organic developer, forming a negative resist pattern in which the exposed portion remains as a pattern. The solvent development process that forms a negative resist pattern in this way is called a negative development process.

In order to provide high resolution and a good pattern shape in the formation of a resist pattern, a methacrylic repeating unit containing adamantyl on the tertiary carbon as an acid labile group and a methacrylic repeating unit in which the tertiary carbon forms a cyclic structure are used. It is known to use a positive resist composition containing a resin whose alkali solubility is improved by acid, a photoacid generator, and a solvent (see, for example, Patent Document 1).

Since conventional resist compositions do not form sufficiently uniform patterns, as the refinement of patterns further progresses, the demand for polymer compounds useful as base resins for resist compositions is increasing.

As one of the methods to further improve resolution, a lithography method in which exposure (immersion exposure) is performed by interposing a liquid (liquid immersion medium) with a higher refractive index than air between the objective lens of the exposure machine and the sample, so-called liquid immersion lithography ( Liquid Immersion Lithography (hereinafter sometimes referred to as liquid immersion exposure) is known (see, for example, Non-Patent Document 1).

According to liquid immersion exposure, even when a light source with the same exposure wavelength is used, the same high resolution can be achieved as when a light source with a shorter wavelength or a high NA lens is used, and it is believed that there is no decrease in the depth of focus. Additionally, immersion exposure can be performed using existing exposure equipment. Therefore, immersion lithography is expected to be able to realize the formation of a resist pattern that is low-cost, high-resolution, and has an excellent depth-of-focus width, and is suitable for both cost and resolution in the manufacture of semiconductor devices that require a large amount of equipment investment. It is attracting great attention both for its lithography characteristics and for providing enormous benefits to the semiconductor industry.

Liquid immersion exposure is effective in forming all pattern shapes, and is also believed to be possible in combination with super-resolution technologies such as the phase shift method and modified illumination method that are currently being examined. Currently, liquid immersion exposure technology using ArF excimer laser as a light source is being actively researched. Additionally, water is currently being mainly considered as an immersion medium.

In liquid immersion exposure, a resist material is required that has properties corresponding to the liquid immersion lithography technique in addition to normal lithographic properties (sensitivity, resolution, etching resistance, etc.). In liquid immersion exposure, when the resist film and the liquid immersion solvent come into contact, substances in the resist film are eluted into the liquid immersion solvent (substance elution). Material elution causes phenomena such as deterioration of the resist layer and changes in the refractive index of the immersion solvent, and deteriorates lithography characteristics. Since the amount of this material elution is affected by the properties of the resist film surface (e.g., hydrophilicity, hydrophobicity, etc.), for example, as the hydrophobicity of the resist film surface increases, the material elution may be reduced. In addition, when the liquid immersion medium is water and immersion exposure is performed using a scanning type liquid immersion exposure machine (Non-patent Document 1), the liquid immersion medium is required to have water tracking properties that move in accordance with the movement of the lens. do. If water catchability is low, exposure speed decreases, so there is concern that productivity will be affected. It is believed that this water absorption property is improved by increasing the hydrophobicity of the resist film surface (making it hydrophobized). In this way, it is believed that by increasing the hydrophobicity of the resist film surface, problems unique to the immersion exposure technology, such as reduction of material elution and improvement of water absorption, can be solved.

Recently, research and development in various fields has been actively conducted on fluorinated compounds, focusing on their properties such as water repellency and transparency.

For example, in the field of resist materials, acid-labile groups such as methoxymethyl group, tert-butyl group, and tert-butyloxycarbonyl group are currently introduced into fluorinated polymer compounds for use as base resins for positive-type chemically amplified resists. What is being done is being done. However, when such a fluorine-based polymer compound is used as a base resin for a positive resist composition, there are drawbacks such as a large amount of outgas being generated after exposure and insufficient resistance to dry etching gas (etching resistance).

Recently, as a fluorine-containing polymer compound with excellent etching resistance, a fluorine-containing polymer compound having an acid labile group containing a cyclic hydrocarbon group has been reported (see, for example, Non-Patent Document 2).

Additionally, in a resist composition for liquid immersion exposure, a fluorinated polymer compound has been reported to impart water repellency to the resist film (Non-Patent Document 3).

However, even if the resist film is merely hydrophobized, adverse effects on lithography characteristics, etc. appear. As an example, when an organic developer is used in a resist film containing a fluorinated polymer compound, the in-plane uniformity (CDU, Critical Dimension Uniformity) of the pattern dimension is impaired.

The in-plane uniformity of pattern dimensions is determined by measuring the diameter of each hole in the case of a CH (Contact Hole) pattern, calculating the average value, and calculating the standard deviation of the average value and the measured diameter of the hole. In other words, the smaller the value, the more desirable.

Therefore, there is still a need for the development of a resist composition that can obtain a resist pattern with excellent in-plane uniformity of pattern dimensions while simultaneously reducing the problem of dissolution during liquid immersion exposure.

Japanese Patent Publication No. 2003-241385

Proceedings of SPIE, Volume 5754, [0012] Pages 119-128 (2005). Proceedings of SPIE, Volume 4690, Pages 76-83 (2002). Journal of Photopolymer. Sci. Technol., Volume 19, No.4, Pages 565-568 (2006).

The present invention has been made in view of the above circumstances, and is a resist composition capable of forming a resist pattern with improved in-plane uniformity (CDU) of pattern dimensions while reducing the problem of dissolution during liquid immersion exposure, and the resist composition. The task is to provide a resist pattern formation method using .

As a result of repeated studies, the present inventors have found that the above problems can be solved when the resist composition contains a polymer compound having a specific structural unit as component (A) whose solubility in the developer changes due to the action of an acid. was discovered and the present invention was completed.

A first aspect of the present invention is a resist composition comprising a component (A) whose solubility in a developer changes by the action of an acid and an acid generator component (B) which generates an acid upon exposure,

This is a resist composition in which the component (A) contains a polymer compound having a structural unit (a1) represented by the following formula (a1-1) and a structural unit (af) containing a fluorine atom.

[Formula 1]

(a1-1)

[In formula (a1-1), R represents a hydrogen atom, an alkyl group, or a halogenated alkyl group; Z represents a single bond or an alkylene group; C _P is (Here, R ₂ is a tertiary alkyl group, n _p is a positive integer, and * indicates a bonding position).]

A second aspect of the present invention includes a process of forming a resist film on a support using the resist composition of the first aspect of the invention, exposing the resist film, and developing the resist film to form a resist pattern. A resist pattern forming method comprising:

According to the present invention, it is possible to provide a resist composition that can obtain a resist pattern with excellent in-plane uniformity of pattern dimensions while simultaneously reducing the problem of dissolution during liquid immersion exposure, and a resist pattern formation method using the resist composition. there is.

In this specification and claims,

The “hydrocarbon group” may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated.

Unless otherwise specified, “alkyl group” includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The alkyl group in the alkoxy group is the same.

Unless otherwise specified, “alkylene group” includes straight-chain, branched-chain, and cyclic divalent saturated hydrocarbon groups.

A “halogenated alkyl group” is a group in which some or all of the hydrogen atoms of an alkyl group are replaced with halogen atoms, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

“Fluorinated alkyl group” or “fluorinated alkylene group” refers to a group in which some or all of the hydrogen atoms of an alkyl group or alkylene group are replaced with fluorine atoms.

“Structural unit” means a monomer unit (monomer unit) constituting a high molecular compound (resin, polymer, copolymer).

“Constitutive unit derived from acrylic acid ester” means a structural unit formed by cleavage of the ethylenic double bond of acrylic acid ester.

“Acrylic acid ester” is a compound in which the hydrogen atom at the carboxyl group terminal of acrylic acid (CH ₂ =CH-COOH) is substituted with an organic group.

In the acrylic acid ester, the hydrogen atom bonded to the carbon atom at the α position may be substituted with a substituent. The substituent (R ^α ) that replaces the hydrogen atom bonded to the carbon atom at the α position is an atom or group other than a hydrogen atom, for example, an alkyl group with 1 to 5 carbon atoms, a halogenated alkyl group with 1 to 5 carbon atoms, a hydroxyalkyl group, etc. can be mentioned. Additionally, the carbon atom at the α position of the acrylic acid ester refers to the carbon atom to which the carbonyl group is bonded, unless otherwise specified.

Hereinafter, acrylic acid ester in which the hydrogen atom bonded to the carbon atom at the α position is replaced with a substituent may be referred to as α-substituted acrylic acid ester. In addition, acrylic acid ester and α-substituted acrylic acid ester are sometimes collectively referred to as “(α-substituted) acrylic acid ester.”

“Structural unit derived from a hydroxystyrene derivative” means a structural unit formed by cleavage of the ethylenic double bond of hydroxystyrene or a hydroxystyrene derivative.

“Hydroxystyrene derivatives” is a concept that includes those in which the hydrogen atom at the α position of hydroxystyrene is replaced with other substituents such as an alkyl group and a halogenated alkyl group, as well as derivatives thereof. Their derivatives include those in which the hydrogen atom of the hydroxyl group of hydroxystyrene, in which the hydrogen atom in the α position may be substituted with a substituent, is substituted with an organic group, and those in which the hydrogen atom in the α position is optionally substituted with a substituent in the benzene ring of hydroxystyrene with a hydroxyl group. Substituents other than those bonded together may be mentioned. Additionally, the α position (carbon atom at the α position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.

Substituents that replace the hydrogen atom at the α position of hydroxystyrene include the same substituents as those exemplified as the substituents at the α position in the α-substituted acrylic acid ester.

“Constitutive unit derived from vinylbenzoic acid or vinylbenzoic acid derivative” means a structural unit formed by cleavage of the ethylenic double bond of vinylbenzoic acid or vinylbenzoic acid derivative.

The term “vinylbenzoic acid derivative” is a concept that includes those in which the hydrogen atom at the α position of vinylbenzoic acid is replaced with other substituents such as an alkyl group and a halogenated alkyl group, as well as derivatives thereof. Their derivatives include those in which the hydrogen atom of the carboxyl group of vinylbenzoic acid, where the hydrogen atom at the α position may be substituted with a substituent, is substituted with an organic group, and those in which the hydrogen atom at the α position is optionally substituted with a substituent, in which the hydrogen atom of the carboxyl group is substituted with an organic group, and those in which the hydrogen atom at the α position is optionally substituted with a substituent, in which the hydrogen atom of the carboxyl group is replaced with an organic group, and those in which the hydrogen atom at the α position is optionally substituted with a substituent, have a hydroxyl group and a carboxyl group in the benzene ring. Substituents other than those bonded together may be mentioned. Additionally, the α position (carbon atom at the α position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.

“Styrene derivative” means that the hydrogen atom at the α position of styrene is substituted with another substituent such as an alkyl group or halogenated alkyl group.

“Structural unit derived from styrene” and “structural unit derived from styrene derivative” mean a structural unit formed by cleavage of the ethylenic double bond of styrene or a styrene derivative.

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 group, pentyl group, isopentyl group, neopentyl group), etc.

Additionally, the halogenated alkyl group as the substituent at the α position specifically includes a group in which part or all of the hydrogen atoms of the above-mentioned “alkyl group as the substituent at the α position” are replaced with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.

Moreover, the hydroxyalkyl group as the substituent at the α position specifically includes a group in which part or all of the hydrogen atoms of the above-mentioned “alkyl group as the substituent at the α position” are substituted with hydroxyl groups. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, and 1 is most preferable.

When it is stated that “it may have a substituent,” it includes both the case of replacing the hydrogen atom (-H) with a monovalent group and the case of replacing the methylene group (-CH ₂ -) with a divalent group.

“Exposure” is a concept that includes the overall irradiation of radiation.

<Resist composition>

A first aspect of the present invention is a resist composition comprising a component (A) whose solubility in a developer changes by the action of an acid and an acid generator component (B) which generates an acid upon exposure,

This is a resist composition in which the component (A) contains a polymer compound having a structural unit (a1) represented by the following formula (a1-1) and a structural unit (af) containing a fluorine atom.

[Formula 2]

(a1-1)

[In formula (a1-1), R represents a hydrogen atom, an alkyl group, or a halogenated alkyl group; Z represents a single bond or an alkylene group; C _P is (Here, R ₂ is a tertiary alkyl group, n _p is a positive integer, and * indicates a bonding position).]

In the present invention, the resist composition contains a base component (A) (hereinafter also referred to as “component (A)”) whose solubility in a developer changes due to the action of an acid.

When a resist film is formed using such a resist composition and selective exposure is performed on the resist film, acid is generated in the exposed area, and the solubility of component (A) in the developer solution changes due to the action of the acid. Since the solubility of component (A) in the developer does not change in the exposed area, a difference in solubility in the developer occurs between the exposed and unexposed areas. Therefore, when the resist film is developed, if the resist composition is a positive type, the exposed portion is dissolved and removed to form a positive resist pattern, and if the resist composition is a negative type, the unexposed portion is dissolved and removed to form a negative resist pattern. is formed

In this specification, a resist composition in which exposed areas 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 areas are dissolved and removed to form a negative resist pattern is referred to as a negative resist composition.

In the present invention, the resist composition may be a positive resist composition or a negative resist composition. Additionally, the resist composition of the present invention can be used in a dual tone development (DTD) process.

In addition, in the present invention, the resist composition may be used for an alkaline development process using an alkaline developer for the development process when forming a resist pattern, or for a solvent development process using a developer containing an organic solvent (organic developer) for the development treatment. Although it may be for a solvent development process, it is preferable that it is for a solvent development process.

The resist composition used to form the resist pattern has an acid-generating ability to generate acid upon exposure, and contains an acid generator component (B), and component (A) generates acid upon exposure. It's okay.

In the case where component (A) generates acid upon exposure, component (A) becomes “a base component that generates acid upon exposure and whose solubility in the developer changes due to the action of the acid.” When the component (A) is a base component that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, the component (A1) described later generates an acid upon exposure and also the action of the acid. It is preferable that it is a polymer compound whose solubility in the developer changes depending on the condition. As such a polymer compound, a resin having a structural unit that generates acid upon exposure can be used. Known structural units that generate acid upon exposure can be used.

<(A) component>

In the present invention, the “base component” is an organic compound having film-forming ability, and preferably an organic compound with a molecular weight of 500 or more is used. When the molecular weight of the organic compound is 500 or more, the film forming ability is improved, and in addition, it is easy to form a nano-level photosensitive resin pattern.

Organic compounds used as base components are broadly divided into non-polymers and polymers.

As a non-polymer, those having a molecular weight of 500 to 4000 are usually used. Hereinafter, when referred to as a “low molecular compound”, it refers to a non-polymer having a molecular weight of 500 or more and less than 4000.

As a polymer, a polymer having a molecular weight of 1000 or more is usually used. Hereinafter, when referring to “resin”, it refers to a polymer (high molecular compound) with a molecular weight of 1000 or more.

As the molecular weight of the polymer, the mass average molecular weight calculated in terms of polystyrene by GPC (gel permeation chromatography) is used.

As the component (A), a resin may be used, a low molecular compound may be used, or these may be used in combination.

(A) The solubility of the component in the developing solution changes due to the action of the acid.

Additionally, in the present invention, component (A) may be one that generates acid upon exposure.

In the present invention, component (A) is a polymer compound (A1) having a structural unit (hereinafter sometimes referred to as “structural unit (a1)”) containing an acid-decomposable group whose polarity increases by the action of an acid. Contains

(Constitutive unit (a1))

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

An “acid-decomposable group” is a group having acid-decomposability in which at least a portion of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid.

In the present invention, the polymer compound (A1) contained in component (A) is a structural unit (a1) containing an acid-decomposable group whose polarity increases by the action of an acid, and has a structure represented by the following formula (a1-1) Includes units.

[Formula 3]

...(a1-1)

[In formula (a1-1), R represents a hydrogen atom, an alkyl group, or a halogenated alkyl group; Z represents a single bond or an alkylene group; C _P is (Here, R ₂ is a tertiary alkyl group, n _p is a positive integer, and * indicates a bonding position).]

In the above formula (a1-1), the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, and specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, and phen. A thyl group, an isopentyl group, a neopentyl group, etc. are mentioned. The halogenated alkyl group is preferably a halogenated alkyl group having 1 to 5 carbon atoms, which is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are replaced with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.

In the above formula (a1-1), R is most preferably a hydrogen atom or a methyl group because it is easy to obtain industrially.

n _p is preferably an integer of 1 to 3, and is more preferably 1.

R ₂ is preferably a tertiary alkyl group having 4 to 10 carbon atoms, and more preferably a tert-butyl group. If R ₂ is not a tertiary alkyl group, this will cause a decrease in the in-plane uniformity (CDU) of the pattern dimensions of the resist pattern.

Z is preferably a single bond or an alkylene group having 1 to 10 carbon atoms. The alkylene group having 1 to 10 carbon atoms is preferably a linear or branched alkylene group having 1 to 10 carbon atoms, and more preferably a linear or branched alkylene group having 1 to 5 carbon atoms, specifically. Examples include methylene group, ethylene group, propylene group, isopropylene group, and n-butylene group.

As Z, a single bond or an alkylene group having 1 to 5 carbon atoms is more preferable, and a single bond is most preferable.

Preferred specific examples of the above formula (a1-1) are given below. Among these, (a1-11) is most preferable.

[Formula 4]

(a1-11) (a1-12) (a1-13) (a1-14)

In the above formulas (a1-11) to (a1-14), each R is the same as the definition of R in formula (a1-1).

In the present invention, the polymer compound (A1) contained in component (A) may further include a structural unit (a1) containing an acid-decomposable group other than the structural unit represented by the formula (a1-1).

Examples of acid-decomposable groups whose polarity increases by the action of an acid include groups that decompose by the action of an acid to produce a polar group.

Examples of polar groups include carboxyl group, hydroxyl group, amino group, and sulfonic acid group (-SO ₃ H). Among these, a sulfonic acid group or a polar group containing -OH in the structure (hereinafter sometimes referred to as "OH-containing polar group") is preferable, a sulfonic acid group, a carboxyl group, or a hydroxyl group is preferable, and a carboxyl group or a hydroxyl group is especially 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 the oxygen atom of an OH-containing polar group is protected by an acid-dissociable group).

Here, “mountain dissociation penis” means,

(i) a group having an acid dissociable property in which the bond between the acid dissociable group and an atom adjacent to the acid dissociable group can be cleaved by the action of an acid, or,

(ii) a group in which a bond between the acid dissociable group and an atom adjacent to the acid dissociable group can be cleaved by further decarboxylation reaction occurring after some of the bonds are cleaved by the action of an acid;

refers to both sides.

The acid dissociable group constituting the acid dissociable group must be a group with a lower polarity than the polar group generated by dissociation of the acid dissociable group. Therefore, when the acid dissociable group is dissociated by the action of the acid, it is necessary to be a group less polar than the acid dissociable group. A highly polar group is created and polarity increases. As a result, the polarity of all components of the polymer compound (A1) increases. As polarity increases, the solubility in the developer relatively changes, and when the developer is an organic developer, the solubility decreases.

There is no particular limitation on the acid dissociable group, and any acid dissociable group that has been proposed so far as an acid dissociable group in base resins for chemically amplified resists can be used.

Among the above polar groups, the acid dissociable group that protects the carboxyl group or the hydroxyl group is, for example, an acid dissociable group represented by the following formula (a1-r-1) (hereinafter, for convenience, it may be referred to as an “acetal-type acid dissociable group”) ) can be mentioned.

[Formula 5]

[In the formula, Ra' ¹ and Ra' ² represent a hydrogen atom or an alkyl group, Ra' ³ represents a hydrocarbon group, and Ra' ³ may be bonded to any of Ra' ¹ and Ra' ² to form a ring. * refers to the binding position.]

In formula (a1-r-1), the alkyl groups of Ra' ¹ and Ra' ² include the same alkyl groups exemplified as substituents that may be bonded to the carbon atom at the α position in the description of the α-substituted acrylic acid ester. A methyl group or an ethyl group is preferred, and a methyl group is most preferred.

The hydrocarbon group for Ra' ³ is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and a straight or branched alkyl group is preferable, and specifically, a methyl group, an ethyl group, or a propyl group. group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, 1,1-dimethylethyl group, 1,1-diethylpropyl group, 2,2 -Dimethylpropyl group, 2,2-dimethylbutyl group, etc. are mentioned.

When Ra' ³ is a cyclic hydrocarbon group, it may be aliphatic or aromatic, and may be polycyclic or monocyclic. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing one hydrogen atom from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 8 carbon atoms, and specific examples include cyclopentane, cyclohexane, and cyclooctane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one hydrogen atom from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, and isocarbon group. Bornane, tricyclodecane, tetracyclododecane, etc. can be mentioned.

When it is an aromatic hydrocarbon group, specific examples of aromatic rings included include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; an aromatic heterocycle in which some of the carbon atoms constituting the aromatic hydrocarbon ring are replaced with heteroatoms; etc. can be mentioned. Hetero atoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms.

Specifically, the aromatic hydrocarbon group includes a group obtained by removing one hydrogen atom from the aromatic hydrocarbon ring (aryl group); A group in which one of the hydrogen atoms of the aryl group is replaced with an alkylene group (e.g., benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc. arylalkyl group) ; etc. can be mentioned. 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 especially preferably 1.

When Ra' ³ combines with either Ra' ¹ or Ra' ² to form a ring, the cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include tetrahydropyranyl group and tetrahydrofuranyl group.

Among the above polar groups, examples of the acid dissociable group that protects the carboxyl group include an acid dissociable group represented by the following formula (a1-r-2).

[Formula 6]

[In the formula, Ra' ⁴ to Ra' ⁶ are hydrocarbon groups, and Ra' ⁵ and Ra' ⁶ may be bonded to each other to form a ring. * refers to the binding position.]

Hydrocarbon groups of Ra' ⁴ to Ra' ⁶ include the same hydrocarbon groups as Ra' ³ above. Ra' ⁴ is preferably an alkyl group having 1 to 5 carbon atoms. When Ra' ⁵ and Ra' ⁶ combine with each other to form a ring, a group represented by the following formula (a1-r2-1) is included.

On the other hand, when Ra' ⁴ to Ra' ⁶ are not bonded to each other and are independent hydrocarbon groups, a group represented by the following formula (a1-r2-2) can be given.

[Formula 7]

[Wherein, Ra' ¹⁰ is an alkyl group having 1 to 10 carbon atoms, Ra' ¹¹ is a group that forms an aliphatic cyclic group together with the carbon atom to which Ra' ¹⁰ is bonded, and Ra' ¹² to Ra' ¹⁴ each independently represents a hydrocarbon group. . * refers to the binding position.]

In formula (a1-r2-1), the alkyl group of the alkyl group of Ra' ¹⁰ and having 1 to 10 carbon atoms is exemplified as the straight-chain or branched alkyl group of Ra' ³ in formula (a1-r-1). Gi is preferable. In formula (a1-r2-1), the aliphatic cyclic group constituted by Ra' ¹¹ is preferably the group exemplified as the cyclic alkyl group of Ra' ³ in formula (a1-r-1).

In formula (a1-r2-2), Ra' ¹² and Ra' ¹⁴ are each independently preferably an alkyl group having 1 to 10 carbon atoms, and the alkyl group is represented by Ra' ³ in formula (a1-r-1). The groups exemplified as straight-chain or branched alkyl groups are more preferable, more preferably straight-chain alkyl groups having 1 to 5 carbon atoms, and particularly preferably methyl or ethyl groups.

In formula (a1-r2-2), Ra' ¹³ is preferably a straight-chain, branched-chain or cyclic alkyl group exemplified by the hydrocarbon group of Ra' ³ in formula (a1-r-1). . Among these, the group exemplified as the cyclic alkyl group of Ra' ³ is more preferable.

Specific examples of the above formula (a1-r2-1) are given below.

[Formula 8]

[In the formula, * refers to the binding position.]

Specific examples of the above formula (a1-r2-2) are given below.

[Formula 9]

[In the formula, * refers to the binding position.]

In addition, examples of the acid dissociable group that protects the hydroxyl group among the above polar groups include an acid dissociable group represented by the following formula (a1-r-3) (hereinafter referred to as a “tertiary alkyloxycarbonyl acid dissociable group” for convenience) There are cases where this is done).

[Formula 10]

[In the formula, Ra' ⁷ to Ra' ⁹ represent an alkyl group. * refers to the binding position.]

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

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

Examples of the structural unit having an acid-decomposable group include a structural unit derived from an acrylic acid ester in which the hydrogen atom bonded to the carbon atom at the α position may be substituted with a substituent, and containing an acid-decomposable group whose polarity increases by the action of an acid; A structural unit derived from hydroxystyrene or a hydroxystyrene derivative in which at least part of the hydrogen atoms in the hydroxyl group of the structural unit is protected by a substituent containing the acid-decomposable group; Examples include structural units derived from vinylbenzoic acid or vinylbenzoic acid derivatives in which at least part of the hydrogen atom in -C(=O)-OH is protected by a substituent containing the acid-decomposable group.

Known structural units having an acid-decomposable group other than the structural unit represented by the above formula (a1-1) can be used, but the structural unit represented by the following formula (a1-2) is preferable.

[Formula 11]

(a1-2)

[In formula (a1-2), R' represents a hydrogen atom, an alkyl group, or a halogenated alkyl group; Z' represents a single bond or an alkylene group; _Cp ' is selected from the group consisting of the above formula (a1-r-1) or (a1-r-2).]

Specifically, in the above formula (a1-2), R' and Z' are the same as the definitions of R and Z in the above formula (a1-1), respectively.

The polymer compound (A1) containing the structural unit (a1) of the present invention is a structural unit having an acid-decomposable group other than the structural unit represented by the formula (a1-1), and is represented by the following (a1-3) or (a1-4) It may additionally include a structural unit represented by .

[Formula 12]

(a1-3) (a1-4)

[Wherein, R is the same as above. Va ¹ is a divalent hydrocarbon group that may have an ether bond, a urethane bond, or an amide bond, n _a1 is 0 to 2, and Ra ¹ is one of the formulas (a1-r-1) to (a1-r-2) above. It is an acid dissociative group represented by . Wa ¹ is a hydrocarbon group with n _a2 +1 valence, n _a2 is 1 to 3, and Ra ² is an acid dissociable group represented by the above formula (a1-r-1) or (a1-r-3).]

The hydrocarbon group of Va ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group as the divalent hydrocarbon group in Va ¹ may be saturated or unsaturated, and is usually preferably saturated.

More specifically, the aliphatic hydrocarbon group includes linear or branched aliphatic hydrocarbon groups, aliphatic hydrocarbon groups containing a ring in the structure, and the like.

Additionally, Va ¹ may include a divalent hydrocarbon group bonded to an ether bond, a urethane bond, or an amide bond.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, further preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms.

The straight-chain aliphatic hydrocarbon group is preferably a straight-chain alkylene group, and specifically, a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) _2- ], and a trimethylene group [-(CH _2). ) ₃ -], tetramethylene group [-(CH ₂ ) ₄ -], pentamethylene group [-(CH ₂ ) ₅ -], etc.

The branched aliphatic hydrocarbon group is preferably a branched alkylene group, specifically -CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) ₂ -, -C. Alkylmethylene groups such as (CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, and -C(CH ₂ CH ₃ ) ₂ -; -CH(CH ₃ )CH ₂ -, -CH(CH ₃ )CH(CH ₃ )-, -C(CH ₃ ) ₂ CH ₂ -, -CH(CH ₂ CH ₃ )CH ₂ -, -C(CH Alkylethylene groups such as ₂ CH ₃ ) ₂ -CH ₂ - ; Alkyltrimethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ - and -CH ₂ CH(CH ₃ )CH ₂ -; Alkyl alkylene groups such as alkyl tetramethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -, etc. are mentioned. The alkyl group in the alkylakylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

The aliphatic hydrocarbon group containing a ring in the above structure includes an alicyclic hydrocarbon group (a group in which two hydrogen atoms are removed from the aliphatic hydrocarbon ring), and a group in which the alicyclic hydrocarbon group is bonded to the terminal of a straight-chain or branched aliphatic hydrocarbon group. , a group in which an alicyclic hydrocarbon group is interposed between a straight-chain or branched-chain aliphatic hydrocarbon group, and the like. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same ones as above.

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 polycyclic or monocyclic. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing two hydrogen atoms from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specifically adamantane, norbornane, and isocarbon group. Bornane, tricyclodecane, tetracyclododecane, etc. can be mentioned.

An aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring.

The aromatic hydrocarbon group as the divalent hydrocarbon group in Va ¹ preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, further preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and 6 ~10 is most preferable. However, the carbon number shall not include the carbon number in the substituent.

Specific examples of the aromatic ring possessed by the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; an aromatic heterocycle in which some of the carbon atoms constituting the aromatic hydrocarbon ring are replaced with heteroatoms; etc. can be mentioned. Hetero atoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms.

Specifically, the aromatic hydrocarbon group is a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring (arylene group); A group in which one hydrogen atom of the aromatic hydrocarbon ring (aryl group) is replaced with an alkylene group (e.g., benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group) , a group obtained by removing one hydrogen atom from an aryl group in an arylalkyl group such as a 1-naphthylethyl group or a 2-naphthylethyl group); etc. can be mentioned. 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 especially preferably 1.

In the above formula (a1-4), the n _a2 + 1 valent hydrocarbon group in Wa ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity, and may be saturated or unsaturated, and is usually preferably saturated. The aliphatic hydrocarbon group includes a straight-chain or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, or a combination of a straight-chain or branched aliphatic hydrocarbon group with a ring-containing aliphatic hydrocarbon group in the structure. One group can be mentioned, and specifically, the same group as Va ¹ of the above-mentioned formula (a1-3) can be mentioned.

The n _a2 +1 value is preferably 2 to 4, and more preferably 2 or 3.

(configuration unit (af))

In the present invention, the polymer compound (A1) contained in component (A) includes a structural unit (af) containing a fluorine atom in addition to the structural unit (a1). The resist composition of the present invention contains the structural unit (af), so that it contains CDU even if it contains a low content of the fluorine additive (component (F)) described later, which is added to impart water repellency to the resist film, or does not contain it at all. It is possible to obtain a resist pattern with excellent value and reduce the problem of resist film elution during liquid immersion exposure.

In general, the solubility of the fluorinated polymer compound used as the fluorine additive (F) in an organic developer is higher than the solubility of the polymer compound (A1) (where the acid dissociable group is not dissociated) in the unexposed portion of the resist film, Due to this difference in solubility during solvent development, the CDU value of a resist pattern obtained using a resist composition containing a fluorine additive (F) may be negatively affected.

In order to avoid this negative effect, if the fluorine additive (F) is not included in the resist composition or the content thereof is reduced, the water repellency of the resist film is reduced and substances in the resist film are eluted into the immersion solvent during liquid immersion exposure, leading to deterioration of the resist layer. etc. may result.

The resist composition according to the present invention contains a structural unit (af) containing a fluorine atom in the polymer compound (A1) contained in the base component (A), thereby resisting the fluorine additive (F), which negatively affects the CDU value. Even if the content in the composition is lowered or not included, it is possible to reduce material elution during liquid immersion exposure.

A preferred structural unit (af) according to the present invention contains one or more fluorine atoms, but does not contain a group represented by the following formula (af-x) in the structural unit.

[Formula 13]

(af-x)

In formula (af _- x), _R Can be substituted with O-, * refers to the binding position]

The structural unit (af) can preferably be represented by the following formula (af-1).

[Formula 14]

(af-1)

[In formula (af-1), R represents a hydrogen atom, an alkyl group, or a halogenated alkyl group; Y represents a single bond or a divalent linking group; X represents a hydrocarbon group containing a fluorine atom. However, -X, -Y- and -Y-X do not include the group represented by the formula (af-x) below.]

[Formula 15]

(af-x)

[In formula (af _- x), _R )Can be substituted with O-, and * refers to the binding position.]

In the formula (af-1), R is preferably a hydrogen atom, an alkyl group with 1 to 5 carbon atoms, or a halogenated alkyl group with 1 to 5 carbon atoms, and the halogenated alkyl group is preferably a fluorinated alkyl group. For ease of industrial availability, R is more preferably a hydrogen atom and an alkyl group with 1 to 5 carbon atoms, even more preferably an alkyl group with 1 to 5 carbon atoms, and particularly preferably a methyl group.

In the above formula (af-1), when Y is a divalent linking group, a linear or branched alkylene group, a divalent aromatic cyclic group, or a divalent linking group containing a hetero atom, or a fluorine atom in any of these It is desirable to contain it. Among these, a divalent linking group containing a hetero atom that may have a fluorine atom is particularly preferable.

Y When it is a linear or branched alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, especially preferably 1 to 4 carbon atoms, and preferably 1 to 4 carbon atoms. 3 is most preferable. Specifically, the same straight chain alkylene group and branched chain alkylene group as exemplified for Va' in the above formula (a1-3) can be mentioned.

Y When it is a divalent aromatic cyclic group, examples of the aromatic cyclic group include phenyl group, biphenyl group, fluorenyl group, naphthyl group, anthryl group, and phenanthryl group. A divalent aromatic hydrocarbon group obtained by removing one additional hydrogen atom from the nucleus of the aromatic hydrocarbon group of the monovalent aromatic hydrocarbon group;

An aromatic hydrocarbon group in which part of the carbon atoms constituting the ring of the divalent aromatic hydrocarbon group are replaced with heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms;

Arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, and 2-naphthylethyl group, and one additional hydrogen atom from the nucleus of the aromatic hydrocarbon. A removed aromatic hydrocarbon group, etc. can be mentioned.

Y When is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -C(=O)-, -OC(=O)-O- , -C(=O)-NH-, -NR ⁰⁴ - (R ⁰⁴ is a substituent such as an alkyl group, acyl group, etc.), -S-, -S(=O) ₂ -, -S(=O) ₂ - O-, a group represented by the formula -C(=O)-OR ⁰⁸ -, a group represented by the formula -OR ⁰⁸ -, a group represented by the formula -R ⁰⁹ -O-, a group represented by the formula -R ⁰⁹ -OR ⁰⁸ -, etc. can be mentioned.

R ⁰⁸ is a divalent hydrocarbon group that may have a substituent, and is preferably a straight-chain or branched aliphatic hydrocarbon group, and more preferably an alkylene group or an alkylalkylene group.

As the alkylene group, methylene group and ethylene group are particularly preferable.

The alkyl group in the alkylakylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably an ethyl group.

These R ⁰⁸ may contain a fluorine atom or may not contain a fluorine atom.

R ⁰⁹ is a divalent aromatic cyclic group, and is preferably a divalent aromatic hydrocarbon group in which one additional hydrogen atom has been removed from the nucleus of the aromatic hydrocarbon group of the monovalent aromatic hydrocarbon group, and a group in which one additional hydrogen atom has been removed from the naphthyl group is most preferred. desirable.

Any one or more -CH ₂ - constituting Y may be substituted with any of the groups represented by the following general formulas (II-1) to (II-4).

[Formula 16]

(II-1) (II-2) (II-3) (II-4)

Preferably, Y can be a divalent linking group represented by the following formula (af-1-y).

[Formula 17]

(af-1-y)

(af-1-y)

[In formula (af-1-y), Rf ¹⁰² and Rf ¹⁰³ each independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 5 carbon atoms, or a halogenated alkyl group with 1 to 5 carbon atoms, and Rf ¹⁰² and Rf ¹⁰³ are the same. It can be done or it can be different. nf ¹ is an integer from 0 to 5.]

Rf ¹⁰² and Rf ¹⁰³ are preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group is preferable.

In the formula (af-1-y), nf ¹ is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 0 or 1.

In formula (af-1), X is preferably a hydrocarbon group containing a fluorine atom.

The hydrocarbon group containing a fluorine atom may be linear, branched, or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and more preferably 1 to 10 carbon atoms. Particularly desirable.

In addition, as for the hydrocarbon group containing a fluorine atom, it is preferable that 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more are fluorinated, and especially, 60% or more are fluorinated. desirable. Among them, fluorinated hydrocarbon groups having 1 to 5 carbon atoms are more preferable, and are -CF ₃ , -CH ₂ -CF ₃ , -CH ₂ -CF ₂ -CF ₃ , -CH(CF ₃ ) ₂ , -CH ₂ -CH ₂ -CF ₃ , -CH ₂ -CH ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₃ are particularly preferred.

In the formula (af-x), _{R R} It may be monocyclic alkyl or polycyclic alkyl such as adamantyl group.

In addition, from the above formula (af-1), in addition to the group represented by the formula (af-x), a group containing an alcohol substituted with a plurality of fluorine atoms at the α or α’ position can be further excluded.

Preferred specific examples of the above formula (af-1) are as follows.

[Formula 18]

Equation (af-11)

Among the components of the polymer compound (A1), the proportion of the structural unit (af) is preferably 0.1 to 40 mol%, more preferably 0.5 to 25 mol%, relative to the total of all structural units constituting the resin component (A1). and 1 to 15 mol% is more preferable.

(Constitutive unit (a2))

In the present invention, the base component may contain a structural unit (a2) having a -SO ₂ --containing cyclic group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a heterocyclic group other than these.

When component (A) is used to form a resist film, the -SO ₂ --containing cyclic group, lactone-containing cyclic group, carbonate-containing cyclic group, or heterocyclic group other than these in the structural unit (a2) has an effect on the substrate of the resist film. It is effective in increasing adhesion.

In addition, when the structural unit (a1) has an -SO ₂ --containing cyclic group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a heterocyclic group other than these in its structure, the structural unit is structural unit (a2). However, this structural unit is assumed to correspond to structural unit (a1) and not to structural unit (a2).

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

[Formula 19]

[Wherein, R is a hydrogen atom, an alkyl group or a halogenated alkyl group, Ya ²¹ is a single bond or a divalent linking group, and La ²¹ is -O-, -COO-, -CON(R')-, -OCO-, - CONHCO- or -CONHCS-, and R' represents a hydrogen atom or a methyl group. However, when La ²¹ is -O-, Ya ²¹ does not become -CO-. Ra ²¹ is a -SO ₂ --containing cyclic group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a heterocyclic group other than these.]

In the above formula (a2-1), the alkyl group or halogenated alkyl group defined for R is preferably an alkyl group with 1 to 5 carbon atoms or a halogenated alkyl group with 1 to 5 carbon atoms.

In the above formula (a2-1), Ra ²¹ is preferably -SO ₂ --containing cyclic group, lactone-containing cyclic group, heterocyclic group, or carbonate-containing cyclic group.

“-SO ₂ --containing cyclic group” refers to a cyclic group containing a ring containing -SO ₂ - in its ring skeleton, and specifically, the sulfur atom (S) in -SO ₂ - is a cyclic group. It is a cyclic group that forms part of the ring skeleton. In the ring skeleton, the ring containing -SO ₂ - is counted as the first ring. If it is only that ring, it is called a monocyclic group, and if it also has another ring structure, it is called a polycyclic group regardless of the structure. The -SO ₂ --containing cyclic group may be monocyclic or polycyclic.

The -SO ₂ --containing cyclic group is, in particular, a cyclic group containing -O-SO ₂ - in its ring skeleton, that is, a sultone in which -OS- in -O-SO ₂ - forms a part of the ring skeleton. It is preferable that it is a cyclic group containing a ring. As the -SO ₂ --containing cyclic group, more specifically, groups each represented by the following formulas (a5-r-1) to (a5-r-4) can be mentioned.

[Formula 20]

[In the formula, Ra' ⁵¹ is each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group; R" is a hydrogen atom or an alkyl group; A" is an alkylene group of 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; * refers to the binding position.]

In the formulas (a5-r-1) to (a5-r-4), A" is the same as A" in the formulas (a2-r-1) to (a2-r-7) described later. The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group for Ra' ⁵¹ are of the formulas (a2-r-1) to (a2-) described later. It is the same as Ra' ²¹ in r-7).

Specific examples of groups each represented by formulas (a5-r-1) to (a5-r-4) are given below. “Ac” in the formula represents an acetyl group.

[Formula 21]

[In the formula, * refers to the binding position.]

In the present invention, when the structural unit (a2) contains an -SO ₂ --containing cyclic group, the logP value of the acrylic acid ester monomer containing an -SO ₂ --containing cyclic group is not particularly limited as long as it is less than 1.2, but among the above, The group represented by the above formula (a5-r-1) is preferred, and the above formulas (r-sl-1-1), (r-sl-1-18), (r-sl-3-1) and (r- It is more preferable to use at least one member selected from the group consisting of groups represented by any of sl-4-1), and the group represented by the above formula (r-sl-1-1) is most preferable.

“Lactone-containing cyclic group” refers to a cyclic group containing a ring (lactone ring) containing -O-C(=O)- in its ring skeleton. The lactone ring is counted as the first ring. If it is only a lactone ring, it is called a monocyclic group. If it has another ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.

There is no particular limitation on the lactone-containing cyclic group, and any group can be used. Specifically, groups represented by the following formulas (a2-r-1) to (a2-r-7) can be mentioned.

[Formula 22]

[In the formula, Ra' ²¹ is each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group; R" is a hydrogen atom or an alkyl group; A" is an alkylene group that may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, n' is an integer from 0 to 2, and m' is 0 or 1; * refers to the binding position.]

In the above formulas (a2-r-1) to (a2-r-7), A" is an alkylene group of 1 to 5 carbon atoms that may contain an oxygen atom (-O-) or a sulfur atom (-S-), It is an oxygen atom or a sulfur atom. The alkylene group having 1 to 5 carbon atoms in A" is preferably a linear or branched alkylene group, such as methylene group, ethylene group, n-propylene group, isopropylene group, etc. can be mentioned. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples include a group in which -O- or -S- is interposed between the ends of the alkylene group or carbon atoms, for example -O -CH ₂ -, -CH ₂ -O-CH ₂ -, -S-CH ₂ -, -CH ₂ -S-CH ₂ -, 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. Ra' ²¹ is each independently an alkyl group, an alkoxy group, It is a halogen atom, a halogenated alkyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group.

The alkyl group for Ra' ²¹ is preferably an alkyl group having 1 to 5 carbon atoms.

The alkoxy group for Ra' ²¹ is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, a group in which an oxygen atom (-O-) is linked to the alkyl group exemplified as the alkyl group for Ra' ²¹ above can be mentioned.

The halogen atom in Ra' ²¹ includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and a fluorine atom is preferable.

Examples of the halogenated alkyl group for Ra' ²¹ include groups in which some or all of the hydrogen atoms of the alkyl group for Ra' ²¹ are replaced with the halogen atoms. As the halogenated alkyl group, a fluoroalkyl group is preferable, and a perfluoroalkyl group is particularly preferable.

Specific examples of groups each represented by formulas (a2-r-1) to (a2-r-7) are given below.

[Formula 23]

[In the formula, * refers to the binding position.]

In the present invention, the structural unit (a2) is preferably a group represented by the above formula (a2-r-1) or (a2-r-2), respectively, and the structural unit (a2) is preferably a group represented by the above formula (r-lc-1-1) or (r The groups each represented by -lc-2-7) are more preferable.

“Carbonate-containing cyclic group” refers to a cyclic group containing a ring (carbonate ring) containing -O-C(=O)-O- in its ring skeleton. The carbonate ring is counted as the first ring. If it is only a carbonate ring, it is called a monocyclic group. If it has another ring structure, it is called a polycyclic group regardless of the structure. The carbonate-containing cyclic group may be a monocyclic group or a polycyclic group.

Specifically, groups represented by the following formulas (ax3-r-1) to (ax3-r-3) can be mentioned.

[Formula 24]

[In the ^formula , Ra' is a hydrogen atom or an alkyl group; A" is an alkylene group of 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom; q' is 0 or 1; * refers to the binding position.]

Specific examples of A" in the above formulas (ax3-r-1) to (ax3-r-3) are the same as A" in the above formulas (a2-r-1) to (a2-r-7). The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group for Ra' ^x31 are each of the above formulas (a2-r-1) to (a2- The same examples as those exemplified in the description of Ra' ²¹ in r-7) can be given.

Specific examples of groups represented by formulas (ax3-r-1) to (ax3-r-3) are given below.

[Formula 25]

[In the formula, * refers to the binding position.]

“Heterocyclic group” refers to a cyclic group containing one or more atoms other than carbon in addition to carbon, and includes heterocyclic groups exemplified by (r-hr-1) to (r-hr-16) below, respectively. , nitrogen-containing heterocycles, etc. Examples of the nitrogen-containing heterocyclic group include cycloalkyl groups having 3 to 8 carbon atoms which may be substituted with one or two oxo groups. Preferred examples of the cycloalkyl group include 2,5-dioxopyrrolidine and 2,6-dioxopiperidine.

[Formula 26]

[In the formula, * refers to the binding position.]

The structural unit (a2) preferably has a lactone-containing cyclic group, and more preferably has a lactone-containing cyclic group each represented by the above formulas (a2-r-1) to (a2-r-7).

Specific examples of the structural unit (a2) having a lactone-containing cyclic group are given below. In each formula below, R ^α is a hydrogen atom, a methyl group, or a trifluoromethyl group.

[Formula 27]

When the polymer compound (A1) component has a structural unit (a2), the number of structural units (a2) that the polymer compound (A1) component has may be one or two or more types.

The proportion of the structural unit (a2) is preferably 1 to 60 mol%, more preferably 5 to 50 mol%, relative to the total of all structural units constituting the component (A).

By setting the ratio of the structural unit (a2) to the lower limit or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by setting it to the upper limit or lower, it is possible to achieve balance with other structural units, and various lithography characteristics and pattern shapes can be achieved. It gets better.

(Constitutive unit (a3))

The structural unit (a3) is a structural unit containing a polar group-containing aliphatic hydrocarbon group (however, those corresponding to the structural units (a1) and (a2) described above are excluded).

It is thought that when the polymer compound (A1) component has the structural unit (a3), the hydrophilicity of the polymer compound (A) component increases and contributes to the improvement of resolution.

The polar group includes a hydroxyl group, a cyano group, a carboxyl group, and a hydroxyalkyl group in which part of the hydrogen atoms of the alkyl group are replaced with fluorine atoms, and a hydroxyl group is particularly preferable.

Examples of the aliphatic hydrocarbon group include linear or branched hydrocarbon groups having 1 to 10 carbon atoms (preferably alkylene groups) and cyclic aliphatic hydrocarbon groups (cyclic groups). The cyclic group may be a monocyclic group or a polycyclic group. For example, in a resin for a resist composition for an ArF excimer laser, it can be appropriately selected and used from among many proposed groups. The cyclic group is preferably a polycyclic group, and more preferably has 7 to 30 carbon atoms.

Among them, structural units derived from an acrylic acid ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a portion of the hydrogen atoms of the hydroxyl group, cyano group, carboxyl group, or alkyl group are substituted with fluorine atoms are more preferable. Examples of the polycyclic group include groups obtained by removing two or more hydrogen atoms from bicycloalkanes, tricycloalkanes, tetracycloalkanes, etc. Specifically, groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane can be mentioned. Among these polycyclic groups, groups obtained by removing two or more hydrogen atoms from adamantane, groups obtained by removing two or more hydrogen atoms from norbornane, and groups obtained by removing two or more hydrogen atoms from tetracyclododecane are industrially preferable.

The structural unit (a3) is not particularly limited and any unit can be used as long as it contains an aliphatic hydrocarbon group containing a polar group.

The structural unit (a3) is preferably a structural unit derived from an acrylic acid ester in which the hydrogen atom bonded to the carbon atom at the α position may be substituted with a substituent and containing a polar group-containing aliphatic hydrocarbon group.

As the structural unit (a3), when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a structural unit derived from hydroxyethyl ester of acrylic acid is preferable, When the hydrocarbon group is a polycyclic group, structural units represented by the following formulas (a3-1) to (a3-5) are preferable, and structural units represented by the following formula (a3-1) are more preferable.

[Formula 28]

[Wherein, R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t' is an integer of 1 to 3, l is an integer of 1 to 5, and s is It is an integer from 1 to 3.]

In formula (a3-1), j is preferably 1 or 2, and is more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3rd position of the adamantyl group.

j is preferably 1, and in particular, it is preferable that the hydroxyl group is bonded to the 3rd position of the adamantyl group.

In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.

In formula (a3-3), t' is preferably 1. l is preferably 1. s is preferably 1. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxyl group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5 or 6 position of the norbornyl group.

The number of structural units (a3) contained in the polymer compound (A1) component may be one, or two or more types may be used.

The proportion of the structural unit (a3) in the polymer compound (A1) component is preferably 5 to 40 mol%, more preferably 5 to 30 mol%, relative to the total of all structural units constituting the resin component (A1). and 5 to 25 mol% is more preferable.

By setting the ratio of the structural unit (a3) to the lower limit or more, the effect of containing the structural unit (a3) is sufficiently obtained, and by setting it to the upper limit or less, it becomes easy to maintain a balance with other structural units.

The polymer compound (A1) component may have the following structural unit (a4) in addition to the structural units (a1), (a2), and (a3).

(Constitutive unit (a4))

The structural unit (a4) is a structural unit containing an acid non-dissociable cyclic group. When the high molecular compound (A1) component has the structural unit (a4), the dry etching resistance of the formed resist pattern is improved. Additionally, the hydrophobicity of the polymer compound (A1) component increases. It is believed that improvement in hydrophobicity contributes to improvement in resolution, resist pattern shape, etc., especially in the case of organic solvent development.

The “acid non-dissociable cyclic group” in the structural unit (a4) is a cyclic group that remains in the structural unit without being dissociated even when the acid acts on it when an acid is generated from the component (B), which will be described later, by exposure to light.

The structural unit (a4) is preferably, for example, a structural unit derived from an acrylic acid ester containing an acid-non-dissociable aliphatic cyclic group. The cyclic group may, for example, be the same as that exemplified in the case of the structural unit (a1) described above, and may be used in resists such as those for ArF excimer lasers and KrF excimer lasers (preferably for ArF excimer lasers). A number of those conventionally known for use in the resin component of the composition can be used.

In particular, at least one type selected from tricyclodecyl group, adamantyl group, tetracyclododecyl group, isobornyl group, and norbornyl group is preferable because it is easy to obtain industrially. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

Specific examples of the structural unit (a4) include those having structures of the following formulas (a4-1) to (a4-7).

[Formula 29]

[Wherein, R ^α represents a hydrogen atom, a methyl group, or a trifluoromethyl group]

The number of structural units (a4) contained in the polymer compound (A1) component may be one or two or more types.

When the structural unit (a4) is contained in the polymer compound (A1) component, the proportion of the structural unit (a4) is preferably 1 to 30 mol% with respect to the total of all structural units constituting the (A1) component, and is preferably 10 It is more preferable that it is ~20 mol%.

The polymer compound (A1) component preferably has structural units (a1) and (a2) or is a copolymer having structural units (a1), (a2), and (a3).

The polymer compound (A1) component can be obtained by polymerizing the monomers from which each structural unit is derived, for example, by known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate. You can.

In addition, during the polymerization, the polymer compound (A1) component is used in combination with a chain transfer agent such as HS-CH ₂ -CH ₂ -CH ₂ -C(CF ₃ ) ₂ -OH, thereby adding - to the terminal. A C(CF ₃ ) ₂ -OH group may be introduced. In this way, a copolymer into which a hydroxyalkyl group is introduced, in which some of the hydrogen atoms of the alkyl group are replaced with fluorine atoms, is effective in reducing development defects and reducing LER (line edge roughness: uneven unevenness of the line side wall).

In the present invention, the mass average molecular weight (Mw) (based on polystyrene conversion by gel permeation chromatography) of the polymer compound (A1) component is not particularly limited, and is preferably 1,000 to 50,000, and more preferably 1,500 to 30,000. 2,000 to 20,000 is more preferable, and 5,000 to 16,000 is most preferable. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent for use as a resist, and if it is above the lower limit of this range, the dry etching resistance and cross-sectional shape of the resist pattern are good.

The polymer compound (A1) component may be used individually by one type, or may be used in combination of two or more types.

The ratio of the polymer compound (A1) component in the base component (A) is preferably 25% by mass or more, more preferably 50% by mass, still more preferably 75% by mass, and 100% by mass relative to the total mass of the base component (A). It may be mass%. When the ratio is 25% by mass or more, lithography characteristics are further improved.

In this invention, component (A) may be used individually by 1 type, or may be used in combination of 2 or more types.

In the present invention, the content of component (A) may be adjusted according to the resist film thickness to be formed, etc.

<Acid generator component; (B) Ingredient>

In addition to component (A), the resist composition of the present invention further contains an acid generator component (hereinafter referred to as “component (B)”).

The component (B) is not particularly limited, and those proposed so far as acid generators for chemically amplified resists can be used.

Such acid generators include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators; bisalkyl or bisarylsulfonyldiazomethanes, and poly(bissulfonyl)diazomethane. Diazomethane-based acid generators such as those listed above; various types such as nitrobenzylsulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators can be mentioned. Among them, it is preferable to use an onium salt-based acid generator.

Examples of onium salt-based acid generators include compounds represented by the following formula (b-1) (hereinafter also referred to as “component (b-1)”) and compounds represented by formula (b-2) (hereinafter referred to as “component (b-1)”) (b-2) component”) or a compound represented by formula (b-3) (hereinafter also referred to as “(b-3) component”).

[Formula 30]

[In the formula, R ¹⁰¹ , R ¹⁰⁴ to R ¹⁰⁸ each independently represents 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. R ¹⁰⁴ and R ¹⁰⁵ may be bonded to each other to form a ring. R ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. Y ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom. V ¹⁰¹ to V ¹⁰³ are each independently a single bond, an alkylene group, or a fluorinated alkylene group. L ¹⁰¹ to L ¹⁰² are each independently a single bond or an oxygen atom. L ¹⁰³ to L ¹⁰⁵ are each independently a single bond, -CO- or -SO ₂ -. m is an integer greater than 1, and M' ^m+ is an m-valent onium cation.]

{anion part}

· Anionic part of component (b-1)

In formula (b-1), R ¹⁰¹ is 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.

Cyclic group that 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. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. Moreover, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

The aromatic hydrocarbon group for R ¹⁰¹ is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. However, the carbon number shall not include the carbon number in the substituent.

The aromatic ring possessed by the aromatic hydrocarbon group for R ¹⁰¹ specifically includes benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, or an aromatic complex in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. A ring, etc. may be mentioned. Hetero atoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms.

The aromatic hydrocarbon group for R ¹⁰¹ specifically includes a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: e.g., phenyl group, naphthyl group, etc.), and one hydrogen atom in the aromatic ring is alkylene. and groups substituted with groups (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). 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 especially preferably 1.

The cyclic aliphatic hydrocarbon group for R ¹⁰¹ includes an aliphatic hydrocarbon group containing a ring in the structure.

In this structure, the aliphatic hydrocarbon group containing a ring includes an alicyclic hydrocarbon group (a group in which one hydrogen atom has been removed from the aliphatic hydrocarbon ring), and a group in which the alicyclic hydrocarbon group is bonded to the terminal of a linear or branched aliphatic hydrocarbon group. , a group in which an alicyclic hydrocarbon group is interposed between a straight-chain or branched-chain aliphatic hydrocarbon group, and the like.

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. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing one or more hydrogen atoms from a monocycloalkane is preferable. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among them, the polycycloalkanes include polycycloalkanes having a polycyclic skeleton of a bridged ring system such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane; rings having a steroid skeleton; A polycycloalkane having a polycyclic skeleton of a condensed ring system such as a polycycloalkane is more preferable.

Among them, the cyclic aliphatic hydrocarbon group for R ¹⁰¹ is preferably a group obtained by removing one or more hydrogen atoms from a monocycloalkane or polycycloalkane, and more preferably a group obtained by removing one hydrogen atom from a polycycloalkane, Adamantyl group and norbornyl group are particularly preferred, and adamantyl group is most preferred.

The linear or branched aliphatic hydrocarbon group that may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Most desirable.

As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], and a trimethylene group [-( CH ₂ ) ₃ -], tetramethylene group [-(CH ₂ ) ₄ -], pentamethylene group [-(CH ₂ ) ₅ -], etc.

The branched aliphatic hydrocarbon group is preferably a branched alkylene group, specifically -CH( _CH3 )-, -CH( _{CH2CH3 )} -, -C( _CH3 ) _2- , Alkylmethylene groups such as -C(CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, -C(CH ₂ CH ₃ ) _2- ; -CH(CH ₃ )CH ₂ -, -CH(CH ₃ )CH(CH ₃ )-, -C(CH ₃ ) ₂ CH ₂ -, -CH(CH ₂ CH ₃ )CH ₂ -, -C(CH ₂ CH ₃ ) Alkyl ethylene groups such as ₂ -CH ₂ -; Alkyl trimethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ -; -CH(CH ₃ )CH ₂ CH Alkyl alkylene groups such as alkyl tetramethylene groups such as _{2CH 2} -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -, etc. are mentioned. The alkyl group in the alkylakylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

Additionally, the cyclic hydrocarbon group for R ¹⁰¹ may contain a hetero atom such as a heterocyclic ring. Specifically, lactone-containing cyclic groups each represented by the above formulas (a2-r-1) to (a2-r-7), and - each represented by the above formulas (a5-r-1) to (a5-r-2). SO ₂ -containing polycyclic groups and other heterocyclic groups represented by the following formulas (r-hr-1) to (r-hr-16), respectively.

[Formula 31]

[In the formula, * refers to the binding position.]

Examples of the substituent in the cyclic group of R ¹⁰¹ include an alkyl group, an alkoxy group, a halogen atom, alkyl halogenation, 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 most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

As the alkoxy group as a substituent, an alkoxy group having 1 to 5 carbon atoms is preferable, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, and tert-butoxy group are more preferable, and methoxy group is more preferable. , ethoxy group is most preferred.

Halogen atoms as substituents include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms being preferred.

Examples of the halogenated alkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups in which some or all of the hydrogen atoms are substituted with the halogen atoms described above. there is.

A carbonyl group as a substituent is a group that substitutes a methylene group (-CH ₂ -) constituting a cyclic hydrocarbon group.

Chain alkyl group that may have a substituent:

The chain alkyl group for R ¹⁰¹ may be either linear or branched.

The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, tridecyl group, and isotridecyl group. , tetradecyl group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henicosyl group, docosyl group, etc.

The branched chain alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2 -Ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, etc. are mentioned.

Chain alkenyl group that may have a substituent:

The chain alkenyl group for R ¹⁰¹ may be linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, and even more preferably 2 to 4 carbon atoms. 3 is particularly preferable. Examples of straight-chain alkenyl groups include vinyl group, propenyl group (allyl group), and butynyl group. Examples of branched chain alkenyl groups include 1-methylvinyl group, 2-methylvinyl group, 1-methylpropenyl group, and 2-methylpropenyl group.

As for the chain alkenyl group, among the above, a straight chain alkenyl group is preferable, a vinyl group and a propenyl group are more preferable, and a vinyl group is particularly preferable.

Substituents for the chain alkyl or alkenyl group of R ¹⁰¹ include, for example, an alkoxy group, halogen atom, halogenated alkyl group, hydroxyl group, carbonyl group, nitro group, amino group, and the cyclic group for R ¹⁰¹ . You can.

Among them, R ¹⁰¹ is preferably a cyclic group that may have a substituent or a chain alkyl group that may have a substituent, more preferably a cyclic group that may have a substituent, and a cyclic hydrocarbon group that may have a substituent. It is more desirable.

Among them, a phenyl group, a naphthyl group, a group obtained by removing one or more hydrogen atoms from a polycycloalkane, a lactone-containing cyclic group each represented by the above formulas (a2-r-1) to (a2-r-7), and the above formula (a5) -SO ₂ --containing polycyclic groups each represented by -r-1) to (a5-r-2) are preferred, and among these, groups obtained by removing one or more hydrogen atoms from polycycloalkane, the formula (a5-r-) 1) -SO ₂ --containing polycyclic groups each represented by to (a5-r-2) are more preferable.

In formula (b-1), Y ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom.

When Y ¹⁰¹ is a divalent linking group containing an oxygen atom, Y ¹⁰¹ may contain an atom other than an oxygen atom. Atoms other than oxygen atoms include, for example, carbon atoms, hydrogen atoms, sulfur atoms, and nitrogen atoms.

Examples of the divalent linking group containing an oxygen atom include oxygen atom (ether bond: -O-), ester bond (-C(=O)-O-), and oxycarbonyl group (-OC(=O)- ), amide bond (-C(=O)-NH-), carbonyl group (-C(=O)-), carbonate bond (-OC(=O)-O-), non-hydrocarbon oxygen atom-containing linking group ；A combination of a non-hydrocarbon oxygen atom-containing linking group and an alkylene group may be included. A sulfonyl group (-SO ₂ -) may be further connected to this combination. Examples of the divalent linking group containing such an oxygen atom include linking groups each represented by the following formulas (y-al-1) to (y-al-7).

[Formula 32]

[Wherein, ^V'101 is a single bond or an alkylene group having 1 to 5 carbon atoms, and ^V'102 is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.]

The divalent saturated hydrocarbon group at ^V'102 is preferably an alkylene group with 1 to 30 carbon atoms, more preferably an alkylene group with 1 to 10 carbon atoms, and even more preferably an alkylene group with 1 to 5 carbon atoms.

The alkylene group for ^V'101 and ^V'102 may be a straight-chain alkylene group or a branched-chain alkylene group, and a straight-chain alkylene group is preferable.

As the alkylene group in V' ¹⁰¹ and V' ¹⁰² , specifically, methylene group [-CH ₂ -];-CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, -C(CH ₂ CH ₃ ) _2- , etc. Alkylmethylene groups; Ethylene group [-CH ₂ CH ₂ -]；-CH(CH ₃ )CH ₂ -, -CH(CH ₃ )CH(CH ₃ )-, -C(CH ₃ ) ₂ CH ₂ -, -CH(CH ₂ CH ₃ )CH ₂ - Alkylethylene group; Trimethylene group (n-propylene group) [-CH ₂ CH ₂ CH ₂ -]; -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ ) Alkyltrimethylene group such as CH ₂ -; Tetramethylene group [-CH ₂ CH ₂ CH ₂ CH ₂ -]; -CH(CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ ) Alkyl tetramethylene groups such as CH ₂ CH ₂ -; pentamethylene groups [-CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -] and the like.

Additionally, some methylene groups in the alkylene group at V' ¹⁰¹ or V' ¹⁰² may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms.

As Y ¹⁰¹ , a divalent linking group containing an ester bond or a divalent linking group containing an ether bond is preferable, and linking groups each represented by the above formulas (y-al-1) to (y-al-5) are more preferable. And, linking groups each represented by the above formulas (y-al-1) to (y-al-3) are more preferable.

In formula (b-1), V ¹⁰¹ is a single bond, an alkylene group, or a fluorinated alkylene group. The alkylene group and fluorinated alkylene group for V ¹⁰¹ preferably have 1 to 4 carbon atoms. Examples of the fluorinated alkylene group for V ¹⁰¹ include groups in which some or all of the hydrogen atoms of the alkylene group for V ¹⁰¹ are substituted with fluorine atoms. Among these, V ¹⁰¹ is preferably a single bond or a fluorinated alkylene group having 1 to 4 carbon atoms.

In formula (b-1), R ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. R ¹⁰² is preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and more preferably a fluorine atom.

Specific examples of the anionic portion of component (b-1) include, for example, when Y ¹⁰¹ is a single bond, fluorinated alkyl sulphos such as trifluoromethane sulfonate anion and perfluorobutane sulfonate anion. Examples include nate anions; when Y ¹⁰¹ is a divalent linking group containing an oxygen atom, examples include anions represented by any of the following formulas (an-1) to (an-3).

[Formula 33]

[In the formula, R$ ¹⁰¹ is an aliphatic cyclic group that may have a substituent, a group each represented by the above formulas (r-hr-1) to (r-hr-6), or a chain alkyl group that may have a substituent. and; R$ ¹⁰² is an aliphatic cyclic group which may have a substituent, a lactone-containing cyclic group each represented by the above formulas (a2-r-1) to (a2-r-7), or the above formula (a5-r-1) ) are -SO ₂ --containing polycyclic groups each represented by to (a5-r-2); R" ¹⁰³ is an aromatic cyclic group that may have a substituent, an aliphatic cyclic group that may have a substituent, or a substituent. is a chain-like alkenyl group; v" is each independently an integer from 0 to 3, q" is each independently an integer from 1 to 20, t" is an integer from 1 to 3, and n" is 0 or 1. am.]

The aliphatic cyclic group that may have a substituent for R$ ¹⁰¹ , R$ ¹⁰² and R$ ¹⁰³ is preferably a group exemplified as the cyclic aliphatic hydrocarbon group for R ¹⁰¹ above. Examples of the substituent include the same substituents that may substitute the cyclic aliphatic hydrocarbon group for R ¹⁰¹ .

The aromatic cyclic group that may have a substituent for R$ ¹⁰³ is preferably a group exemplified as the aromatic hydrocarbon group for the cyclic hydrocarbon group for R ¹⁰¹ above. Examples of the substituent include the same substituents that may substitute the aromatic hydrocarbon group for R ¹⁰¹ .

The chain alkyl group that may have a substituent for R$ ¹⁰¹ is preferably a group exemplified as the chain alkyl group for R ¹⁰¹ above. The chain alkenyl group that may have a substituent at R$ ¹⁰³ is preferably a group exemplified as the chain alkenyl group at R ¹⁰¹ above.

· Anionic part of (b-2) component

In formula (b-2), R ¹⁰⁴ and R ¹⁰⁵ each independently represent 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, Each of them may be the same as R ¹⁰¹ in the above formula (b-1). However, R ¹⁰⁴ and R ¹⁰⁵ may be bonded to each other to form a ring.

R ¹⁰⁴ and R ¹⁰⁵ are preferably a linear alkyl group that may have a substituent, and more preferably a linear or branched alkyl group or a linear or branched fluorinated alkyl 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. The smaller the carbon number of the chain alkyl group of R ¹⁰⁴ and R ¹⁰⁵ within the above-mentioned carbon number range, the more preferable it is for reasons such as good solubility in the resist solvent. In addition, in the chain alkyl group of R ¹⁰⁴ and R ¹⁰⁵ , the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength, and the improved transparency to high-energy light or electron beams of 200 nm or less. Therefore, it is desirable.

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 replaced with fluorine atoms. am.

In formula (b-2), V ¹⁰² and V ¹⁰³ each independently represent a single bond, an alkylene group, or a fluorinated alkylene group, and each may be the same as V ¹⁰¹ in formula (b-1).

In formula (b-2), L ¹⁰¹ and L ¹⁰² are each independently a single bond or an oxygen atom.

· Anionic part of component (b-3)

In formula (b-3), R ¹⁰⁶ to R ¹⁰⁸ each independently represent a cyclic group that may have a substituent, a chain alkyl group that may have a substituent, or a chain alkenyl group that may have a substituent, Each of them may be the same as R ¹⁰¹ in the above formula (b-1).

L ¹⁰³ to L ¹⁰⁵ are each independently a single bond, -CO- or -SO ₂ -.

{cation part}

In formulas (b-1), (b-2) and (b-3), m is an integer of 1 or more, ^M'm+ is an m-valent onium cation, and a sulfonium cation or an iodonium cation is suitably used. and organic cations each represented by the following formulas (ca-1) to (ca-4) are particularly preferable.

[Formula 34]

[In the formula, R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² each independently represent an aryl group, an alkyl group, or an alkenyl group which may have a substituent, and R ²⁰¹ to R ²⁰³ , R ²⁰⁶ to R ²⁰⁷ , and R ²¹¹ to R ²¹² may be bonded to each other to form a ring with the sulfur atom in the formula. R ²⁰⁸ to R ²⁰⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ²¹⁰ represents an aryl group that may have a substituent, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, or a substituent. It is an -SO ₂ --containing cyclic group that may be present, L ²⁰¹ represents -C(=O)- or -C(=O)-O-, and Y ²⁰¹ each independently represents an arylene group, an alkylene group, or an alkene group. It represents a nylene group, x is 1 or 2, and W ²⁰¹ represents a (x+1) valent linking group.]

The aryl group for R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group and a naphthyl group are preferable.

The alkyl group for R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.

The alkenyl group for R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² preferably has 2 to 10 carbon atoms.

Substituents that R ²⁰¹ to R ²⁰⁷ and R ²¹⁰ to R ²¹² may have include, for example, an alkyl group, halogen atom, halogenated alkyl group, carbonyl group, cyano group, amino group, aryl group, and the following formula (ca-r-1) Groups each represented by ~ (ca-r-7) can be mentioned.

[Formula 35]

[In the formula, R' ²⁰¹ each independently represents a hydrogen atom, a cyclic group that may have a substituent, a chain alkyl group that may have a substituent, or a chain alkenyl group that may have a substituent.]

The cyclic group that may have a substituent for R' ²⁰¹ , the chain alkyl group that may have a substituent, or the chain alkenyl group that may have a substituent include the same as R ¹⁰¹ in the above-mentioned formula (b-1). You can. In addition, the cyclic group that may have a substituent at R' ²⁰¹ or the chain alkyl group that may have a substituent include the same acid dissociable group in the structural unit (a1) described above.

When R ²⁰¹ to R ²⁰³ , R ²⁰⁶ to R ²⁰⁷ , and R ²¹¹ to R ²¹² combine with each other to form a ring with the sulfur atom in the formula, they are heteroatoms such as a sulfur atom, an oxygen atom, or a nitrogen atom, a carbonyl group, Bonded through a functional group such as -SO-, -SO ₂ -, -SO ₃ -, -COO-, -CONH- or -N(R _N )- (where R _N is an alkyl group having 1 to 5 carbon atoms) You can do it. As for the ring formed, one ring containing the sulfur atom of the formula in its ring skeleton is preferably a 3- to 10-membered ring including the sulfur atom, and is particularly preferably a 5- to 7-membered ring. Specific examples of the ring formed include, for example, a thiophene ring, a thiazole ring, a benzothiophene ring, a thiantrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, and a thioxanthone. rings, thianthrene rings, phenoxathiin rings, tetrahydrothiophenium rings, tetrahydrothiopyranium rings, etc.

R ²⁰⁸ to R ²⁰⁹ each independently represent a hydrogen atom or an alkyl group with 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group with 1 to 3 carbon atoms, and when they are an alkyl group, they may combine with each other to form a ring.

R ²¹⁰ is 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 an -SO ₂ --containing cyclic group which may have a substituent.

The aryl group for R ²¹⁰ includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group and a naphthyl group are preferable.

The alkyl group for R ²¹⁰ is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.

The alkenyl group for R ²¹⁰ preferably has 2 to 10 carbon atoms.

As the -SO ₂ - containing cyclic group for R ²¹⁰ which may have a substituent, the above-mentioned “-SO ₂ - containing polycyclic group” is preferable, and the group represented by the formula (a5-r-1) is more preferable. do.

Y ²⁰¹ each independently represents an arylene group, an alkylene group, or an alkenylene group.

The arylene group for Y ²⁰¹ includes a group obtained by removing one hydrogen atom from the aryl group exemplified as the aromatic hydrocarbon group for R ¹⁰¹ in the above-mentioned formula (b-1).

The alkylene group and alkenylene group for Y ²⁰¹ include groups obtained by removing one hydrogen atom from the groups exemplified as the chain alkyl group and chain alkenyl group for R ¹⁰¹ in the above-mentioned formula (b-1). there is.

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

W ²⁰¹ is a (x+1) valent, that is, a divalent or trivalent linking group.

The divalent linking group in W ²⁰¹ is preferably a divalent hydrocarbon group that may have a substituent, and is the same as Va ⁰¹ in La ⁰¹¹ in the formula (a01-1) described above, and a divalent hydrocarbon group that may have a substituent. A hydrocarbon group can be exemplified. The divalent linking group in W ²⁰¹ may be linear, branched, or cyclic, and is preferably cyclic. Among them, a group in which two carbonyl groups are combined at both ends of an arylene group is preferable. Examples of the arylene group include phenylene group and naphthylene group, and phenylene group is particularly preferable.

Examples of the trivalent linking group in W ²⁰¹ include a group in which one hydrogen atom is removed from the divalent linking group in W ²⁰¹ , a group in which the divalent linking group is further bonded to the divalent linking group, and the like. The trivalent linking group for W ²⁰¹ is preferably a group in which two carbonyl groups are bonded to an arylene group.

Specifically, suitable cations represented by the above formula (ca-1) include cations each represented by the following formulas (ca-1-1) to (ca-1-67).

[Formula 36]

[Formula 37]

[Formula 38]

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

[Formula 39]

[In the formula, R$ ²⁰¹ is a hydrogen atom or a substituent, and the substituents are the same as those exemplified as the substituents that R ²⁰¹ to R ²⁰⁷ and R ²¹⁰ to R ²¹² may have above.]

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

Suitable cations represented by the above formula (ca-3) specifically include cations each represented by the following formulas (ca-3-1) to (ca-3-6).

[Formula 40]

Specific examples of suitable cations represented by the formula (ca-4) include cations represented by the following formulas (ca-4-1) to (ca-4-2), respectively.

[Formula 41]

Among the above, the cation moiety [(M' ^m+ ) _1/m ] is preferably a cation represented by the formula (ca-1), and is represented by the formulas (ca-1-1) to (ca-1-67), respectively. Cations are more preferred.

(B) Component may use the above-mentioned acid generator individually by 1 type, or may use it in combination of 2 or more types.

When the resist composition contains component (B), the content of component (B) is preferably 0.5 to 60 parts by mass, more preferably 1 to 50 parts by mass, and 1 to 40 parts by mass relative to 100 parts by mass of component (A). wealth is more desirable.

By setting the content of component (B) within the above range, pattern formation can be sufficiently performed. Additionally, when each component of the resist composition is dissolved in an organic solvent, a uniform solution is easily obtained and the storage stability of the resist composition is improved, which is preferred.

<Other ingredients>

In addition to the above-described components (A) and (B), the resist composition of the present invention may further contain components other than the above components. Other components include, for example, the (D) component, (E) component, (F) component, and (S) component shown below.

[(D) Ingredient: Acid diffusion control agent component]

The resist composition of the present invention contains, in addition to component (A), or in addition to component (A) and component (B), an acid diffusion control agent component (hereinafter referred to as “component (D)”). You can do it. The component (D) acts as a quencher (acid diffusion control agent) that traps acids generated during exposure in the resist composition.

The component (D) may be a photodegradable base (D1) (hereinafter referred to as “component (D1)”) that decomposes upon exposure and loses acid diffusion control, as long as it does not fall under the component (D1). A nitrogen organic compound (D2) (hereinafter referred to as “(D2) component”) may be used.

· (D1) About the ingredient

By using a resist composition containing the component (D1), the contrast between exposed and unexposed areas can be improved when forming a resist pattern.

The (D1) component is not particularly limited as long as it decomposes upon exposure and loses acid diffusion control, and includes a compound represented by the following formula (d1-1) (hereinafter referred to as “(d1-1) component”), A compound represented by the following formula (d1-2) (hereinafter referred to as “(d1-2) component”) and a compound represented by the following formula (d1-3) (hereinafter referred to as “(d1-3) component”. ) One or more compounds selected from the group consisting of is preferable.

Components (d1-1) to (d1-3) do not act as a quencher in the exposed portion of the resist film because they decompose and lose acid diffusion control (basicity), but act as a quencher in the unexposed portion.

[Formula 42]

[In the formula, Rd ¹ to Rd ⁴ are 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. However, it is assumed that the fluorine atom is not bonded to the carbon atom adjacent to the S atom in Rd ² in the formula (d1-2). Yd ¹ is a single bond or a divalent linking group. m is an integer of 1 or more, and M ^m+ is each independently an m-valent organic cation.]

{(d1-1) component}

·· Anion part

In formula (d1-1), Rd ¹ is a cyclic group that may have a substituent, a chain alkyl group that may have a substituent, or a chain alkenyl group that may have a substituent, respectively, in the formula (b-1) ), the same as R ¹⁰¹ in ).

Among these, Rd ¹ is preferably an aromatic hydrocarbon group that may have a substituent, an aliphatic cyclic group that may have a substituent, or a chain alkyl group that may have a substituent. Substituents that these groups may have include hydroxyl group, oxo group, alkyl group, aryl group, fluorine atom, fluoroalkyl group, lactone-containing cyclic group each represented by the above formulas (a2-r-1) to (a2-r-6), An ether bond, an ester bond, or a combination thereof may be mentioned. When an ether bond or an ester bond is included as a substituent, an alkylene group may be present.

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

The aliphatic cyclic group is more preferably a group obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

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

The chain alkyl group may have a fluorine atom or a fluorinated alkyl group as a substituent, and the number of carbon atoms of the fluorinated alkyl group is preferably 1 to 11, more preferably 1 to 8, and still more preferably 1 to 4. The fluorinated alkyl group may contain atoms other than fluorine atoms. Atoms other than fluorine atoms include, for example, oxygen atoms, sulfur atoms, and nitrogen atoms.

Rd ¹ is preferably a fluorinated alkyl group in which some or all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms, and a fluorinated alkyl group in which all the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms ( A straight-chain perfluoroalkyl group) is particularly preferable.

Below, preferred specific examples of the anion portion of component (d1-1) are shown.

[Formula 43]

·· Cation part

In formula (d1-1), M ^m+ is an m-valent organic cation.

Suitable organic cations for M ^m+ include those similar to the cations each represented by the above formulas (ca-1) to (ca-4), and the cation represented by the above formulas (ca-1) is more preferable. And cations each represented by the above formulas (ca-1-1) to (ca-1-67) are more preferable.

(d1-1) A component may be used individually by 1 type, or may be used in combination of 2 or more types.

{(d1-2) component}

·· Anion part

In formula (d1-2), Rd ² is a cyclic group that may have a substituent, a chain alkyl group that may have a substituent, or a chain alkenyl group that may have a substituent, respectively, in formula (b-1) ), the same as R ¹⁰¹ in ).

However, in Rd ² , the fluorine atom is not bonded to the carbon atom adjacent to the S atom (it is not substituted with fluorine). Accordingly, the anion of component (d1-2) becomes an appropriate weak acid anion, and the quenching ability as component (D) is improved.

Rd ² is preferably a chain alkyl group which may have a substituent, or an aliphatic cyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, and more preferably has 3 to 10 carbon atoms. The aliphatic cyclic group includes groups obtained by removing one or more hydrogen atoms from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc. (may have a substituent); one or more groups from camphor, etc. It is more preferable that it is a group from which a hydrogen atom has been removed.

The hydrocarbon group of Rd ² may have a substituent, and the substituent may be a substituent that the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in Rd ¹ of the above formula (d1-1) may have. The same thing can be mentioned.

Below, preferred specific examples of the anion portion of component (d1-2) are shown.

[Formula 44]

·· Cation part

In formula (d1-2), M ^m+ is an m-valent organic cation, and is the same as M ^m+ in formula (d1-1).

(d1-2) A component may be used individually by 1 type, or may be used in combination of 2 or more types.

{(d1-3) component}

·· Anion part

In formula (d1-3), Rd ³ is a cyclic group that may have a substituent, a chain alkyl group that may have a substituent, or a chain alkenyl group that may have a substituent, respectively, formula (b-1) The same as R ¹⁰¹ can be mentioned, and it is preferably a cyclic group containing a fluorine atom, a chain alkyl group, or a chain alkenyl group. Among these, a fluorinated alkyl group is preferable, and the same fluorinated alkyl group of Rd ¹ is more preferable.

In formula (d1-3), Rd ⁴ is a cyclic group that may have a substituent, a chain alkyl group that may have a substituent, or a chain alkenyl group that may have a substituent, respectively, formula (b-1 ), the same as R ¹⁰¹ in ).

Among them, alkyl groups, alkoxy groups, alkenyl groups, and cyclic groups that may have substituents are preferable.

The alkyl group for Rd ⁴ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group. group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, etc. Part of the hydrogen atom of the alkyl group of Rd ⁴ may be substituted with a hydroxyl group, a cyano group, or the like.

The alkoxy group for Rd ⁴ is preferably an alkoxy group having 1 to 5 carbon atoms. Specifically, the alkoxy group having 1 to 5 carbon atoms includes methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, and n- Butoxy group and tert-butoxy group can be mentioned. Among them, methoxy group and ethoxy group are preferable.

The alkenyl group for Rd ⁴ may be the same as R ¹⁰¹ in the above formula (b-1), and vinyl group, propenyl group (allyl group), 1-methylpropenyl group, and 2-methylpropenyl group are preferred. . These groups may also have an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms as a substituent.

The cyclic group for Rd ⁴ includes the same group as R ¹⁰¹ in the above formula (b-1), and includes cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, and tetracyclo An alicyclic group obtained by removing one or more hydrogen atoms from a cycloalkane such as dodecane, or an aromatic group such as a phenyl group or a naphthyl group is preferable. When Rd ⁴ is an alicyclic group, the resist composition dissolves well in an organic solvent, thereby improving lithography characteristics. Moreover, when Rd ⁴ is an aromatic group, in lithography using EUV or the like as an exposure light source, the resist composition has excellent light absorption efficiency, and sensitivity and lithography characteristics become good.

In formula (d1-3), Yd ¹ is a single bond or a divalent linking group.

The divalent linking group for Yd ¹ is not particularly limited, but includes a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent, a divalent linking group containing a hetero atom, and the like.

Yd ¹ is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a straight-chain or branched alkylene group, and even more preferably a methylene group or an ethylene group.

Below, preferred specific examples of the anion portion of component (d1-3) are shown.

[Formula 45]

[Formula 46]

·· Cation part

In formula (d1-3), M ^m+ is an m-valent organic cation, and is the same as M ^m+ in formula (d1-1).

(d1-3) A component may be used individually by 1 type, or may be used in combination of 2 or more types.

As for the (D1) component, only one type among the components (d1-1) to (d1-3) above may be used, or two or more types may be used in combination.

Among the above, it is preferable to use at least (d1-1) component as the (D1) component.

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

When the content of component (D1) is equal to or more than the preferred lower limit, it is easy to obtain particularly good lithographic properties and resist pattern shape. On the other hand, if it is below the upper limit, sensitivity can be maintained well and throughput is also excellent.

(D1) Manufacturing method of ingredient:

The method for producing the above-mentioned component (d1-1) and component (d1-2) is not particularly limited, and they can be produced by a known method.

In addition, the method for producing component (d1-3) is not particularly limited, and for example, it is produced in the same manner as the method described in US2012-0149916.

· (D2) About the ingredients

The acid diffusion controller component may contain a nitrogen-containing organic compound component (hereinafter referred to as “component (D2)”) that does not correspond to the component (D1) above.

The component (D2) is not particularly limited as long as it acts as an acid diffusion controller and does not fall under the component (D1), and any known component may be used arbitrarily. Among these, aliphatic amines are preferable, and among these, secondary aliphatic amines and tertiary aliphatic amines are particularly preferable.

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

Examples of aliphatic amines include amines (alkylamines or alkylalcoholamines) or cyclic amines in which at least one hydrogen atom of ammonia NH ₃ is replaced with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.

Specific examples of alkylamine and alkylalcoholamine include monoalkylamine such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; diethylamine, di-n- Dialkylamines such as propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri- Tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, tri-n-dodecylamine, etc. Alkylamine; Alkyl alcohol amines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine can be mentioned. Among these, trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

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

Specific examples of aliphatic monocyclic amines include piperidine and piperazine.

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

Other aliphatic amines include tris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine, and 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, triethanolamine triacetate, etc., and triethanolamine triacetate is preferable.

Additionally, as the component (D2), you may use an aromatic amine.

Aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxycarbonylpyrrolidine, etc. can be mentioned.

(D2) A component may be used individually by 1 type, or may be used in combination of 2 or more types.

When the resist composition contains component (D2), component (D2) is usually used in the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of component (A). By setting it within the above range, the resist pattern shape, stability over time after exposure, etc. are improved.

[(E) Component: Organic carboxylic acid, and at least one compound selected from the group consisting of oxoacid of phosphorus and its derivatives]

In the resist composition of the present invention, for the purpose of preventing sensitivity deterioration, improving resist pattern shape, stability over time after exposure, etc., the group consisting of organic carboxylic acid, oxo acid of phosphorus, and its derivatives as optional components. At least one type of compound (E) (hereinafter referred to as “(E) component”) selected from can be contained.

Suitable organic carboxylic acids include, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, etc.

Examples of oxo acids of phosphorus include phosphoric acid, phosphonic acid, and phosphinic acid, and among these, phosphonic acid is particularly preferable.

Derivatives of phosphorus oxo acid include, for example, esters in which the hydrogen atom of the oxo acid is replaced with a hydrocarbon group, and the hydrocarbon group includes an alkyl group with 1 to 5 carbon atoms, an aryl group with 6 to 15 carbon atoms, etc. can be mentioned.

Derivatives of phosphoric acid include phosphoric acid esters such as di-n-butyl phosphoric acid ester and diphenyl phosphoric acid ester.

Derivatives of phosphonic acid include phosphonic acid esters such as dimethyl phosphonic acid, di-n-butyl phosphonic acid, phenylphosphonic acid, diphenyl phosphonic acid, and dibenzyl phosphonic acid.

Derivatives of phosphinic acid include phosphinic acid esters and phenylphosphinic acid.

(E) Component may be used individually by 1 type, or may use 2 or more types together.

When the resist composition contains component (E), component (E) is usually used in the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of component (A).

[(F) Ingredient: Fluorine additive component]

The resist composition of the present invention may contain a fluorine additive component (hereinafter referred to as “component (F)”) in order to impart water repellency to the resist film.

(F) Components include, for example, Japanese Patent Laid-Open No. 2010-002870, Japanese Patent Laid-Open No. 2010-032994, Japanese Patent Laid-Open No. 2010-277043, Japanese Patent Laid-Open No. 2011-13569, and Japanese Patent Laid-Open No. 2010-002870. The fluorinated polymer compound described in Publication No. 2011-128226 can be used. More specifically, the (F) component includes a polymer having a structural unit (f1) represented by the following formula (f1-1). However, polymer compounds corresponding to component (A) described above are excluded.

Examples of the polymer having the structural unit (f1) above include a polymer (homopolymer) consisting of only the structural unit (f1); a copolymer of the structural unit (f1) and the structural unit represented by the following formula (m-1); its composition A copolymer of the unit (f1), a structural unit derived from acrylic acid or methacrylic acid, and a structural unit represented by the following formula (m-1) is preferable.

Here, the structural unit represented by the formula (m-1) includes a structural unit derived from 1-ethyl-1-cyclooctyl (meth)acrylate, and a structural unit derived from 1-methyl-1-adamantyl (meth)acrylate. Derived structural units are preferred.

[Formula 47]

[In the formula, the plurality of R is each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. In formula (f1-1), Rf ¹⁰² and Rf ¹⁰³ each independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 5 carbon atoms, or a halogenated alkyl group with 1 to 5 carbon atoms, and Rf ¹⁰² and Rf ¹⁰³ may be the same or different. You can do it. nf ¹ is an integer of 0 to 5, and Rf ¹⁰¹ is an organic group containing a fluorine atom. In formula (m-1), R ²¹ is an alkyl group, and R ²² is a group that forms an aliphatic cyclic group together with the carbon atom to which R ²² is bonded.]

In the formula (f1-1), R is each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. R in the formula (f1-1) is the same as R in the formula (a1-1) described above.

R is preferably a hydrogen atom, an alkyl group with 1 to 5 carbon atoms, or a fluorinated alkyl group with 1 to 5 carbon atoms, and more preferably a hydrogen atom and an alkyl group with 1 to 5 carbon atoms due to ease of industrial availability. An alkyl group is more preferred, and a methyl group is particularly preferred.

In formula (f1-1), the halogen atom for Rf ¹⁰² and Rf ¹⁰³ includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and a fluorine atom is particularly preferable. Examples of the alkyl group having 1 to 5 carbon atoms for Rf ¹⁰² and Rf ¹⁰³ include the same alkyl groups having 1 to 5 carbon atoms for R, and a methyl group or an ethyl group is preferable. Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms for Rf ¹⁰² and Rf ¹⁰³ include groups in which some or all of the 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, and an iodine atom, and a fluorine atom is particularly preferable. Among them, Rf ¹⁰² and Rf ¹⁰³ are preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group is preferable.

In formula (f1-1), nf ¹ is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 0 or 1.

In formula (f1-1), Rf ¹⁰¹ is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom.

The hydrocarbon group containing a fluorine atom may be linear, branched, or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and more preferably 1 to 10 carbon atoms. Particularly desirable.

In addition, as for the hydrocarbon group containing a fluorine atom, it is preferable that 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more are fluorinated, and 60% or more are fluorinated. This is particularly desirable because it increases the hydrophobicity of the resist film during liquid immersion exposure.

Among them, as Rf ¹⁰¹ , a fluorinated hydrocarbon group having 1 to 5 carbon atoms is more preferable and is -CF ₃ , -CH ₂ -CF ₃ , -CH ₂ -CF ₂ -CF ₃ , -CH(CF ₃ ) ₂ , -CH ₂ -CH ₂ -CF ₃ , -CH ₂ -CH ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₃ are particularly preferred.

In formula (m-1), the alkyl group for R ²¹ may be linear, branched, or cyclic, and is preferably linear or branched. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, etc. are mentioned, and among these, methyl group, ethyl group, or n-butyl group is preferable, and methyl group or ethyl group is more preferable. The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably has 3 to 5 carbon atoms. Specifically, isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group, etc. are mentioned, and isopropyl group is especially preferable.

In formula (m-1), R ²² is a group that forms an aliphatic cyclic group together with the carbon atom to which R ²² is bonded. The aliphatic cyclic group formed by R ²² may be polycyclic or monocyclic. As the monocyclic aliphatic cyclic group, a group obtained by removing one or more hydrogen atoms from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 10 carbon atoms, and examples include cyclopentane, cyclohexane, and cyclooctane. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, for example, adamantane and norbornane. , isobornane, tricyclodecane, tetracyclododecane, etc.

The mass average molecular weight (Mw) of the component (F) (based on polystyrene conversion by gel permeation chromatography) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and most preferably 10,000 to 30,000. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent for use as a resist, and if it is above the lower limit of this range, the dry etching resistance and cross-sectional shape of the resist pattern are good.

(F) The dispersion degree (Mw/Mn) of component is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5.

(F) Component may be used individually by 1 type, or may use 2 or more types together.

When the resist composition contains component (F), component (F) is usually used in a ratio of 0.5 to 10 parts by mass with respect to 100 parts by mass of component (A).

The resist composition of the present invention further contains miscible additives as desired, such as additional resins, dissolution inhibitors, plasticizers, stabilizers, colorants, anti-halation agents, dyes, etc. to improve the performance of the resist film. You can do it.

[(S) component: organic solvent component]

The resist composition of the present invention can be produced by dissolving a resist material in an organic solvent component (hereinafter referred to as “(S) component”).

The (S) component may be any one that can dissolve each component used and form a uniform solution, and any solvent that is conventionally known as a solvent for chemically amplified resist compositions can be appropriately selected and used.

For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; ethylene glycol, diethylene glycol , polyhydric alcohols such as propylene glycol and dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, the polyhydric alcohols or the above esters Derivatives of polyhydric alcohols, such as monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, and monobutyl ether of compounds having a bond, or compounds having an ether bond such as monophenyl ether [among these, propylene glycol Monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; cyclic ethers such as dioxane, methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate , esters such as ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; anisole, ethylbenzyl ether, crezyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, ethylbenzene, diethyl Aromatic organic solvents such as benzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene, dimethyl sulfoxide (DMSO); Propylene carbonate, etc. can be mentioned.

(S) Component may be used individually by 1 type, or may be used as a mixed solvent of 2 or more types.

Among them, PGMEA, PGME, γ-butyrolactone, EL (ethyl lactate), cyclohexanone, and propylene carbonate are preferable.

Additionally, a mixed solvent in which PGMEA and a polar solvent are mixed is also preferable. The mixing ratio (mass ratio) can be determined appropriately taking into account the compatibility of PGMEA with the polar solvent, etc., and is preferably within the range of 1:9 to 9:1, more preferably within the range of 2:8 to 8:2. desirable.

More specifically, when mixing EL or cyclohexanone as a polar solvent, the mass ratio of PGMEA:EL (ethyl lactate) or cyclohexanone is preferably 1:9 to 9:1, more preferably 2:1. It is 8 to 8:2. In addition, when mixing PGME as a polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, more preferably 2:8 to 8:2, and even more preferably 3:7 to 3:7. It is 7:3. Additionally, a mixed solvent of PGMEA, PGME, and cyclohexanone is also preferred.

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

The amount of component (S) used is not particularly limited, and is appropriately set to a concentration that can be applied to a substrate or the like, depending on the coating film thickness. In general, the (S) component is used so that the solid content concentration of the resist composition is in the range of 1 to 20% by mass, preferably 2 to 15% by mass.

According to the resist pattern forming method using the resist composition of the embodiment described above, the effect of having better CDU is obtained.

<Method of forming resist pattern>

A resist pattern forming method, which is a second aspect of the present invention, includes the steps of forming a resist film using the resist composition described in the first aspect, exposing the resist film, and developing the resist film to form a resist pattern. do.

More specifically, the method for forming a resist pattern includes forming a resist film on a support using a resist composition that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid; It includes a step of exposing the resist film, and a step of patterning the exposed resist film by development using a developer to form a resist pattern.

This resist pattern formation method can be performed, for example, as follows.

First, a resist composition that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid is applied to the support using a spinner or the like, followed by a bake (Post Apply Bake (PAB)) treatment. , for example, at a temperature of 80 to 150°C for 40 to 120 seconds, preferably 60 to 90 seconds, to form a resist film.

For the resist composition here, the resist composition described above is used.

Next, the resist film is exposed through a photomask (mask pattern) on which a predetermined pattern is formed using an exposure device such as an ArF exposure device, an electron beam drawing device, or an EUV exposure device, or a photomask. Selective exposure is performed by drawing by direct irradiation of electron beam without intervening.

After that, a bake (Post Exposure Bake (PEB)) process is performed, for example, for 40 to 120 seconds under temperature conditions of 80 to 150°C, and preferably for 60 to 90 seconds.

Next, the resist film after the above exposure and bake (PEB) treatment is developed. In the case of an alkaline development process, an alkaline developer is used, and in the case of a solvent development process, a developer containing an organic solvent (organic developer) is used.

After development, a rinse treatment is preferably performed. In the case of an alkaline development process, water rinsing using pure water is preferable, and in the case of a solvent development process, it is preferable to use a rinse solution containing an organic solvent.

In the case of the solvent development process, after the development or rinsing process, a process of removing the developer or rinse liquid adhering to the pattern with a supercritical fluid may be performed.

Drying is performed after development or rinsing. Additionally, depending on the case, a bake treatment (post-bake) may be performed after the development treatment. In this way, a resist pattern can be obtained.

By performing the above operation, a fine resist pattern can be formed.

The support is not particularly limited, and conventionally known ones can be used. For example, a substrate for electronic components or a substrate on which a predetermined wiring pattern is formed can be used. More specifically, examples include silicon wafers, metal substrates such as copper, chrome, iron, and aluminum, and glass substrates. Materials for the wiring pattern include, for example, copper, aluminum, nickel, and gold.

Additionally, the support may be one in which an inorganic and/or organic film is formed on a substrate as described above. Examples of inorganic films include inorganic antireflection films (inorganic BARC). Examples of organic films include organic anti-reflection films (organic BARC) and organic films such as the lower layer organic film in the multilayer resist method.

Here, the multilayer resist method refers to forming at least one layer of organic film (lower layer organic film) and at least one layer of resist film (upper layer resist film) on a substrate, and using the resist pattern formed on the upper resist film as a mask. This is a method of patterning the lower organic layer, and is believed to be capable of forming a pattern with a high aspect ratio. That is, according to the multilayer resist method, the required thickness can be secured by the lower organic film, so the resist film can be made thin, and fine patterns with high aspect ratios can be formed.

The multilayer resist method basically includes a method of forming a two-layer structure of an upper resist film and a lower layer organic film (two-layer resist method), and a method of forming one or more intermediate layers (metal thin film, etc.) between the upper resist film and the lower organic film. It is divided into a method of forming a multi-layer structure of three or more layers (three-layer resist method).

The wavelength used for exposure is not particularly limited and includes ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet ray), VUV (vacuum ultraviolet ray), EB (electron beam), X-ray, soft X It can be performed using radiation such as a line. The resist pattern forming method of the present invention is highly useful for KrF excimer laser, ArF excimer laser, EB or EUV, and is particularly useful for ArF excimer laser, EB or EUV.

The exposure method for the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or liquid immersion exposure (liquid immersion lithography).

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

As the immersion medium, a solvent having a refractive index greater than the refractive index of air and smaller than the refractive index of the resist film to be exposed is preferable. The refractive index of this solvent is not particularly limited as long as it is within the above range.

Examples of solvents having a refractive index greater than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based organic solvent, and a hydrocarbon-based organic solvent.

Specific examples of fluorine-based inert liquids include liquids containing fluorine-based compounds such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as main components. The boiling point is preferably 70 to 180°C, and more preferably 80 to 160°C. If the fluorine-based inert liquid has a boiling point in the above range, it is preferable because the medium used for liquid immersion can be removed in a simple manner after completion of exposure.

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

Additionally, specifically, the perfluoroalkyl ether compound includes perfluoro(2-butyl-tetrahydrofuran) (boiling point 102°C), and the perfluoroalkylamine compound includes perfluoro(2-butyl-tetrahydrofuran) (boiling point 102°C). and rotributylamine (boiling point 174°C).

As an immersion medium, water is preferably used from the viewpoints of cost, safety, environmental issues, versatility, etc.

The alkaline developing solution used for development in the alkaline developing process can be appropriately selected from known alkaline developing solutions. For example, a 0.1 to 10% by mass tetramethylammonium hydroxide (TMAH) aqueous solution can be used.

The organic solvent contained in the organic developer used for development in the solvent development process can be appropriately selected from known organic solvents. Specific examples include polar solvents such as ketone-based organic solvents, ester-based organic solvents, alcohol-based organic solvents, nitrile-based organic solvents, amide-based organic solvents, and ether-based organic solvents, and hydrocarbon-based organic solvents. Additionally, the developer may contain 80 mass% or more of an organic solvent.

A ketone-based organic solvent is an organic solvent containing C-C(=O)-C in its structure. An ester-based organic solvent is an organic solvent containing C-C(=O)-O-C in its structure. An alcoholic organic solvent is an organic solvent containing an alcoholic hydroxyl group in its structure, and “alcoholic hydroxyl group” means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. A nitrile-based organic solvent is an organic solvent containing a nitrile group in its structure. An amide-based organic solvent is an organic solvent containing an amide group in its structure. An etheric organic solvent is an organic solvent containing C-O-C in its structure.

Among organic solvents, there are also organic solvents that contain multiple types of functional groups that characterize each of the above-mentioned solvents in their structure, but in that case, it is assumed that this applies to any solvent species containing the functional group possessed by the organic solvent. For example, diethylene glycol monomethyl ether is assumed to correspond to either alcohol-based organic solvent or ether-based organic solvent in the above classification.

The hydrocarbon-based organic solvent is a hydrocarbon solvent that is composed of hydrocarbons that may be halogenated and does not have substituents other than halogen atoms. Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms being preferred.

Among the above, the developer used for development in the solvent development process preferably contains at least one selected from the group consisting of ester-based organic solvents and ketone-based organic solvents, since it is easy to obtain a high-resolution resist pattern, It is more preferable to contain an ester-based organic solvent.

Ester-based organic solvents include, for example, methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate, and 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, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxy Butyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxy Pentyl 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 lactate. , ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, 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-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, etc. there is.

Among the above, butyl acetate is preferable as the ester-based organic solvent.

Ketone-based organic solvents include, for example, 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, and diiso. Butyl ketone, cyclohexanone, methyl cyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone. , isophorone, propylene carbonate, γ-butyrolactone, methyl amyl ketone (2-heptanone), etc.

Among the above, methyl amyl ketone (2-heptanone) is preferable as the ketone organic solvent.

Known additives can be added to the organic developer as needed. Examples of the additive include surfactants. The surfactant is not particularly limited, but for example, ionic or nonionic fluorine-based and/or silicon-based surfactants can be used.

As the surfactant, nonionic surfactants are preferable, and fluorine-based surfactants or silicone-based surfactants are more preferable.

When blending a surfactant with an organic developer, the blending amount is usually 0.001 to 5 mass%, preferably 0.005 to 2 mass%, and more preferably 0.01 to 0.5 mass%, relative to the total amount of the organic developer.

The development process can be performed by a known developing method, for example, a method of immersing the support in a developing solution for a certain period of time (dip method), a method of mounting the developer on the surface of the support by surface tension and stopping it for a certain period of time ( Paddle method), a method of spraying developer on the surface of a support (spray method), a method of continuously dispensing developer while scanning a nozzle that dispenses developer at a constant speed on a support rotating at a constant speed (dynamic dispensing method) ), etc.

As the organic solvent contained in the rinse solution used for the post-development rinse treatment in the solvent development process, for example, one that does not easily dissolve the resist pattern is appropriately selected from among the organic solvents exemplified as organic solvents used in the above organic developer solution. You can use it. Typically, at least one type of solvent selected from hydrocarbon-based organic solvents, ketone-based organic solvents, ester-based organic solvents, alcohol-based organic solvents, amide-based organic solvents, and ether-based organic solvents is used. Among these, at least one type selected from hydrocarbon-based organic solvents, ketone-based organic solvents, ester-based organic solvents, alcohol-based organic solvents and amide-based organic solvents is preferred, and at least one type selected from ester-based organic solvents and ketone-based organic solvents. One type is more preferable, and an ester-based organic solvent is particularly preferable.

These organic solvents may be used individually, or two or more types may be used in mixture. Additionally, it may be used by mixing with organic solvents other than the above or water. However, considering the development characteristics, the water content in the rinse liquid is preferably 30% by mass or less, more preferably 10% by mass or less, more preferably 5% by mass or less, and 3% by mass or less, relative to the total amount of the rinse liquid. % or less is particularly preferable.

Known additives can be added to the rinse liquid as needed. Examples of the additive include surfactants. Surfactants include the same surfactants as described above, nonionic surfactants are preferred, and fluorine-based surfactants or silicone-based surfactants are more preferred.

When adding a surfactant, the amount added 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, relative to the total amount of rinse liquid.

Rinsing treatment (cleaning treatment) using a rinse liquid can be performed by a known rinsing method. The method includes, for example, a method of continuously drawing a rinse solution onto a support rotating at a constant speed (rotation application method), a method of immersing the support in a rinse solution for a certain period of time (dip method), and applying the rinse solution to the surface of the support. A method of spraying (spray method), etc.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Preparation of resist composition>

The resist compositions of each example were prepared by mixing and dissolving each component as shown in Table 1 below.

(A) Ingredient (B) Ingredient (D) Ingredient (F)Ingredients (S)Ingredients Example 1 R.A.
[100] PA
[11] QA
[6.3] - PGMEA/PGME(70/30)
[3000] Example 2 R.A.
[100] PA
[11] QA
[6.3] FA
[One] PGMEA/PGME(70/30)
[3000] Example 3 RB
[100] PA
[11] QA
[6.3] - PGMEA/PGME(70/30)
[3000] Example 4 RB
[100] PA
[11] QA
[6.3] FA
[One] PGMEA/PGME(70/30)
[3000] Example 5 R.C.
[100] PA
[14] QA
[4] - PGMEA/PGME(70/30)
[3000] Comparative Example 1 R.D.
[100] PA
[11] QA
[6.3] FA
[One] PGMEA/PGME(70/30)
[3000] Comparative Example 2 R.D.
[100] PA
[14] QA
[4] FA
[One] PGMEA/PGME(70/30)
[3000] Comparative Example 3 R.E.
[100] PA
[11] QA
[6.3] FA
[One] PGMEA/PGME(70/30)
[3000]

In Table 1 above, each abbreviation has the following meaning, and the numerical value in [] is the mixing amount (parts by mass).

(A) Ingredient

Polymer compounds R-A to R-E in Table 2 below.

Polymer compounds R-A to R-E were obtained by radical polymerization using the following monomers M-1 to M-3 and M-f, which provide structural units constituting each polymer compound, at a predetermined molar ratio shown in Table 2 above.

[Formula 48]

M-1 M-2 M-3 M-f

In Table 2 above, the copolymer composition ratio (molar ratio of each structural unit in the polymer compound) of each polymer compound was determined by ¹³ C-NMR, and the molecular weight (Mw) was the mass average of polystyrene conversion by GPC (gel permeation chromatography). It is expressed using molecular weight.

(B) Ingredient

P-A: Acid generator represented by the following chemical formula.

[Formula 49]

(D) Ingredient

Q-A: An acid diffusion control agent represented by the following chemical formula.

[Formula 50]

(F) Ingredient

FA: A fluorinated polymer compound represented by the following chemical formula. The mass average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 15000, and the molecular weight dispersion (Mw/Mn) was 1.61. ¹³ The copolymer composition ratio (molar ratio of each structural unit in the structural formula) determined by C-NMR is l/m = 50/50.

[Formula 51]

(S) Ingredient

PGMEA: propylene glycol monomethyl ether acetate

PGME: propylene glycol monomethyl ether

<Formation of negative resist pattern>

On a 12-inch silicon wafer, an organic anti-reflective coating composition "ARC95" (brand name, manufactured by Brewer Science) was applied using a spinner, baked at 205°C for 60 seconds on a hot plate, and dried to form an organic anti-reflective coating composition with a film thickness of 98 nm. An antireflection film was formed.

Next, the resist compositions shown in Table 1 above were applied onto this film using a spinner, and post-apply bake (PAB) treatment was performed on a hot plate at a temperature of 100°C for 60 seconds, followed by drying. By doing this, a resist film with a film thickness of 90 nm was formed.

Next, a photomask was applied to the resist film using an ArF exposure device NSR-S610C [manufactured by Nikon; NA (numerical aperture) = 1.30, Crosspole (0.78-0.97) with POLANO, immersion medium: water]. Intervening, each was selectively irradiated with an ArF excimer laser (193 nm).

After that, post exposure bake (PEB) treatment was performed at 90°C for 60 seconds.

Next, solvent development was performed at 23°C for 30 seconds using butyl acetate, followed by rinsing treatment.

As a result, a contact hole pattern with a hole diameter of 45 nm/pitch of 90 nm (mask size 63 nm) was formed.

A negative resist pattern was formed.

<Evaluation of negative resist pattern>

[Evaluation of CDU (in-plane uniformity of pattern dimensions) characteristics]

100 holes in the CH pattern were observed from above with a measurement SEM (scanning electron microscope, acceleration voltage 300 V, brand name: S-9380, manufactured by Hitachi High Technologies), and the hole diameter (nm) of each hole was measured. A value (3σ) that is three times the standard deviation (σ) calculated from the measurement results was obtained. The results are shown in [Table 3] as “CDU”.

The smaller the value of 3σ determined in this way, the higher the uniformity of the hole dimensions (CD) of the plurality of holes formed in the resist film.

resist pattern CDU Example 1 3.88 Example 2 3.86 Example 3 4.01 Example 4 3.96 Example 5 4.1 Comparative Example 1 4.32 Comparative Example 2 4.45 Comparative Example 3 4.6

From the results shown in Table 3, it can be seen that the resist patterns formed using the resist compositions of Examples 1 to 5 have lower CDU (3σ) values than the resist patterns formed using the resist compositions of Comparative Examples 1 to 3. From this, it can be seen that the resist composition according to the present invention can form a pattern with high in-plane uniformity of the resist film.

<Evaluation of the teaching (elution) characteristics of the resist film>

The dissolution characteristics of the resist composition shown in Table 1 were measured by the WEXA method (W. Hinsberg et al., SPIE 2004 vol. 5376, 21), a standardized method in the lithography field. The resist composition shown in Table 1 above was applied onto the wafer, and a bake treatment was performed at a temperature of 100°C for 60 seconds to obtain a resist film with a film thickness of 85 nm. After that, the WEXA jig was brought into contact with the wafer, and pure water was poured into the jig. Pure water was recovered and the elution amount analyzed by LC-MS was determined. The results are shown in [Table 4] as “dissolution amount”.

resist composition Dissolution amount
(E-12mol/cm ² · s) Example 1 0.32 Example 2 0.16 Example 3 0.31 Example 4 0.15 Example 5 0.28 Comparative Example 1 0.45 Comparative Example 2 0.46 Comparative Example 3 0.4

From the results shown in Table 4, it can be seen that the amount of elution of the resist films formed using the resist compositions of Examples 1 to 5 is less than that of the resist films formed using the resist compositions of Comparative Examples 1 to 3, and from this, the present invention It can be seen that the following composition can reduce the problem of dissolution during liquid immersion exposure.

Therefore, the resist composition of the present invention and the method of forming a resist pattern using the same make it possible to simultaneously achieve two tasks: improving the in-plane uniformity of pattern dimensions and reducing the problem of dissolution during immersion exposure.

Claims (10)

A resist composition comprising a component (A) whose solubility in a developer changes by the action of an acid and an acid generator component (B) which generates an acid upon exposure,
The component (A) contains a polymer compound (A1) having a structural unit (a1) represented by the following formula (a1-1) and a structural unit (af) containing a fluorine atom, and contains the fluorine atom. A resist composition wherein the unit (af) is represented by the following formula (af-1), and the structural unit (af) in the polymer compound (A1) is 1 to 15 mol%.
(a1-1)
[In formula (a1-1), R represents a hydrogen atom, an alkyl group, or a halogenated alkyl group; Z represents a single bond or an alkylene group; C _P is (Here, R ₂ is a tertiary alkyl group, n _p is a positive integer, and * indicates a bonding position).]

(af-1)
[In formula (af-1), R represents a hydrogen atom or a methyl group, and Y represents a linear or branched alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with a fluorine atom; or a divalent group selected from the group consisting of -C(=O)-O- and -C(=O)-; _{Or represents a combination thereof , and _ _ _ _} It represents a group selected from the group consisting of -CH ₂ -CH ₂ -CF ₂ -CF ₂ -CF ₂ -CF _3. ] According to claim 1,
A resist composition wherein n _p is 1 and R ₂ is a tert-butyl group. delete delete According to claim 1,
A resist composition wherein the polymer compound (A1) of the component (A) further has a structural unit (a2) containing a lactone cyclic group or a sulfone cyclic group. According to claim 1,
A resist composition containing one or more components selected from the group consisting of acid diffusion control agents, additives, and solvents. According to any one of claims 1, 2, 5 and 6,
A resist composition containing no fluorinated additives. A step of forming a resist film on a support using the resist composition according to any one of claims 1, 2, 5, and 6, exposing the resist film to light, and developing the resist film to form a resist. A resist pattern forming method including a pattern forming process. According to claim 8,
A method of forming a resist pattern, wherein the exposure is liquid immersion exposure. According to claim 8,
A resist pattern forming method in which an organic solvent is used as a developer.