JP6643833B2 - Resist pattern forming method, resist pattern splitting agent, split pattern improving agent, and resist pattern split material - Google Patents

Description

  The present invention relates to a resist pattern forming method, a resist pattern splitting agent, a split pattern improving agent, and a resist pattern split material.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to radiation such as light or an electron beam through a mask in which a predetermined pattern is formed. Then, a developing process is performed to form a resist pattern having a predetermined shape on the resist film.
A resist material whose exposed part changes to a property of dissolving in a developing solution is called a positive type, and a resist material whose exposed part changes to a property of not dissolving in a developing solution is called a negative type.
2. Description of the Related Art In recent years, in the production of semiconductor devices and liquid crystal display devices, finer patterns have been rapidly advanced due to advances in lithography technology.
As a method of miniaturization, generally, the wavelength of an exposure light source is shortened (energy is increased). Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but now, mass production of semiconductor devices using a KrF excimer laser or an ArF excimer laser has started. Also, electron beams having shorter wavelengths (higher energy) than these excimer lasers, EUV (extreme ultraviolet rays), X-rays, and the like have been studied.

  As a technique for providing a finer pattern, a double patterning process of forming a resist pattern by performing patterning a plurality of times has been proposed. According to the double patterning process, for example, after forming a first resist pattern by performing patterning using a first resist composition on a support, the first resist pattern is formed. By performing patterning on the support using the second resist composition, a resist pattern having a higher resolution than a resist pattern formed by one patterning can be formed.

Further, in Patent Document 1, a first resist pattern is formed on a support, an SiO ₂ film is formed on the surface of the support and the first resist pattern, and etching is performed using the SiO ₂ film as a sacrificial film. Then, a method of forming a second pattern of the SiO ₂ film by removing the first resist pattern is described.

JP 2013-164509 A

However, the above-described method has problems that a plurality of exposures are required, the number of steps is large, and the processing is complicated, and there is still room for improvement in the method of forming a fine pattern.
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a pattern forming method capable of forming a fine pattern in a simple process.

In a first aspect of the present invention, a step A of forming a first resist pattern on a support by forming a positive resist film, exposing the positive resist film to light, and alkali developing to form a first resist pattern; Step B of forming a first layer by applying a solution containing an acid or a thermal acid generator so as to cover the first resist pattern, and applying a solution containing a solvent so as to cover the first layer And heating the structure including the first resist pattern obtained in the steps A to C, and dissolving the first resist pattern in a developer by the action of an acid in the first layer. A step D of changing the solubility, and developing the coated first resist pattern with an organic solvent to remove a region other than a region where the solubility of the first resist pattern in a developing solution has changed, Step of forming a pattern And having a, when a resist pattern forming method.
A second aspect of the present invention is a resist pattern splitting agent used for coating a resist pattern and splitting the resist pattern, comprising at least a solvent and an acid or a thermal acid generator. Resist pattern splitting agent.
A third aspect of the present invention is a split pattern improving agent for coating a resist pattern after coating with the resist pattern splitting agent, further comprising at least an organic solvent and an acid diffusion controlling agent. Is a split pattern improving agent.
A fourth aspect of the present invention is a resist pattern splitting material comprising the resist pattern splitting agent of the second aspect of the present invention and the split pattern improving agent of the third aspect of the present invention.

  According to the present invention, it is possible to provide a pattern forming method capable of forming a fine pattern by a simple process.

FIG. 3 is a diagram illustrating an example of a schematic process of a method for forming a resist pattern of the present invention.

In the present specification and claims, the term "aliphatic" is a concept relative to aromatics, and is defined as meaning a group, compound, or the like having no aromaticity.
“Alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
The “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups unless otherwise specified. The same applies to the alkyl group in the alkoxy group.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of an alkyl group have been substituted 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 part or all of the hydrogen atoms of an alkyl group or an alkylene group have been substituted with fluorine atoms.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
The “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid ester” is a compound in which the hydrogen atom at the terminal of the carboxy group of acrylic acid (CH ₂ ＣＨCH—COOH) is substituted with an organic group.
In the acrylic ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent (R ^α ) for substituting a hydrogen atom bonded to the carbon atom at the α-position is an atom or a group other than a hydrogen atom, for example, an alkyl group having 1 to 5 carbon atoms or a halogenated group having 1 to 5 carbon atoms. Examples thereof include an alkyl group and a hydroxyalkyl group. The carbon atom at the α-position of the acrylate ester is a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
Hereinafter, an acrylate in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with a substituent may be referred to as an α-substituted acrylate. In addition, acrylates and α-substituted acrylates may be collectively referred to as “(α-substituted) acrylates”.
“Structural unit derived from hydroxystyrene or a hydroxystyrene derivative” means a structural unit constituted by cleavage of an ethylenic double bond of hydroxystyrene or a hydroxystyrene derivative.
The term “hydroxystyrene derivative” is a concept including those in which the hydrogen atom at the α-position of hydroxystyrene is substituted with another substituent such as an alkyl group or a halogenated alkyl group, and derivatives thereof. As those derivatives, those in which the hydrogen atom of the hydroxyl group of hydroxystyrene in which the hydrogen atom at the α-position may be substituted with an organic group are substituted with an organic group, and those in which the hydrogen atom at the α-position is substituted with a substituent Those in which a substituent other than a hydroxyl group is bonded to a benzene ring of good hydroxystyrene, and the like. The α-position (α-position carbon atom) means a carbon atom to which a benzene ring is bonded, unless otherwise specified.
Examples of the substituent that substitutes the hydrogen atom at the α-position of hydroxystyrene include the same substituents as those described as the substituent at the α-position in the α-substituted acrylate.
"Structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative" means a structural unit formed by cleavage of an ethylenic double bond of vinylbenzoic acid or a vinylbenzoic acid derivative.
The “vinyl benzoic acid derivative” is a concept including those in which the α-position hydrogen atom of vinyl benzoic acid is substituted with another substituent such as an alkyl group or a halogenated alkyl group, and derivatives thereof. These derivatives include those in which the hydrogen atom of the carboxy group of vinylbenzoic acid, in which the hydrogen atom at the α-position may be substituted with a substituent, is substituted with an organic group, and the hydrogen atom at the α-position is substituted with a substituent. And those in which a substituent other than a hydroxyl group and a carboxy group is bonded to the benzene ring of the vinyl benzoic acid which may be used. The α-position (α-position carbon atom) means a carbon atom to which a benzene ring is bonded, unless otherwise specified.
“Styrene derivative” means a compound in which the hydrogen atom at the α-position of styrene is substituted with another substituent such as an alkyl group or a halogenated alkyl group.
“Structural unit derived from styrene” and “structural unit derived from a styrene derivative” mean a structural unit formed by cleavage of an 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, specifically, an alkyl group having 1 to 5 carbon atoms (a methyl group, an ethyl group, a propyl group, an isopropyl group). , N-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group) and the like.
Examples of the halogenated alkyl group as a substituent at the α-position include a group in which part or all of the hydrogen atoms of the above “alkyl group as a substituent at the α-position” are substituted with a halogen atom. Can be 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.
Specific examples of the hydroxyalkyl group as the substituent at the α-position include a group in which part or all of the hydrogen atoms of the above “alkyl group as the substituent at the α-position” are substituted with a hydroxyl group. The number of hydroxyl groups in the hydroxyalkyl group is preferably from 1 to 5, and most preferably 1.
Be referred to as a "may have a substituent", the case of replacing a hydrogen atom (-H) a monovalent group, methylene group - when substituting a divalent radical (-CH ₂₎ Including both.
“Exposure” is a concept including radiation irradiation in general.

≪Method of forming resist pattern≫
In the present invention, a step A of forming a positive resist film on a support, exposing the positive resist film to light, and developing with alkali to form a first resist pattern; A step B of forming a first layer by applying a solution containing an acid or a thermal acid generator so as to cover the layer, and a step C of applying a solution containing a solvent so as to cover the first layer; Heating the structure including the first resist pattern obtained in the steps A to C, and changing the solubility of the first resist pattern in a developer by the action of an acid in the first layer; D, a step of developing the coated first resist pattern with an organic solvent to remove a region other than a region in which the solubility of the first resist pattern in a developer has changed to form a second resist pattern With E Characterized in that, a resist pattern forming method.
Hereinafter, the resist pattern forming method of the present invention will be described with reference to the drawings.

FIG. 1 shows schematic steps of a method for forming a resist pattern according to the first embodiment. 1A to 1E show cross sections of the resist pattern.
First, as shown in FIG. 1A, a line-and-space resist pattern 2 is formed on a support 1 using the positive resist composition (step A).
Next, as shown in FIG. 1B, a solution containing an acid or a thermal acid generator is applied so as to cover the resist pattern 2, and the first resist pattern 2 and the first layer covering the same are coated. 3 is obtained (step B).
Next, as shown in FIG. 1C, a solution containing a solvent is applied so as to cover the structure, and a layer 4 of the solution containing the solvent is formed (Step C).
Thereafter, the structure including the first resist pattern obtained in steps A to C is heated to change the solubility of the surface of the first resist pattern 2 in the developing solution as shown in FIG. (Step D).
Thereafter, organic solvent development is performed to remove the portion indicated by 2b in FIG. 1D, thereby dividing the first resist pattern into lines, spaces, and lines as shown in FIG. 1E. ) Is formed (step E).

[Step A]
Step A is a step of forming a positive resist film on a support, exposing the positive resist film, and developing with an alkali to form a first resist pattern. In step A, a first resist pattern 2 is formed on a support 1 as shown in FIG.
(Support)
The support is not particularly limited, and a conventionally known support can be used, and examples thereof include a substrate for an electronic component and a support on which a predetermined wiring pattern is formed. More specifically, examples include a silicon wafer, a substrate made of metal such as copper, chromium, iron, and aluminum, and a glass substrate. As a material of the wiring pattern, for example, copper, aluminum, nickel, gold and the like can be used.
Further, as the support, a substrate provided with an inorganic and / or organic film on the above-described substrate may be used. Examples of the inorganic film include an inorganic anti-reflection film (inorganic BARC). Examples of the organic film include an organic film such as an organic antireflection film (organic BARC) and a lower organic film in a multilayer resist method.
Here, the multilayer resist method means that at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and a resist pattern formed on the upper resist film is used as a mask. This is a method of patterning a lower organic film, and it is said that a pattern having a high aspect ratio can be formed. That is, according to the multilayer resist method, the required thickness can be secured by the lower organic film, so that the resist film can be made thinner and a fine pattern with a high aspect ratio 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 organic film (a two-layer resist method), and a method of forming one or more intermediate layers between the upper resist film and the lower organic film. (Three-layer resist method) in which a multilayer structure having three or more layers provided with (a metal thin film or the like) is provided.

Wavelength used for the exposure is not particularly limited, ArF excimer laser, KrF excimer laser, _{F 2} excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-rays, and soft X-rays It can be performed using radiation. The resist composition is highly useful for KrF excimer laser, ArF excimer laser, EB or EUV.

The exposure method of the resist film may be ordinary exposure (dry exposure) performed in an inert gas such as air or nitrogen, or liquid immersion exposure (Liquid Immersion Lithography).
In the immersion exposure, the space between the resist film and the lens at the lowest position of the exposure apparatus is filled in advance with a solvent (immersion medium) having a refractive index larger than that of air, and exposure (immersion exposure) is performed in that state. Exposure method.
As the immersion medium, a solvent having a refractive index larger 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 such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger 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 solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorine-based inert liquid include a fluorine-based compound such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , C ₅ H ₃ F ₇ as a main component. Liquids and the like are mentioned, and those having a boiling point of 70 to 180 ° C are preferable, and those having a boiling point of 80 to 160 ° C are more preferable. It is preferable that the fluorinated inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of an alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, the perfluoroalkyl ether compound includes perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ° C.), and the perfluoroalkylamine compound includes perfluorotributylamine ( (Boiling point: 174 ° C.).
As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental issues, versatility and the like.

  Examples of the alkali developing solution used for the developing treatment in the alkali developing process include a 0.1 to 10% by mass aqueous solution of tetramethylammonium hydroxide (TMAH).

  The developing treatment can be performed by a known developing method. For example, a method in which a support is immersed in a developer for a certain period of time (dip method); Method (paddle method), method of spraying the developer on the surface of the support (spray method), application of the developer while scanning the developer application nozzle at a constant speed on the support rotating at a constant speed Continued method (dynamic dispensing method) and the like.

  The rinsing treatment (rinsing treatment) using the rinsing liquid can be performed by a known rinsing method. Examples of the method include a method of continuously applying a rinsing liquid onto a support rotating at a constant speed (rotation coating method), a method of dipping the support in a rinsing liquid for a predetermined time (dip method), and a method of applying a support surface. And a method of spraying a rinsing liquid (spray method).

<Positive resist composition>
In the step A, as the positive resist composition used for forming the first resist pattern, a positive resist composition that generates an acid upon exposure and increases the solubility in a developer due to the action of the acid can be used. .
The positive resist composition (hereinafter sometimes referred to as a “resist composition”) is a base component (A) whose solubility in a developing solution is changed by the action of an acid (hereinafter, “component (A)”). ) Is preferably contained.
When a resist film is formed using such a resist composition and the resist film is selectively exposed, an acid is generated in an exposed portion, and the action of the acid causes the solubility of the component (A) in an alkali developing solution. On the other hand, since the solubility of the component (A) in the alkali developing solution does not change in the unexposed portion, there is a difference in the solubility in the developing solution between the exposed portion and the unexposed portion. Therefore, when the resist film is developed, the exposed portions are dissolved and removed, and a positive resist pattern is formed.

In the present invention, the resist composition has an acid generating ability to generate an acid upon exposure, and the component (A) may generate an acid upon exposure, and may be added separately from the component (A). The agent component may generate an acid upon exposure.
Specifically, in the present invention, the resist composition,
(1) It may contain an acid generator component (B) that generates an acid upon exposure (hereinafter referred to as “component (B)”);
(2) The component (A) may be a component that generates an acid upon exposure;
(3) The component (A) may be a component that generates an acid upon exposure, and may further contain the component (B).
That is, in the case of the above (2) and (3), the component (A) is a “base component that generates an acid upon exposure and changes the solubility in a developer by the action of an acid”. When the component (A) is a base component that generates an acid upon exposure and increases the solubility in a developer due to the action of the acid, the component (A1) described below generates an acid upon exposure, and It is preferable to use a polymer compound whose solubility in a developer is increased by the action of an acid. As such a polymer compound, a resin having a structural unit that generates an acid upon exposure can be used. As the structural unit that generates an acid upon exposure, a known unit can be used.
In the present invention, the resist composition is particularly preferably the case of the above (1).

<(A) component>
In the present invention, the “base component” is an organic compound having a film-forming ability, and preferably an organic compound having 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, a nano-level photosensitive resin pattern is easily formed.
Organic compounds used as the base component are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, the “low molecular weight compound” refers to a non-polymer having a molecular weight of 500 or more and less than 4000.
As the polymer, those having a molecular weight of 1,000 or more are usually used. Hereinafter, the term “resin” refers to a polymer having a molecular weight of 1,000 or more.
As the molecular weight of the polymer, a weight average molecular weight in terms of polystyrene by GPC (gel permeation chromatography) is used.
As the component (A), a resin, a low molecular weight compound, or a combination of these may be used.
The component (A) increases the solubility in a developer by the action of an acid.
In the present invention, the component (A) may generate an acid upon exposure.

  In the present invention, the component (A) includes a structural unit containing an acid-decomposable group whose polarity increases by the action of an acid (hereinafter, may be referred to as a “structural unit (a1)”) and a lactone-containing cyclic group or carbonate. It preferably contains a polymer compound (A1) having a structural unit containing a cyclic group (hereinafter may be referred to as a “structural unit (a2)”).

(Structural unit (a1))
The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity is increased by the action of an acid.
An “acid-decomposable group” is an acid-decomposable group capable of cleaving at least a part of bonds in the structure of the acid-decomposable group by the action of an acid.
Examples of the acid-decomposable group whose polarity is increased by the action of an acid include a group which is decomposed by the action of an acid to generate a polar group.
Examples of the polar group include a carboxy group, a hydroxyl group, an amino group, a sulfo group (—SO ₃ H) and the like. Among these, a polar group containing -OH in the structure (hereinafter sometimes referred to as an "OH-containing polar group") is preferable, a carboxy group or a hydroxyl group is preferable, and a carboxy group is particularly preferable.
More specifically, examples of the acid-decomposable group include a group in which the polar group is protected by an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected by an acid-dissociable group).
Here, the “acid dissociable group”
(I) an acid-dissociable group capable of cleaving a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group by the action of an acid; or
(Ii) a group capable of cleaving a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group by further decarboxylation after partial bond cleavage by the action of an acid; ,
Means both.
The acid-dissociable group constituting the acid-decomposable group needs to be a group having a polarity lower than the polarity of the polar group generated by the dissociation of the acid-dissociable group. Is dissociated, a polar group having a higher polarity than the acid-dissociable group is generated, and the polarity increases. As a result, the polarity of the entire component (A1) increases. As the polarity increases, the solubility in the developer relatively changes, and when the developer is an organic developer, the solubility decreases.

The acid dissociable group is not particularly limited, and those that have been proposed as the acid dissociable group of the base resin for a chemically amplified resist can be used.
Among the polar groups, examples of the acid dissociable group that protects a carboxy group or a hydroxyl group include, for example, an acid dissociable group represented by the following general formula (a1-r-1) (hereinafter, for convenience, an “acetal-type acid dissociable group”). Group ").

［式中、Ｒａ’^１、Ｒａ’^２は水素原子またはアルキル基、Ｒａ’^３は炭化水素基、Ｒａ’^３は、Ｒａ’^１、Ｒａ’^２のいずれかと結合して環を形成してもよい。］

[Wherein Ra ′ ¹ and Ra ′ ² are a hydrogen atom or an alkyl group, Ra ′ ³ is a hydrocarbon group, and Ra ′ ³ is bonded to any of Ra ′ ¹ and Ra ′ ² to form a ring. Good. ]

In the formula (a1-r-1), as the alkyl group of Ra ′ ¹ and Ra ′ ² , in the description of the α-substituted acrylate ester, the alkyl group is mentioned as a substituent that may be bonded to the carbon atom at the α-position. The same as the alkyl group can be mentioned, a methyl group or an ethyl group is preferable, and a methyl group is most preferable.

As the hydrocarbon group for Ra ′ ³ , an alkyl group having 1 to 20 carbon atoms is preferable, and an alkyl group having 1 to 10 carbon atoms is more preferable; a linear or branched alkyl group is preferable. , Methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, 1,1-dimethylethyl, 1,1-diethylpropyl And a 2,2-dimethylpropyl group and a 2,2-dimethylbutyl group.

When Ra ′ ³ is a cyclic hydrocarbon group, it may be aliphatic or aromatic, 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. As the polycyclic alicyclic hydrocarbon group, a group obtained by removing one hydrogen atom from a polycycloalkane is preferable. As the polycycloalkane, one having 7 to 12 carbon atoms is preferable. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

When it is an aromatic hydrocarbon group, specific examples of the aromatic ring contained therein include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; and carbon atoms constituting the aromatic hydrocarbon ring. An aromatic heterocyclic ring partially substituted with a hetero atom; Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, a nitrogen atom and the like.
Specific examples of the aromatic hydrocarbon group include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring (aryl group); a group in which one hydrogen atom in the aryl group has been substituted with an alkylene group (for example, Benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, arylalkyl group such as 2-naphthylethyl group); The carbon number of the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

When Ra ′ ³ is bonded to any of Ra ′ ¹ and Ra ′ ² to form a ring, the cyclic group is preferably a 4- to 7-membered ring, more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  Among the polar groups, examples of the acid dissociable group that protects a carboxy group include an acid dissociable group represented by the following general formula (a1-r-2) (the following formula (a1-r-2) Of the acid dissociable groups represented by ()), those constituted by an alkyl group may be hereinafter referred to as “tertiary alkyl ester type acid dissociable groups” for convenience).

［式中、Ｒａ’^４〜Ｒａ’^６は炭化水素基であり、Ｒａ’^５、Ｒａ’^６は互いに結合して環を形成してもよい。］

[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. ]

Examples of the hydrocarbon group of Ra ′ ^{4 to} Ra ′ ⁶ are the same as those of the above-mentioned Ra ′ ³ . Ra ′ ⁴ is preferably an alkyl group having 1 to 5 carbon atoms. When Ra ′ ⁵ and Ra ′ ⁶ are bonded to each other to form a ring, a group represented by the following general formula (a1-r2-1) is exemplified.
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 general formula (a1-r2-2) may be mentioned.

［式中、Ｒａ’^１０は炭素数１〜１０のアルキル基、Ｒａ’^１１はＲａ’^１０が結合した炭素原子と共に脂肪族環式基を形成する基、Ｒａ’^１２〜Ｒａ’^１４は、それぞれ独立に炭化水素基を示す。］

[Wherein, Ra ′ ¹⁰ is an alkyl group having 1 to ¹⁰ carbon atoms, Ra ′ ¹¹ is a group which forms an aliphatic cyclic group together with the carbon atom to which Ra ′ ¹⁰ is bonded, Ra ′ ^{12 to} Ra ′ ¹⁴ are respectively Independently represents a hydrocarbon group. ]

In the formula (a1-r2-1), the alkyl group of the alkyl group of Ra ′ ¹⁰ having 1 to ¹⁰ carbon atoms is the linear or branched alkyl group of Ra ′ ³ in the formula (a1-r-1). The groups mentioned as above are preferred. In the formula (a1-r2-1), the aliphatic cyclic group represented by Ra ′ ¹¹ is preferably the group exemplified as the cyclic alkyl group of Ra ′ ³ in the formula (a1-r-1).

In the formula (a1-r2-2), Ra ′ ¹² and Ra ′ ¹⁴ are preferably each independently an alkyl group having 1 to 10 carbon atoms, and the alkyl group is represented by Ra in the formula (a1-r-1). 'The group mentioned as the linear or branched alkyl group of ³ is more preferable, a linear alkyl group having 1 to 5 carbon atoms is more preferable, and a methyl group or an ethyl group is particularly preferable. .
In the formula (a1-r2-2), Ra ′ ¹³ is a linear, branched or cyclic alkyl group exemplified as the hydrocarbon group of Ra ′ ³ in the formula (a1-r-1). Is preferred. Among these, the groups exemplified as the cyclic alkyl group of Ra ′ ³ are more preferable.

  Specific examples of the formula (a1-r2-1) are shown below. In the following formula, “*” indicates a bond.

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

  Among the polar groups, examples of the acid dissociable group that protects a hydroxyl group include, for example, an acid dissociable group represented by the following general formula (a1-r-3) (hereinafter referred to as “tertiary alkyloxycarbonyl acid for convenience”). A "dissociable group").

［式中、Ｒａ’^７〜Ｒａ’^９はアルキル基を示す。］

[Wherein, Ra ′ ^{7 to} Ra ′ ⁹ represent an alkyl group. ]

In the formula (a1-r-3), Ra ′ ^{7 to} Ra ′ ⁹ are preferably an alkyl group having 1 to 5 carbon atoms, more preferably 1 to 3.
Further, the total carbon number of each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

  The structural unit (a1) is a structural unit derived from an acrylate ester in which a hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and is an acid whose polarity is increased by the action of an acid. A structural unit containing a decomposable group; a structural unit in which at least a part of hydrogen atoms in a hydroxyl group of a structural unit derived from hydroxystyrene or a hydroxystyrene derivative is protected by a substituent containing the acid-decomposable group; Structural units in which at least a part of the hydrogen atoms in -C (= O) -OH of the structural unit derived from a vinylbenzoic acid derivative are protected by a substituent containing the acid-decomposable group are exemplified.

As the structural unit (a1), among the above, a structural unit derived from an acrylate ester in which a hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent is preferable.
As the structural unit (a1), a structural unit represented by the following general formula (a1-1) or (a1-2) is preferable.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基である。Ｖａ^１はエーテル結合、ウレタン結合、又はアミド結合を有していてもよい２価の炭化水素基であり、ｎ_ａ１は０〜２であり、
Ｒａ^１は上記式（ａ１−ｒ−１）〜（ａ１−ｒ−２）で表される酸解離性基である。Ｗａ^１
はｎ_ａ２＋１価の炭化水素基であり、ｎ_ａ２は１〜３であり、Ｒａ^２は上記式（ａ１−ｒ−１）または（ａ１−ｒ−３）で表される酸解離性基である。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Va ¹ is a divalent hydrocarbon group which may have an ether bond, a urethane bond, or an amide bond, na ₁ is 0 to 2,
Ra ¹ is an acid dissociable group represented by the above formulas (a1-r-1) to (a1-r-2). Wa ¹
Is a _n a2 +1 monovalent hydrocarbon _{group, n a2} is 1 to 3, Ra ² is an acid-dissociable group represented by the formula (a1-r-1) or (a1-r-3) is there. ]

In the general formula (a1-1), the alkyl group having 1 to 5 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, Examples include a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which part or all of the hydrogen atoms of the aforementioned alkyl group having 1 to 5 carbon atoms have been 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.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms, and most preferably a hydrogen atom or a methyl group in terms of industrial availability.
The hydrocarbon group of Va ¹ may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group as a divalent hydrocarbon group in Va ¹ may be saturated or unsaturated, and is usually preferably saturated.
More specific examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group and an aliphatic hydrocarbon group having a ring in the structure.
Va ¹ includes those in which the above divalent hydrocarbon group is bonded via 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, more preferably 1 to 4, and most preferably 1 to 3.
As the linear aliphatic hydrocarbon group, preferably a linear alkylene group, and specific examples include a methylene group _[-CH 2 -], an ethylene group _{[- (CH 2) 2 -} ], trimethylene [ _{- (CH 2) 3 -]} , a tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
As the branched aliphatic hydrocarbon group, preferably a branched chain alkylene group, _{specifically, -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 - ; alkylethylene groups such as - _{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) 2} -CH ₂ - alkyl groups such _{as; -CH (CH 3) CH 2} CH 2 -, - CH 2 CH (CH 3) CH 2 - alkyl trimethylene groups such as; -CH _(CH 3) _{CH 2 CH 2 CH 2 -,} - CH 2 CH (CH 3) CH 2 CH 2 - And the like alkyl alkylene group such as an alkyl tetramethylene group of. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable.

Examples of the aliphatic hydrocarbon group having a ring in the structure include an alicyclic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) and a linear or branched alicyclic hydrocarbon group. Examples thereof include a group bonded to the terminal of a chain aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include the same as described 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. As the polycyclic alicyclic hydrocarbon group, a group obtained by removing two hydrogen atoms from a polycycloalkane is preferable, and the polycycloalkane is preferably a group having 7 to 12 carbon atoms. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring.
The aromatic hydrocarbon group as a divalent hydrocarbon group in Va ¹ preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, still more preferably 5 to 20 carbon atoms, and 6 to 6 carbon atoms. 15 is particularly preferred, and 6 to 10 is most preferred. However, the number of carbon atoms does not include the number of carbon atoms 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 heterocyclic ring substituted with an atom; Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, a nitrogen atom and the like.
Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (arylene group); a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring (aryl group) ) Is a group in which one of the hydrogen atoms is substituted with an alkylene group (for example, arylalkyl such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl) A group in which one hydrogen atom has been further removed from an aryl group in the group); The carbon number of the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

In the formula (a1-2), n _{a2 +1} monovalent hydrocarbon group for Wa ¹ may be an aliphatic hydrocarbon group may be an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity, and may be saturated or unsaturated, and is usually preferably saturated. As the aliphatic hydrocarbon group, a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, or a linear or branched aliphatic hydrocarbon group It includes a group formed by combining an aliphatic hydrocarbon group in the structure containing a ring, and specific examples thereof include the same groups as Va ¹ of the aforementioned formula (a1-1).
The _na2 + 1 valence is preferably 2-4, more preferably 2 or 3.

  As the formula (a1-2), a structural unit represented by the following general formula (a1-2-01) is particularly preferable.

In the formula (a1-2-01), Ra ² is an acid dissociable group represented by the above formula (a1-r-1) or (a1-r-3). _na2 is an integer of 1 to 3, preferably 1 or 2, and more preferably 1. c is an integer of 0 to 3, preferably 0 or 1, and more preferably 1. R is the same as above.
Specific examples of the above formulas (a1-1) and (a1-2) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

  The proportion of the structural unit (a1) in the component (A) is preferably from 20 to 80 mol%, more preferably from 20 to 75 mol%, and still more preferably from 25 to 70 mol%, based on all the structural units constituting the component (A). Is more preferred. By setting the lower limit or more, the lithography characteristics such as sensitivity, resolution, and LWR are also improved. Further, by setting the content to be equal to or less than the upper limit value, it is possible to balance with other constituent units.

(Structural unit (a2))
The structural unit (a2) is a structural unit containing a lactone-containing cyclic group or a carbonate-containing cyclic group.
The lactone-containing cyclic group or carbonate-containing cyclic group of the structural unit (a2) is effective for enhancing the adhesion of the resist film to the substrate when the component (A1) is used for forming the resist film. is there.
In the present invention, the component (A1) preferably has a structural unit (a2).
When the structural unit (a1) has a lactone-containing cyclic group, a —SO ₂ -containing cyclic group, or a carbonate-containing cyclic group in its structure, the structural unit also corresponds to the structural unit (a2). However, such a structural unit corresponds to the structural unit (a1) and does not correspond to the structural unit (a2).

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

［式中、Ｒは水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基であり、Ｙａ^２１は単結合または２価の連結基であり、Ｌａ^２１は−Ｏ−、−ＣＯＯ−、−ＣＯＮ（Ｒ’）−、−ＯＣＯ−、−ＣＯＮＨＣＯ−又は−ＣＯＮＨＣＳ−であり、Ｒ’は水素原子またはメチル基を示す。ただしＬａ^２１が−Ｏ−の場合、Ｙａ^２１は−ＣＯ−にはならない。Ｒａ^２１はラクトン含有環式基、−ＳＯ_２−含有環式基又はカーボネート含有環式基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, Ya ²¹ is a single bond or a divalent linking group, and La ²¹ is -O —, —COO—, —CON (R ′) —, —OCO—, —CONHCO— or —CONHCS—, wherein 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 lactone-containing cyclic group, a —SO ₂ —-containing cyclic group or a carbonate-containing cyclic group. ]

The divalent linking group for Ya ²¹ is not particularly limited, but preferred examples thereof include a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom.

(A divalent hydrocarbon group which may have a substituent)
The hydrocarbon group as a divalent linking group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.
Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group having a ring in the structure, and the like. The groups exemplified for Va ¹ in 1) can be mentioned.

  The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and a carbonyl group substituted with a fluorine atom.

As the aliphatic hydrocarbon group containing a ring in the structure, a cyclic aliphatic hydrocarbon group which may contain a substituent containing a hetero atom in the ring structure (two hydrogen atoms are removed from an aliphatic hydrocarbon ring) A) a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, or a group in which the cyclic aliphatic hydrocarbon group is linear or branched. And a group interposed in the middle of the group hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include the same as described above.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
Specific examples of the cyclic aliphatic hydrocarbon group include the groups exemplified as Va ¹ in the above formula (a1-1).
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
As the alkoxy group as the substituent, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group are preferable. And ethoxy groups are most preferred.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the aforementioned alkyl group have been substituted with the aforementioned halogen atoms.
In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a hetero atom. As the substituent containing a hetero atom, -O-, -C (= O) -O-, -S-, -S (= O) _2- , and -S (= O) _2- O- are preferable.

Specific examples of the aromatic hydrocarbon group as the divalent hydrocarbon group include the groups exemplified by Va ¹ in the above formula (a1-1).
In the aromatic hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group, halogen atom and halogenated alkyl group as the substituent include those exemplified as the substituent for substituting a hydrogen atom of the cyclic aliphatic hydrocarbon group.

(Divalent linking group containing hetero atom)
The hetero atom in the divalent linking group containing a hetero atom is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.

When Ya ²¹ is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C (= O) -O-, -C (= O)-, and -OC. (= O) -O-, -C (= O) -NH-, -NH-, -NH-C (= NH)-(H may be substituted with a substituent such as an alkyl group or an acyl group. _{.), - S -, -} S (= O) 2 -, - S (= O) 2 -O-, the formula ^{-Y 21 -O-Y 22 -,} - Y 21 -O -, - Y 21 - C (= O) -O -, - C (= O) -O - Y 21, [Y 21 -C (= O) -O] m '-Y 22 - or ^-Y 21 -O-C (= O) -Y 22 ^- group [wherein represented by, Y ²¹ and Y ²² are each independently may be substituted divalent hydrocarbon group, O is an oxygen atom, m ′ is an integer of 0 to 3. And the like.
When the divalent linking group containing a hetero atom is -C (= O) -NH-, -NH-, -NH-C (= NH)-, H is a substituent such as an alkyl group or acyl. It may be substituted. The substituent (such as an alkyl group or an acyl group) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.
Formula ^{-Y 21 -O-Y 22 -,} - Y 21 -O -, - Y 21 -C (= O) -O -, - C (= O) -O-Y 21, - [Y 21 -C ( _{= O) -O] m '-Y} 22 - or ^{-Y 21 -O-C (= O} ) -Y 22 - ^{in, Y 21} and ^{Y 22} each independently have a substituent A good divalent hydrocarbon group. Examples of the divalent hydrocarbon group include those similar to the “divalent hydrocarbon group which may have a substituent” described in the description of the divalent linking group.
As Y ²¹ , a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 1 to 5 carbon atoms is further preferable, and a methylene group or an ethylene group is particularly preferable. preferable.
As Y ²² , a linear or branched aliphatic hydrocarbon group is preferable, and a methylene group, an ethylene group, or an alkylmethylene group is more preferable. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
Formula ^{- [Y 21 -C (= O} ) -O] m '-Y 22 - In the group represented by, m' is an integer of 0 to 3, preferably an integer of 0 to 2, 0 Alternatively, 1 is more preferable, and 1 is particularly preferable. In other words, the formula ^- Examples of the group represented by the formula ^{-Y 21 -C (= O) -O} -Y 22 - - [Y 21 -C (= O) -O] m '-Y 22 represented by Groups are particularly preferred. Among them, the formula _{- (CH 2) a '-C} (= O) -O- (CH 2) b' - a group represented by are preferred. In the formula, a ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, still more preferably 1 or 2, and most preferably 1. b ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, still more preferably 1 or 2, and most preferably 1.

In the present invention, Ya ²¹ is a single bond, an ester bond [—C (＝ O) —O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof. Preferably, there is.

“Lactone-containing cyclic group” refers to a cyclic group containing a ring (lactone ring) containing —OC (＝ O) — in the ring skeleton. The lactone ring is counted as the first ring. When only the lactone ring is used, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of its structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.
The lactone-containing cyclic group as the cyclic hydrocarbon group for R ¹ is not particularly limited, and any one can be used. Specific examples include groups represented by the following general formulas (a2-r-1) to (a2-r-7). Hereinafter, “*” represents a bond.

［式中、Ｒａ’^２１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり；Ｒ”は水素原子またはアルキル基であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｎ’は０〜２の整数であり、ｍ’は０または１である。］

[Wherein, Ra ′ ²¹ is 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 having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, and n 'is 0 to 2 And m ′ is 0 or 1. ]

In the general formulas (a2-r-1) to (a2-r-7), A ″ is a group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—). As the alkylene group having 1 to 5 carbon atoms in A ″, a linear or branched alkylene group is preferable, and a methylene group, an ethylene group, an n-propylene group, Isopropylene groups and the like. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal or the carbon atom of the alkylene group, 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 independently an alkyl group or an alkoxy group. Group, a halogen atom, a halogenated alkyl group, -COOR ", -OC (= O) R", a hydroxyalkyl group or a cyano group.
The alkyl group in ra ^'21, preferably an alkyl group having 1 to 5 carbon atoms.
The alkoxy group in 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 the alkyl group mentioned as the alkyl group in Ra ′ ²¹ and an oxygen atom (—O—) are linked.
Examples of the halogen atom in Ra ′ ²¹ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
'Examples of the halogenated alkyl group for ^21, the Ra' Ra part or all of the hydrogen atoms of the alkyl group in ²¹ can be mentioned it has been substituted with the aforementioned halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.

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

And _- "-SO 2 containing cyclic group", -SO 2 _- within the ring skeleton thereof shows a cyclic group containing a ring containing, in particular, -SO 2 _- sulfur atom (S) is in A cyclic group that forms part of the cyclic skeleton of the cyclic group. The ring containing -SO _{2-in the} ring skeleton is counted as the first ring, and if the ring alone is a monocyclic group, and if it has another ring structure, it is a polycyclic group regardless of the structure. Called. The —SO ₂ —-containing cyclic group may be monocyclic or polycyclic.
The —SO ₂ —-containing cyclic group as a cyclic hydrocarbon group for R ¹ is particularly a cyclic group containing —O—SO ₂ — in its ring skeleton, that is, —O—SO ₂ — in —O—SO ₂ —. It is preferred that -S- is a cyclic group containing a sultone ring that forms part of the ring skeleton. More specifically, examples of the —SO ₂ —-containing cyclic group include groups represented by the following general formulas (a5-r-1) to (a5-r-4).

［式中、Ｒａ’^５１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり；Ｒ”は水素原子またはアルキル基であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｎ’は０〜２の整数である。］

[Wherein, Ra ′ ⁵¹ is 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 having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, and n 'is 0 to 2 Is an integer. ]

In the general formulas (a5-r-1) to (a5-r-4), A ″ is the same as A ″ in the general formulas (a2-r-1) to (a2-r-7) described below. . Alkyl group in ra ^'51, an alkoxy group, a halogen atom, a halogenated alkyl group, -COOR ", - OC (= O) R", The hydroxyalkyl group, described below general formula (a2-r-1) ~ ( This is the same as Ra ′ ^{21 in} a2-r-7).

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

As the —SO ₂ —-containing cyclic group, a group represented by the general formula (a5-r-1) is preferable among the above, and the chemical formulas (r-sl-1-1) and (r-sl- 1-18), it is more preferable to use at least one selected from the group consisting of groups represented by any of (r-sl-3-1) and (r-sl-4-1), and the chemical formula The group represented by (r-sl-1-1) is most preferred.

The “carbonate-containing cyclic group” refers to a cyclic group containing a ring (carbonate ring) containing —OC (＝ O) —O— in its ring skeleton. The carbonate ring is counted as the first ring, and a carbonate ring alone is referred to as a monocyclic group, and a compound having another ring structure is referred to as a polycyclic group regardless of the structure. The carbonate-containing cyclic group may be a monocyclic group or a polycyclic group.
The carbonate ring-containing cyclic group as the cyclic hydrocarbon group for R ¹ is not particularly limited, and any one can be used. Specific examples include groups represented by the following general formulas (ax3-r-1) to (ax3-r-3).

［式中、Ｒａ’^ｘ３１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり；Ｒ”は水素原子またはアルキル基であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子でありｑ’は０または１である。］

^Wherein Ra ′ ^x31 is 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 having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, and q ′ is 0 or 1. is there. ]

A ″ in the general formulas (ax3-r-1) to (ax3-r-3) is the same as A ″ in the general formula (a2-r-1).
Alkyl group in ra ^'31, an alkoxy group, a halogen atom, a halogenated alkyl group, -COOR ", - OC (= O) R", The hydroxyalkyl group, each of the general formulas (a2-r-1) ~ ( The same as those described in the description of Ra ′ ^{21 in} a2-r-7) can be given.

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

  Among the above, as the lactone-containing cyclic group, a group represented by the general formula (a2-r-1) or (a2-r-2) is preferable, and the group represented by the chemical formula (r-lc-1-1) is preferable. Groups are more preferred.

The structural unit (a2) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a2), the proportion of the structural unit (a2) is preferably 1 to 80 mol% based on the total of all the structural units constituting the component (A1). The content is more preferably 5 to 70 mol%, further preferably 10 to 65 mol%, and particularly preferably 10 to 60 mol%. When the content is not less than the lower limit, the effect of containing the structural unit (a2) is sufficiently obtained. Has good lithography characteristics and pattern shape.

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

(Structural unit (a3))
The structural unit (a3) is a structural unit containing a polar group-containing aliphatic hydrocarbon group (however, excluding those corresponding to the structural units (a1) and (a2) described above).
It is considered that when the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) is increased, which contributes to improvement in resolution.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom, and a hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a cyclic aliphatic hydrocarbon group (cyclic group). The cyclic group may be a monocyclic group or a polycyclic group, and may be appropriately selected from, for example, those proposed for a resin for a resist composition for an ArF excimer laser. The cyclic group is preferably a polycyclic group, and more preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferred. Examples of the polycyclic group include groups obtained by removing two or more hydrogen atoms from bicycloalkane, tricycloalkane, tetracycloalkane, and the like. Specific examples include groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, a group obtained by removing two or more hydrogen atoms from adamantane, a group obtained by removing two or more hydrogen atoms from norbornane, and a group obtained by removing two or more hydrogen atoms from tetracyclododecane are given below. Industrially preferred.

The structural unit (a3) is not particularly limited as long as it contains a polar group-containing aliphatic hydrocarbon group, and any unit can be used.
The structural unit (a3) is a structural unit derived from an acrylate ester in which a hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and includes a polar group-containing aliphatic hydrocarbon group. Structural units are preferred.
As the structural unit (a3), when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a straight-chain or branched-chain hydrocarbon group having 1 to 10 carbon atoms, it is derived from hydroxyethyl ester of acrylic acid. When the hydrocarbon group is a polycyclic group, the structural unit represented by the following formula (a3-1), the structural unit represented by the following formula (a3-2), The structural unit represented by a3-3) is mentioned as a preferable example.

［式中、Ｒは前記と同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。］

[Wherein, R is the same as described 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, and 1 is an integer of 1 to 5 And s is an integer of 1 to 3. ]

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

In the formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5- or 6-position of the norbornyl group.
In the formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. It is preferable that a 2-norbornyl group or a 3-norbornyl group is bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded at the 5- or 6-position of the norbornyl group.

The structural unit (a3) contained in the component (A1) may be one type, or two or more types.
In the component (A1), the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on the total of all the structural units constituting the resin component (A1). Preferably, 5 to 25 mol% is more preferable.
When the proportion of the structural unit (a3) is equal to or higher than the lower limit, the effect of including the structural unit (a3) is sufficiently obtained. It will be easier.

(Structural unit (a4))
The structural unit (a4) is a structural unit containing an acid non-dissociable cyclic group. When the component (A1) has the structural unit (a4), the dry etching resistance of the formed resist pattern is improved. Further, the hydrophobicity of the component (A1) increases. The improvement in hydrophobicity is considered to contribute to the improvement of resolution, resist pattern shape, and the like, particularly in the case of organic solvent development.
The “acid-non-dissociable cyclic group” in the structural unit (a4) is, when an acid is generated from the component (B) described below by exposure, without dissociation even when the acid acts, in the structural unit as it is. The remaining cyclic groups.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing an acid non-dissociable aliphatic cyclic group is preferable. Examples of the cyclic group include those similar to those exemplified in the case of the structural unit (a1), such as an ArF excimer laser, a KrF excimer laser (preferably an ArF excimer laser), and the like. Many conventionally known ones can be used as the resin component of the resist composition.
In particular, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. 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 the structures of the following general formulas (a4-1) to (a4-7).

［式中、Ｒ^αは、水素原子、メチル基またはトリフルオロメチル基を示す。］

[In the formula, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group. ]

The structural unit (a4) contained in the component (A1) may be one type, or two or more types.
When the structural unit (a4) is contained in the component (A1), the proportion of the structural unit (a4) is preferably from 1 to 30 mol% based on the total of all the structural units constituting the component (A1), More preferably, it is 10 to 20 mol%.

  The component (A1) is preferably a copolymer having (a1) and (a2).

The component (A1) is obtained by polymerizing a monomer for deriving each structural unit by known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate. be able to.
Further, the component (A1), during the polymerization, by using a combination of chain transfer agent such as _{HS-CH 2 -CH 2 -CH 2} -C (CF 3) 2 -OH, end May be introduced with a —C (CF ₃ ) ₂ —OH group. As described above, a copolymer in which a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is introduced can reduce development defects and LER (line edge roughness: unevenness of line side walls). It is effective in reducing the amount of slag.

  In the present invention, the weight average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably from 1,000 to 50,000, more preferably from 1500 to 30,000, and 2,000 ~ 20,000 is most preferred. When it is less than the upper limit of this range, there is sufficient solubility in a resist solvent to be used as a resist, and when it is more than the lower limit of this range, dry etching resistance and cross-sectional shape of the resist pattern are good.

As the component (A1), one type may be used alone, or two or more types may be used in combination.
The proportion of the component (A1) in the base material component (A) is preferably at least 25% by mass, more preferably 50% by mass, still more preferably 75% by mass, based on the total mass of the base material component (A). % By mass. When the proportion is 25% by mass or more, the lithography characteristics are further improved.

In the present invention, as the component (A), one type may be used alone, or two or more types may be used in combination.
In the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

<Acid generator component; (B) component>
In the present invention, the resist composition may contain an acid generator component (B) that generates an acid upon exposure (hereinafter, referred to as a component (B)). The component (B) is not particularly limited, and those which have been proposed as an acid generator for a chemically amplified resist can be used.
Examples of such an acid generator include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based compounds such as bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There may be mentioned various types such as an acid generator, a nitrobenzylsulfonate-based acid generator, an iminosulfonate-based acid generator and a disulfone-based acid generator. Among them, it is preferable to use an onium salt-based acid generator.

  Examples of the onium salt-based acid generator include a compound represented by the following general formula (b-1) (hereinafter, also referred to as “component (b-1) component”) and a general formula (b-2) A compound (hereinafter also referred to as “component (b-2)”) or a compound represented by the general formula (b-3) (hereinafter also referred to as “component (b-3)”) can be used.

［式中、Ｒ^１０１、Ｒ^１０４〜Ｒ^１０８はそれぞれ独立に置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、または置換基を有していてもよい鎖状のアルケニル基である。Ｒ^１０４、Ｒ^１０５は、相互に結合して環を形成していてもよい。Ｒ^１０６〜Ｒ^１０７のいずれか２つは、相互に結合して環を形成していてもよい。Ｒ^１０２はフッ素原子または炭素数１〜５のフッ素化アルキル基である。Ｙ^１０１は単結合または酸素原子を含む２価の連結基である。Ｖ^１０１〜Ｖ^１０３はそれぞれ独立に単結合、アルキレン基、またはフッ素化アルキレン基である。Ｌ^１０１〜Ｌ^１０２はそれぞれ独立に単結合または酸素原子である。Ｌ^１０３〜Ｌ^１０５はそれぞれ独立に単結合、−ＣＯ−又は−ＳＯ_２−である。Ｍ’^ｍ＋はｍ価の有機カチオンである。］

[Wherein, R ¹⁰¹ and R ^{104 to} R ¹⁰⁸ each independently have a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a group which has a substituent. A chain alkenyl group which may be substituted. R ¹⁰⁴ and R ¹⁰⁵ may be mutually bonded to form a ring. Any two of R ^{106 to} R ¹⁰⁷ may be mutually bonded 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 each independently represent 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 ′ ^{m +} is an m-valent organic cation. ]

<< anion part >>
-Anion part of component (b-1) In the 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 linear alkenyl group which may have a substituent.

(Cyclic group which may have a substituent in R ¹⁰¹ )
The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group for R ¹⁰¹ is selected from the aromatic hydrocarbon rings listed for the divalent aromatic hydrocarbon group for Va ¹ in the formula (a1-1) or an aromatic compound containing two or more aromatic rings. An aryl group from which one hydrogen atom has been removed is mentioned, and a phenyl group and a naphthyl group are preferred.
The cyclic aliphatic hydrocarbon group for R ¹⁰¹ is a group obtained by removing one hydrogen atom from the monocycloalkane or polycycloalkane listed as the divalent aliphatic hydrocarbon group for Va ¹ in the formula (a1-1). And an adamantyl group and a norbornyl group are preferred.
Further, the cyclic hydrocarbon group for R ¹⁰¹ may contain a hetero atom such as a heterocyclic ring, and specifically, each of the general formulas (a2-r-1) to (a2-r-7) represents Lactone-containing cyclic groups represented by the formulas, -SO ₂ -containing cyclic groups represented by the above general formulas (a5-r-1) to (a5-r-4), and the following (r-hr-1) to Heterocyclic groups described in (r-hr-16) can be mentioned.

Examples of the substituent in the cyclic hydrocarbon group for R ¹⁰¹ include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group.
As the alkyl group as a substituent, an alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group are most preferable.
As the alkoxy group as a substituent, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group are more preferable. And ethoxy groups are most preferred.
Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as a substituent include an alkyl group having 1 to 5 carbon atoms, for example, a part or all of hydrogen atoms such as a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. Examples include a group substituted with a halogen atom.

(Chain alkyl group which may have a substituent in R ¹⁰¹ )
The chain alkyl group for R ¹⁰¹ may be 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, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henycosyl group, docosyl group and the like.
The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. 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, Examples thereof include a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

(A chain alkenyl group which may have a substituent in R ¹⁰¹ )
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, more preferably 2 to 4, and still more preferably 3 Is particularly preferred. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylpropenyl group and a 2-methylpropenyl group.
As the chain alkenyl group, among the above, a propenyl group is particularly preferable.

Examples of the substituent in the chain alkyl group or alkenyl group of R ¹⁰¹ include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and a cyclic group in R ¹⁰¹ described above. No.

Among them, R ¹⁰¹ is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, a phenyl group, a naphthyl group, a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and lactones represented by the above formulas (a2-r-1) to (a2-r-7) Preferred are a cyclic group containing, a —SO ₂ —-containing cyclic group represented by each of the general formulas (a5-r-1) to (a5-r-4), and the like.

In the 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. Examples of the atom other than the oxygen atom include a carbon atom, a hydrogen atom, a sulfur atom, and a nitrogen atom.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond: -O-), an ester bond (-C (= O) -O-), and an oxycarbonyl group (-OC (= O- )-), Non-hydrocarbons such as an amide bond (-C (= O) -NH-), a carbonyl group (-C (= O)-), and a carbonate bond (-OC (= O) -O-). System oxygen atom-containing linking group; a combination of the non-hydrocarbon oxygen atom-containing linking group with an alkylene group. A sulfonyl group (—SO ₂ —) may be further connected to the combination. Examples of the combination include linking groups represented by the following formulas (y-al-1) to (y-al-7).

［式中、Ｖ’^１０１は単結合または炭素数１〜５のアルキレン基であり、Ｖ’^１０２は炭素数１〜３０の２価の飽和炭化水素基である。］

[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 for V ′ ¹⁰² is preferably an alkylene group having 1 to 30 carbon atoms.

The alkylene group in V ′ ¹⁰¹ and V ′ ¹⁰² may be a linear alkylene group or a branched alkylene group, and is preferably a linear alkylene group.
As the alkylene group for V ^'101 and V' ^102, specifically, a 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 - ; alkylethylene groups such as 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 ) Alkyl ethylene group such as CH _2- ; trimethylene group (n-propylene group) [-CH ₂ CH ₂ CH _2- ]; -CH (CH ₃ ) CH ₂ CH _2- , -CH ₂ CH (CH ₃ ) CH ₂ - and the like alkyl trimethylene group; tetramethylene _{[-CH 2 CH 2 CH 2 CH} 2 -]; - CH (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; pentamethylene group _{[-CH 2 CH 2 CH 2 CH} 2 CH 2 -] , and the like.
Further, some methylene groups in the alkylene group in V ′ ¹⁰¹ or V ′ ¹⁰² may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is preferably a divalent group in which one more hydrogen atom has been removed from the cyclic aliphatic hydrocarbon group of Ra ′ ^{3 in} the formula (a1-r-1), and a cyclohexylene group , 1,5-adamantylene groups or 2,6-adamantylene groups are more preferred.

Y ¹⁰¹ is preferably a divalent linking group containing an ester bond or an ether bond, and is preferably a linking group represented by any of the above formulas (y-al-1) to (y-al-5).

In the 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 have been substituted with fluorine atoms. Among them, V ¹⁰¹ is preferably a single bond or a fluorinated alkylene group having 1 to 4 carbon atoms.

In the 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 anion portion of the component (b-1) include, for example,
When Y ¹⁰¹ is a single bond, a fluorinated alkylsulfonate anion such as a trifluoromethanesulfonate anion and a perfluorobutanesulfonate anion can be mentioned; when Y ¹⁰¹ is a divalent linking group containing an oxygen atom, Anions represented by any of -1) to (an-3).

［式中、Ｒ”^１０１は、置換基を有していてもよい脂肪族環式基、前記式（ｒ−ｈｒ−１）〜（ｒ−ｈｒ−６）でそれぞれ表される基、又は置換基を有していてもよい鎖状のアルキル基であり；Ｒ”^１０２は、置換基を有していてもよい脂肪族環式基、前記式（ａ２−ｒ−１）〜（ａ２−ｒ−７）でそれぞれ表されるラクトン含有環式基、又は前記一般式（ａ５−ｒ−１）〜（ａ５−ｒ−４）でそれぞれ表される−ＳＯ_２−含有環式基であり；Ｒ”^１０３は、置換基を有していてもよい芳香族環式基、置換基を有していてもよい脂肪族環式基、又は置換基を有していてもよい鎖状のアルケニル基であり；Ｖ”^１０１は、フッ素化アルキレン基であり；Ｌ”^１０１は、−Ｃ（＝Ｏ）−又は−ＳＯ_２−であり；ｖ”はそれぞれ独立に０〜３の整数であり、ｑ”はそれぞれ独立に１〜２０の整数であり、ｎ”は０または１である。］

[Wherein, R ″ ¹⁰¹ represents an aliphatic cyclic group which may have a substituent, a group represented by any of the above formulas (r-hr-1) to (r-hr-6), or a substituted group. R ″ ¹⁰² is an aliphatic cyclic group optionally having a substituent, and is an aliphatic cyclic group optionally having a substituent; lactone-containing cyclic group represented respectively by -7), or the formula (a5-r-1) ~ (a5-r-4) with -SO ₂ respectively represented - be-containing cyclic group; R And ¹⁰³ is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent. ^{There; V "101} is an fluorinated alkylene ^{group; L" 101} is, -C (= O) - or -SO ₂ - a and; v "0 to 3 are each independently Is an integer, q "are each independently an integer of 1 to 20, n" is 0 or 1. ]

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

The aromatic cyclic group which may have a substituent in R ″ ¹⁰³ is preferably the group exemplified as the aromatic hydrocarbon group in the cyclic hydrocarbon group in R ^{101. As} the substituent, , those similar to the substituent which may be substituted with aromatic hydrocarbon group for R ^101.

The chain alkyl group which may have a substituent in R " ¹⁰¹ is preferably the group exemplified as the chain alkyl group in R ^101. The group having a substituent in R" ¹⁰³ The preferable chain alkenyl group is preferably the group exemplified as the chain alkenyl group for R ¹⁰¹ . V ″ ¹⁰¹ is preferably a fluorinated alkylene group having 1 to 3 carbon atoms, particularly preferably —CF ₂ —, —CF ₂ CF ₂ —, —CHFCF ₂ —, or —CF (CF ₃ ) CF ₂ —. _{, -CH (CF 3) CF 2} - it is.

-Anion part of component (b-2) In formula (b-2), R ¹⁰⁴ and R ¹⁰⁵ each independently represent a cyclic group which may have a substituent, or a group which may have a substituent. It is a good chain alkyl group or a chain alkenyl group which may have a substituent, and examples thereof include the same ones as R ¹⁰¹ in formula (b-1). However, R ¹⁰⁴ and R ¹⁰⁵ may be mutually bonded to form a ring.
R ¹⁰⁴ and R ¹⁰⁵ are preferably a linear alkyl group which may have a substituent, and are a linear or branched alkyl group, or a linear or branched fluorinated alkyl group. Is more preferable.
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 number of carbon atoms in the chain alkyl group of R ¹⁰⁴ and R ¹⁰⁵ is preferably as small as possible within the range of the number of carbon atoms because the solubility in a resist solvent is good. Further, in the chain alkyl group of R ¹⁰⁴ and R ¹⁰⁵ , as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid increases, and the intensity of high-energy light or an electron beam of 200 nm or less increases. This is preferred because transparency is improved. The ratio 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 all hydrogen atoms are substituted with fluorine atoms. Perfluoroalkyl group.
In Formula (b-2), V ¹⁰² and V ¹⁰³ are each independently a single bond, an alkylene group, or a fluorinated alkylene group, and are the same as V ¹⁰¹ in Formula (b-1), respectively. No.
In the formula (b-2), L ^{101 to} L ¹⁰² are each independently a single bond or an oxygen atom.

-Anion part of component (b-3) In formula (b-3), R ^{106 to} R ¹⁰⁸ each independently represent a cyclic group which may have a substituent, or a group which may have a substituent. It is a good chain alkyl group or a chain alkenyl group which may have a substituent, and examples thereof include the same ones as R ¹⁰¹ in formula (b-1).
L ^{103 to} L ¹⁰⁵ are each independently a single bond, —CO— or —SO ₂ —.

｛Cation section｝
In the formulas (b-1), (b-2) and (b-3), M ′ ^{m +} is an organic cation having a valence of m, preferably a sulfonium cation or an iodonium cation, and is represented by the following general formula: Cations represented by (ca-1) to (ca-4) are particularly preferred.

［式中、Ｒ^２０１〜Ｒ^２０７、およびＲ^２１１〜Ｒ^２１２は、それぞれ独立に置換基を有していてもよいアリール基、アルキル基またはアルケニル基を表し、Ｒ^２０１〜Ｒ^２０３、Ｒ^２０６〜Ｒ^２０７、Ｒ^２１１〜Ｒ^２１２は、相互に結合して式中のイオウ原子と共に環を形成してもよい。Ｒ^２０８〜Ｒ^２０９はそれぞれ独立に水素原子または炭素数１〜５のアルキル基を表し、Ｒ^２１０は置換基を有していてもよいアリール基、アルキル基、アルケニル基、又は−ＳＯ_２−含有環式基であり、Ｌ^２０１は−Ｃ（＝Ｏ）−または−Ｃ（＝Ｏ）−Ｏ−を表し、Ｙ^２０１は、それぞれ独立に、アリーレン基、アルキレン基またはアルケニレン基を表し、ｘは１または２であり、Ｗ^２０１は（ｘ＋１）価の連結基を表す。］

[Wherein, 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 and R ²⁰⁶ to R ²⁰⁷ and R ^{211 to} R ²¹² may be mutually bonded to form a ring together 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, R 210} is an optionally substituted aryl group, an alkyl group, an alkenyl group, or -SO ₂ - containing A cyclic group, L ²⁰¹ represents —C (＝ O) — or —C (＝ O) —O—, Y ²⁰¹ each independently represents an arylene group, an alkylene group or an alkenylene group; 1 or 2, and W ²⁰¹ represents a (x + 1) -valent linking group. ]

Examples of the aryl group in R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² include an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group and a naphthyl group are preferable.
The alkyl group in R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² is a chain or cyclic alkyl group, and preferably has 1 to 30 carbon atoms.
The alkenyl group in R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² preferably has 2 to 10 carbon atoms.
Examples of the substituent that R ^{201 to} R ²⁰⁷ and R ^{210 to} R ²¹² may have include, for example, an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and an arylthio group. And groups represented by the following formulas (ca-r-1) to (ca-r-7).
The aryl group in the arylthio group as the substituent is the same as that described for R ¹⁰¹ , and specifically includes a phenylthio group and a biphenylthio group.

［式中、Ｒ’^２０１はそれぞれ独立に、水素原子、置換基を有していてもよい環式基、鎖状のアルキル基、または鎖状のアルケニル基である。］

[Wherein, R ′ ²⁰¹ is independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group, or a chain alkenyl group. ]

The cyclic group which may have a substituent, the chain-like alkyl group which may have a substituent, or the chain-like alkenyl group which may have a substituent of R ′ ²⁰¹ are as defined above. In addition to the same ones as R ¹⁰¹ in the formula (b-1), the above formula (C) may be a cyclic group which may have a substituent or a chain-like alkyl group which may have a substituent. The same as the acid dissociable group represented by a1-r-2) can also be used.

When R ^{201 to} R ²⁰³ , R ^{206 to} R ²⁰⁷ , and R ^{211 to} R ²¹² are mutually bonded to form a ring together with the sulfur atom in the formula, a hetero atom such as a sulfur atom, an oxygen atom, or a nitrogen atom; carbonyl _{group, -SO -, - SO 2 -} , - SO 3 -, - COO -, - CONH- , or -N _(R N) - (. the _{R N} is an alkyl group having 1 to 5 carbon atoms), etc. May be bonded via a functional group of As the ring formed, one ring containing a sulfur atom in the ring skeleton in the formula is preferably a 3- to 10-membered ring including a sulfur atom, and particularly preferably a 5- to 7-membered ring. preferable. 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, a thioxanthone ring, a thianthrene ring, a phenoxatiin ring, and a tetrahydro ring. A thiophenium ring, a tetrahydrothiopyranium ring and the like.

R ²⁰⁸ to R ²⁰⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,
A hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferable. When the alkyl group is formed, the alkyl group may be mutually bonded to form a ring.

R ²¹⁰ may have an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or a substituent. —SO ₂ —-containing cyclic group.
^Examples of the aryl group for R ²¹⁰ include 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 a chain or cyclic alkyl group, and preferably has 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 which may have a substituent in R ²¹⁰ , the same as the “—SO ₂ —containing cyclic group” of Ra ^{21 in} the above general formula (a2-1) is the same. And a group represented by the above general formula (a5-r-1) is preferable.

Y ²⁰¹ each independently represents an arylene group, an alkylene group or an alkenylene group.
As the arylene group for Y ^201, a group obtained by removing one hydrogen atom from the aryl group exemplified as the aromatic hydrocarbon group for R ¹⁰¹ in the formula (b-1) can be mentioned.
Examples of the alkylene group and alkenylene group for Y ²⁰¹ include the same as the aliphatic hydrocarbon group as the divalent hydrocarbon group for Va ¹ in the general formula (a1-1).

In the formula (ca-4), x is 1 or 2.
W ²⁰¹ is a (x + 1) -valent, that is, a divalent or trivalent linking group.
As the divalent linking group for W ^{201, a} divalent hydrocarbon group which may have a substituent is preferable, and examples thereof include the same hydrocarbon groups as Ya ²¹ in the general formula (a2-1). 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 a phenylene group and a naphthylene group, and a phenylene group is particularly preferred.
^Examples of the trivalent linking group in W ²⁰¹ include a group obtained by removing one hydrogen atom 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. No. As the trivalent linking group for W ²⁰¹ , a group in which two carbonyl groups are bonded to an arylene group is preferable.

  Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following formulas (ca-1-1) to (ca-1-63).

［式中、ｇ１、ｇ２、ｇ３は繰返し数を示し、ｇ１は１〜５の整数であり、ｇ２は０〜２０の整数であり、ｇ３は０〜２０の整数である。］

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

［式中、Ｒ”^２０１は水素原子又は置換基であって、置換基としては前記Ｒ^２０１〜Ｒ^２０７、およびＲ^２１０〜Ｒ^２１２が有していてもよい置換基として挙げたものと同様である。］

[In the formula, R ″ ²⁰¹ is a hydrogen atom or a substituent, and the substituents are the same as those described as the substituents that R ^{201 to} R ²⁰⁷ and R ^{210 to} R ²¹² may have. is there.]

  Specific examples of suitable cations represented by the formula (ca-3) include cations represented by the following formulas (ca-3-1) to (ca-3-6).

  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).

As the component (B), one of the above-described acid generators may be used alone, or two or more may be used in combination.
In the present invention, when the resist composition contains the component (B), the content of the component (B) is preferably 0.5 to 60 parts by mass, and more preferably 1 to 50 parts by mass based on 100 parts by mass of the component (A). Is more preferable, and 1 to 40 parts by mass is further preferable. By setting the content of the component (B) within the above range, pattern formation is sufficiently performed. Further, when each component of the resist composition is dissolved in an organic solvent, a uniform solution is obtained and storage stability is improved, which is preferable.

<Basic compound component; (D) component>
In the present invention, the resist composition further includes an acid diffusion controller component (hereinafter, also referred to as a “component (D)”) in addition to the component (A) or the components (A) and (B). May be contained.
The component (D) functions as a quencher (acid diffusion controller) for trapping an acid generated by exposure from the component (B) or the like.
The component (D) in the present invention may be a photo-disintegrable base (D1) (hereinafter, referred to as “component (D1)”) which decomposes upon exposure and loses acid diffusion controllability. It may be a nitrogen-containing organic compound (D2) not applicable (hereinafter, referred to as “component (D2)”).

[(D1) component]
By forming the resist composition containing the component (D1), the contrast between the exposed part and the non-exposed part can be improved when forming a resist pattern.
The component (D1) is not particularly limited as long as it is decomposed by exposure and loses the acid diffusion controllability, and is a compound represented by the following general formula (d1-1) (hereinafter referred to as “(d1-1) component”). ), A compound represented by the following general formula (d1-2) (hereinafter, referred to as “(d1-2) component”) and a compound represented by the following general formula (d1-3) (hereinafter, “(d1- One or more compounds selected from the group consisting of 3) components) are preferred.
The components (d1-1) to (d1-3) decompose in the exposed portion and lose the acid diffusion controllability (basicity), and thus do not act as a quencher in the unexposed portion.

［式中、Ｒｄ^１〜Ｒｄ^４は置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、または置換基を有していてもよい鎖状のアルケニル基である。ただし、式（ｄ１−２）中のＲｄ^２における、Ｓ原子に隣接する炭素原子にはフッ素原子は結合していないものとする。Ｙｄ^１は単結合、または２価の連結基である。Ｍ^ｍ＋はそれぞれ独立にｍ価の有機カチオンである。］

[Wherein, Rd ^{1 to} Rd ⁴ are a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain which may have a substituent. Alkenyl group. However, in Rd ² in the formula (d1-2), the carbon atom adjacent to the S atom and which has no fluorine atom bonded thereto. Yd ¹ is a single bond or a divalent linking group. M ^{m +} is each independently an m-valent organic cation. ]

{(D1-1) component}
-Anion part In the formula (d1-1), Rd ¹ has a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a group which has a substituent. And a similar chain alkenyl group, and examples thereof are the same as those for R ¹⁰¹ .
Among them, Rd ¹ may have an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or may have a substituent. A chain hydrocarbon group is preferred. As a substituent which these groups may have, a hydroxyl group, a fluorine atom or a fluorinated alkyl group is preferable.
The aromatic hydrocarbon group is more preferably a phenyl group or a naphthyl group.
The aliphatic cyclic group is more preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
As the chain hydrocarbon group, a chain alkyl group is preferable. The chain alkyl group preferably has 1 to 10 carbon atoms, specifically, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl Linear alkyl groups such as a group and a decyl group; 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group , 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl and the like.

When the chain alkyl group is a fluorinated alkyl group having a fluorine atom or a fluorinated alkyl group as a substituent, the fluorinated alkyl group preferably has 1 to 11 carbon atoms, more preferably 1 to 8 carbon atoms, The fluorinated alkyl group, which is more preferably 4 to 4, may contain an atom other than a fluorine atom. Examples of the atom other than the fluorine atom include an oxygen atom, a carbon atom, a hydrogen atom, a sulfur atom, and a nitrogen atom.
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 It is preferably a fluorinated alkyl group (a linear perfluoroalkyl group) in which all are substituted with fluorine atoms.

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

-Cation part In formula (d1-1), M ^{m +} is an organic cation having a valence of m.
The organic cation of M ^{m +} is not particularly limited, and examples thereof include the same cations as those represented by the general formulas (ca-1) to (ca-4). Cations represented by 1) to (ca-1-63) are preferred.
As the component (d1-1), one type may be used alone, or two or more types may be used in combination.

{(D1-2) component}
· During anion formula (d1-2), Rd ² is has an optionally substituted cyclic group which may have a substituent chain alkyl group or a substituted group, A chain alkenyl group which may be the same as those described for R ¹⁰¹ .
However, a fluorine atom is not bonded to a carbon atom adjacent to the S atom in Rd ² (not substituted with fluorine). Thereby, the anion of the component (d1-2) becomes an appropriate weak acid anion, and the quenching ability of the component (D) is improved.
Rd ² is preferably an aliphatic cyclic group which may have a substituent, and is a group obtained by removing one or more hydrogen atoms from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like. (May have a substituent); more preferably a group obtained by removing one or more hydrogen atoms from camphor or the like.
The hydrocarbon group for Rd ² may have a substituent, and the substituent may be a hydrocarbon group (aromatic hydrocarbon group, aliphatic hydrocarbon group) for Rd ¹ in the formula (d1-1). And the same as the substituents which may be possessed.

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

Cation moiety In the formula (d1-2), M ^{m +} is an organic cation having a valence of ^m, and is the same as M ^{m +} in the formula (d1-1).
As the component (d1-2), one type may be used alone, or two or more types may be used in combination.

{(D1-3) component}
During Anion formula (d1-3), Rd ³ is have an optionally substituted cyclic group which may have a substituent chain alkyl group or a substituted group, A alkenyl group which may be the same as R ^101, and is preferably a cyclic group containing a fluorine atom, a chain alkyl group, or a chain alkenyl group. Among them, a fluorinated alkyl group is preferable, and the same as the fluorinated alkyl group for Rd ¹ is more preferable.

In the formula (d1-3), Rd ⁴ may have a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a substituent. It is a chain alkenyl group, and examples thereof are the same as those of R ¹⁰¹ .
Among them, an alkyl group, an alkoxy group, an alkenyl group, and a cyclic group which may have a substituent are preferable.
The alkyl group for Rd ⁴ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group. Tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. A part of the hydrogen atoms of the alkyl group for 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, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, and an n- Butoxy group and tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferred.

The alkenyl group for Rd ⁴ is the same as the above-described R ^101, and is preferably a vinyl group, a propenyl group (allyl group), a 1-methylpropenyl group, or a 2-methylpropenyl group. These groups may further have, as a substituent, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms.

Examples of the cyclic group for Rd ⁴ include the same groups as those described above for R ¹⁰¹ , except for removing one or more hydrogen atoms from cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Preferred are alicyclic groups and aromatic groups such as a phenyl group and a naphthyl group. When Rd ⁴ is an alicyclic group, the resist composition is well dissolved in an organic solvent, so that lithography characteristics are improved. Further, when Rd ⁴ is an aromatic group, the resist composition has excellent light absorption efficiency and excellent sensitivity and lithography characteristics in lithography using EUV or the like as an exposure light source.

Wherein (d1-3), Yd ¹ represents a single bond or a divalent linking group.
The divalent linking group for Yd ¹ is not particularly limited, but may be a divalent hydrocarbon group (aliphatic hydrocarbon group or aromatic hydrocarbon group) which may have a substituent, or a group containing a hetero atom. And a valent linking group. These are the same as those described in the description of the divalent linking group of Ya ²¹ in the formula (a2-1).
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 linear or branched alkylene group, and further preferably a methylene group or an ethylene group.

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

Cation moiety In formula (d1-3), M ^{m +} is an organic cation having a valence of ^m, and is the same as M ^{m +} in formula (d1-1).
As the component (d1-3), one type may be used alone, or two or more types may be used in combination.

As the component (D1), any one of the above components (d1-1) to (d1-3) may be used alone, or two or more types may be used in combination.
The content of the component (D1) is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and more preferably 1 to 8 parts by mass, per 100 parts by mass of the component (A). More preferably, it is parts by mass.
When the content of the component (D1) is at least the preferred lower limit, particularly good lithography characteristics and a resist pattern shape can be obtained. On the other hand, when the value is not more than the upper limit, the sensitivity can be maintained satisfactorily and the throughput is also excellent.

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

  The content of the component (D1) is preferably from 0.5 to 10.0 parts by mass, more preferably from 0.5 to 8.0 parts by mass, per 100 parts by mass of the component (A). , 1.0 to 8.0 parts by mass. When it is at least the lower limit of the above range, particularly good lithography characteristics and resist pattern shape can be obtained. When it is at most the upper limit of the above range, the sensitivity can be maintained well and the throughput will be excellent.

((D2) component)
The component (D) may contain a nitrogen-containing organic compound component that does not correspond to the component (D1) (hereinafter, referred to as a component (D2)).
The component (D2) is not particularly limited as long as it functions as an acid diffusion controller and does not fall under the component (D1), and any known one may be used. Of these, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines, are preferred.
An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkylamine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or a hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of the alkylamine and the alkyl alcoholamine include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine and n-decylamine; diethylamine, di-n-propylamine, Dialkylamines such as -n-heptylamine, di-n-octylamine and dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine and tri-n-hexylamine Trialkylamines such as tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine and tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine; Li isopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among them, trialkylamines having 5 to 10 carbon atoms are more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

Examples of the cyclic amine include a heterocyclic compound containing a nitrogen atom as a hetero atom. The heterocyclic compound may be a monocyclic compound (aliphatic monocyclic amine) or a polycyclic compound (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, one having 6 to 10 carbon atoms is preferable, and specifically, 1,5-diazabicyclo [4.3.0] -5-nonene and 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane and the like.

  Other aliphatic amines include tris (2-methoxymethoxyethyl) amine, tris {2- (2-methoxyethoxy) ethyl} amine, tris {2- (2-methoxyethoxymethoxy) ethyl} amine, and tris {2 -(1-methoxyethoxy) ethyl} amine, tris {2- (1-ethoxyethoxy) ethyl} amine, tris {2- (1-ethoxypropoxy) ethyl} amine, tris [2- {2- (2-hydroxy) Ethoxy) ethoxy [ethyl] amine, triethanolamine triacetate and the like, with triethanolamine triacetate being preferred.

As the component (D2), an aromatic amine may be used.
Examples of the aromatic amine include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxy. Carbonylpyrrolidine and the like.

The component (D2) may be used alone or in combination of two or more.
The component (D2) is generally used in the range of 0.01 to 5.0 parts by mass based on 100 parts by mass of the component (A). By setting the content within the above range, the resist pattern shape, the stability with time of the leaving, and the like are improved.

As the component (D), one type may be used alone, or two or more types may be used in combination.
In the present invention, when the resist composition contains the component (D), the component (D) is preferably 0.1 to 15 parts by mass, and more preferably 0.3 to 15 parts by mass, per 100 parts by mass of the component (A). It is more preferably 12 parts by mass, and further preferably 0.5 to 12 parts by mass. When it is at least the lower limit of the above range, the lithography characteristics such as LWR will be more improved when the resist composition is used. Further, a better resist pattern shape can be obtained. When it is at most the upper limit of the above range, the sensitivity can be maintained well and the throughput will be excellent.

<Optional components>
[(E) component]
In the present invention, the resist composition contains, as an optional component, an organic carboxylic acid, and an oxo acid of phosphorus and a derivative thereof for the purpose of preventing deterioration in sensitivity, improving the resist pattern shape, and improving the stability over time. At least one compound (E) selected from the following group (hereinafter, referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of the oxo acid of phosphorus include phosphoric acid, phosphonic acid, and phosphinic acid, and among them, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include an ester obtained by replacing the hydrogen atom of the oxo acid with a hydrocarbon group. Examples of the hydrocarbon group include an alkyl group having 1 to 5 carbon atoms and a carbon number of 6 to 6 carbon atoms. And 15 aryl groups.
Examples of phosphoric acid derivatives include phosphate esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of the phosphonic acid derivative include phosphonic acid esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate.
Examples of the phosphinic acid derivative include phosphinic acid esters and phenylphosphinic acid.
As the component (E), one type may be used alone, or two or more types may be used in combination.
The component (E) is generally used in the range of 0.01 to 5.0 parts by mass based on 100 parts by mass of the component (A).

[(F) component]
In the present invention, the resist composition may contain a fluorine additive (hereinafter referred to as “component (F)”) in order to impart water repellency to the resist film.
As the component (F), for example, JP-A-2010-002870, JP-A-2010-032994, JP-A-2010-277043, JP-A-2011-13569, JP-A-2011-128226, The fluorinated polymer compounds described can be used.
More specifically, the component (F) includes a polymer having a structural unit (f1) represented by the following formula (f1-1). As the polymer, a polymer (homopolymer) composed of only the structural unit (f1) represented by the following formula (f1-1); a structural unit (f1) represented by the following formula (f1-1): A copolymer with the structural unit (a1); a structural unit (f1) represented by the following formula (f1-1), a structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1). Is preferable. Here, as the structural unit (a1) copolymerized with the structural unit (f1) represented by the following formula (f1-1), 1-ethyl-1-cyclooctyl (meth) acrylate or the above-mentioned formula (a1) 2-2-01) is preferable.

［式中、Ｒは前記同様であり、Ｒｆ^１０２およびＲｆ^１０３はそれぞれ独立して水素原子、ハロゲン原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基を表し、Ｒｆ^１０２およびＲｆ^１０３は同じであっても異なっていてもよい。ｎｆ^１は１〜５の整数であり、Ｒｆ^１０１はフッ素原子を含む有機基である。］

[Wherein, R is the same as described above, and Rf ¹⁰² and Rf ¹⁰³ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, Rf ¹⁰² and Rf ¹⁰³ may be the same or different. nf ¹ is an integer of ¹ to 5, and Rf ¹⁰¹ is an organic group containing a fluorine atom. ]

In the formula (f1-1), R is the same as described above. R is preferably a hydrogen atom or a methyl group.
In formula (f1-1), examples of the halogen atom for Rf ¹⁰² and Rf ¹⁰³ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. Examples of the alkyl group having 1 to 5 carbon atoms for Rf ¹⁰² and Rf ¹⁰³ are the same as the alkyl groups having 1 to 5 carbon atoms for R, and a methyl group or an ethyl group is preferable. As the halogenated alkyl group having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ , specifically, a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms is substituted with a halogen atom is mentioned. No. 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 more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group.
In the formula (f1-1), nf ¹ is an integer of ¹ to 5, preferably an integer of 1 to 3, and more preferably 1 or 2.

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 particularly preferably 1 to 10 carbon atoms.
In the hydrocarbon group containing a fluorine atom, 25% or more of the hydrogen atoms in the hydrocarbon group are preferably fluorinated, more preferably 50% or more are fluorinated, and 60% or more are fluorinated. Fluorination is particularly preferred because the hydrophobicity of the resist film at the time of immersion exposure increases.
Among ^these, as ^{Rf 101,} particularly preferably a fluorinated hydrocarbon group having 1 to 5 carbon atoms, a methyl _{group, -CH 2 -CF 3, -CH 2} -CF 2 -CF 3, -CH (CF 3) 2 _{, -CH} 2 _-CH 2 _-CF 3, and most preferably _{-CH 2 -CH 2 -CF 2 -CF 2} -CF 2 -CF 3.

The weight average molecular weight (Mw) of the component (F) (based on gel permeation chromatography in terms of polystyrene) is preferably from 1,000 to 50,000, more preferably from 5,000 to 40,000, and most preferably from 10,000 to 30,000. When it is less than the upper limit of this range, there is sufficient solubility in a resist solvent to be used as a resist, and when it is more than the lower limit of this range, dry etching resistance and cross-sectional shape of the resist pattern are good.
The dispersity (Mw / Mn) of the component (F) is preferably from 1.0 to 5.0, more preferably from 1.0 to 3.0, and most preferably from 1.2 to 2.5.

As the component (F), one type may be used alone, or two or more types may be used in combination.
The component (F) is generally used in a proportion of 0.5 to 10 parts by mass with respect to 100 parts by mass of the component (A).

  In the present invention, the resist composition may further contain an additive which is optionally miscible, for example, an additional resin for improving the performance of the resist film, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, and an antihalation agent. , Dyes and the like can be added and contained as appropriate.

[(S) component]
In the present invention, the resist composition can be produced by dissolving the materials in an organic solvent (hereinafter sometimes referred to as component (S)).
As the component (S), any component may be used as long as it can dissolve each component to be used to form a uniform solution, and any one of conventionally known solvents for chemically amplified resists may be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone, methyl-n-pentyl ketone (2-heptanone), and methyl isopentyl ketone; ethylene glycol, diethylene glycol, propylene glycol, diethylene glycol Polyhydric alcohols such as propylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate; compounds having the polyhydric alcohol or the compound having the ester bond Monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, and monophenyl ether Derivatives of polyhydric alcohols such as compounds having an ether bond such as propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferable; cyclic ethers such as dioxane; , Methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; esters; anisole, ethylbenzyl ether, cresylmethyl Ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene And dimethyl sulfoxide (DMSO).
These organic solvents may be used alone or as a mixed solvent of two or more.
Among them, PGMEA, PGME, γ-butyrolactone, and EL are preferable.
Further, a mixed solvent obtained by mixing PGMEA and a polar solvent is also preferable. The compounding ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, and is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL or cyclohexanone is blended as the polar solvent, the mass ratio of PGMEA: EL or cyclohexanone is preferably from 1: 9 to 9: 1, and more preferably from 2: 8 to 8: 2. . When PGME is blended 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 still more preferably 3: 7 to 7 :. 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL 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 use amount of the component (S) is not particularly limited, and is appropriately set at a concentration that can be applied to a substrate or the like according to the applied film thickness. Generally, the resist composition is used so that the solid content concentration thereof is in the range of 1 to 20% by mass, preferably 2 to 15% by mass.

In the method for forming a split pattern according to the present invention, a first resist pattern is formed in step A, and the solubility of the surface of the first resist pattern in a developing solution is changed in steps B to D. Thereafter, in step E, organic solvent development is performed to remove the organic solvent-soluble region of the first resist pattern, thereby forming a split pattern in which the first resist pattern is divided into lines, spaces, and lines (split). Is done.
In step E, the organic solvent-soluble region of the first resist pattern is removed by organic solvent development, that is, the portion indicated by 2b in FIG. 1D is removed. If the compound has sufficient solubility in a solvent, the portion indicated by 2b is easily removed (in other words, easily removed) in the developing step of step E, and is about several tens of nm (more specifically, (20 to 30 nm).
Therefore, the resist composition for forming the first resist pattern preferably has a high dissolution rate in an organic solvent.

When the dissolution rate is, for example, the dissolution rate in an organic solvent such as butyl acetate (film loss / immersion time), the maximum value of the dissolution rate (R _max , unit: nm / s) may be 5 nm / s or more. It is more preferably at least 10 nm / s. The minimum value of the dissolution rate ( _Rmin , unit: nm / s) is preferably 1 nm / s or less, more preferably 0.5 nm / s or less.

[Step B]
In step B, a solution containing an acid or a thermal acid generator is applied so as to cover the first resist pattern, thereby forming a first layer. In the step B, as shown in FIG. 1B, the first layer 3 is formed so as to cover the first resist pattern 2 formed in the step A.

(Solution containing acid or thermal acid generator)
In the present invention, a solution containing an acid or a thermal acid generator will be described. The solution containing an acid or thermal acid generator preferably comprises an acid or thermal acid generator, a polymer compound, and a solvent.
[Acid (acid component (T0))]
In the present invention, the “acid” itself has acidity and acts as a proton donor (hereinafter, may be described as “acid component (T0)”). Examples of such a (T0) component include nonionic acids that do not form a salt.
Examples of the (T0) component include fluorinated alkyl group-containing carboxylic acids, higher fatty acids, higher alkyl sulfonic acids, higher alkyl aryl sulfonic acids, and camphor sulfonic acid.

Examples of the fluorinated alkyl group-containing carboxylic acid include C ₁₀ F ₂₁ COOH.
Examples of the higher fatty acid include higher fatty acids having an alkyl group having 8 to 20 carbon atoms, and specific examples include dodecanoic acid, tetradecanoic acid, and stearic acid.
The alkyl group having 8 to 20 carbon atoms may be linear or branched, and a phenylene group or an oxygen atom may be interposed in the chain. Some of the atoms may be substituted with a hydroxyl group or a carboxy group.
Examples of the higher alkyl sulfonic acid include sulfonic acids having an alkyl group having an average carbon number of preferably 9 to 21, more preferably 12 to 18, and specific examples thereof include decanesulfonic acid, dodecanesulfonic acid, and tetradecanesulfonic acid. Pentadecanesulfonic acid, stearic sulfonic acid and the like.
Examples of the higher alkylarylsulfonic acid include alkylbenzenesulfonic acid and alkylnaphthalenesulfonic acid having an alkyl group having an average carbon number of preferably 6 to 18, more preferably 9 to 15, and specifically, dodecylbenzenesulfonic acid. Acid and decylnaphthalenesulfonic acid.

  Other acid components include alkyl diphenyl ether disulfonic acids having an alkyl group having an average carbon number of preferably 6 to 18, more preferably 9 to 15, and specific examples include dodecyl diphenyl ether disulfonic acid.

[Thermal acid generator (acid component (T1))]
The thermal acid generator (hereinafter sometimes referred to as “acid component (T1)”) is a component that generates an acid by heating. Examples of the thermal acid generator component that generates an acid upon heating include onium salt-based acid generators such as iodonium salts and sulfonium salts; oxime sulfonate-based acid generators; bisalkyl or bisarylsulfonyldiazomethanes; Various types are known, such as diazomethane-based acid generators such as sulfonyl) diazomethanes; nitrobenzylsulfonate-based acid generators; iminosulfonate-based acid generators; and disulfone-based acid generators. These acid generator components, also known as photoacid generators, also function as thermal acid generators. Accordingly, as the acid generator component that can be used in the present invention, any of those conventionally known as an acid generator for a chemically amplified resist composition can be used.
Among them, the acid component (T1) is preferably one represented by any of the following formulas (T1-1) to (T1-3).

［式中、Ｒｔ^１０１、Ｒｔ^１０４〜Ｒｔ^１０８はそれぞれ独立に置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、または置換基を有していてもよい鎖状のアルケニル基である。Ｒｔ^１０４、Ｒｔ^１０５は、相互に結合して環を形成していてもよい。Ｒｔ^１０６〜Ｒｔ^１０７のいずれか２つは、相互に結合して環を形成していてもよい。Ｒｔ^１０２はフッ素原子または炭素数１〜５のフッ素化アルキル基である。Ｙｔ^１０１は単結合または酸素原子を含む２価の連結基である。Ｖｔ^１０１〜Ｖｔ^１０３はそれぞれ独立に単結合、アルキレン基、またはフッ素化アルキレン基である。Ｌｔ^１０１〜Ｌｔ^１０２はそれぞれ独立に単結合または酸素原子である。Ｌｔ^１０３〜Ｌｔ^１０５はそれぞれ独立に単結合、−ＣＯ−又は−ＳＯ_２−である。Ｒｔ^３０１〜Ｒｔ^３０４は、それぞれ独立に、水素原子又は炭素数１〜１２の直鎖状、分岐鎖状又は環状のフッ素化アルキル基である。Ｒｔ^３０１〜Ｒｔ^３０３は、相互に結合して式中の窒素原子と共に環を形成していてもよい。］

[Wherein, Rt ¹⁰¹ , Rt ^{104 to} Rt ¹⁰⁸ each independently have a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a substituent. A chain alkenyl group which may be substituted. Rt ¹⁰⁴ and Rt ¹⁰⁵ may be bonded to each other to form a ring. Any two of Rt ^{106 to} Rt ¹⁰⁷ may be mutually bonded to form a ring. Rt ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. Yt ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom. Vt ^{101 to} Vt ¹⁰³ are each independently a single bond, an alkylene group, or a fluorinated alkylene group. Lt ^{101 to} Lt ¹⁰² are each independently a single bond or an oxygen atom. Lt ^{103 to} Lt ¹⁰⁵ are each independently a single bond, —CO— or —SO ₂ —. Rt ^{301 to} Rt ³⁰⁴ are each independently a hydrogen atom or a linear, branched or cyclic fluorinated alkyl group having 1 to 12 carbon atoms. Rt ^{301 to} Rt ³⁰³ may combine with each other to form a ring together with the nitrogen atom in the formula. ]

<< anion part >>
-Anion part of component (T1-1) In formula (T1-1), Rt ¹⁰¹ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, Or a linear alkenyl group which may have a substituent.
In the formula (T1-1), the description of Rt ^{101 is the same} as the description of R ¹⁰¹ in the above formula (b-1).

In formula (T1-1), Yt ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom.
The description of Yt ¹⁰¹ in the formula (T1-1) is the same as the description of Y ¹⁰¹ in the above formula (b-1).

In the formula (T1-1), Vt ¹⁰¹ is a single bond, an alkylene group, or a fluorinated alkylene group. The alkylene group and the fluorinated alkylene group in Vt ¹⁰¹ preferably have 1 to 4 carbon atoms. As the fluorinated alkylene group for Vt ^101, some or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms in the vt ^101. Among them, Vt ¹⁰¹ is preferably a single bond or a fluorinated alkylene group having 1 to 4 carbon atoms.

Wherein ^{(T1-1), Rt 102} is a fluorine atom or a fluorinated alkyl group of 1 to 5 carbon atoms. Rt 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 anion part of (T1-1) component, for example, if Yt ¹⁰¹ is a single bond, include fluorinated alkyl sulfonate anions such as trifluoromethane sulfonate anion or perfluorobutane sulfonate anion; Yt ¹⁰¹ is In the case of a divalent linking group containing an oxygen atom, an anion represented by any of the above formulas (an-1) to (an-3) can be mentioned.

-Anion part of component (T1-2) In formula (T1-2), Rt ¹⁰⁴ and Rt ¹⁰⁵ each independently may have a cyclic group which may have a substituent, or may have a substituent. A good chain alkyl group or a good chain alkenyl group which may have a substituent, each of which is the same as Rt ¹⁰¹ in formula (T1-1). However, Rt ¹⁰⁴ and Rt ¹⁰⁵ may be bonded to each other to form a ring.
Rt ¹⁰⁴ and Rt ¹⁰⁵ are preferably a linear alkyl group which may have a substituent, and are a linear or branched alkyl group, or a linear or branched fluorinated alkyl group. Is more preferable.
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 number of carbon atoms in the chain alkyl group of Rt ¹⁰⁴ and Rt ¹⁰⁵ is, the better the solubility in a resist solvent is, for example, within the above-mentioned number of carbon atoms. Further, in the chain alkyl group of Rt ¹⁰⁴ and Rt ¹⁰⁵ , as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid increases, and the intensity of high-energy light or an electron beam of 200 nm or less increases. This is preferred because transparency is improved. The ratio 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 all hydrogen atoms are substituted with fluorine atoms. Perfluoroalkyl group.
In the formula (T1-2), Vt ¹⁰² and Vt ¹⁰³ each independently represent a single bond, an alkylene group, or a fluorinated alkylene group, each of which is the same as Vt ¹⁰¹ in the formula (T1-1). No.
In formula (T1-2), Lt ^{101 to} Lt ¹⁰² each independently represent a single bond or an oxygen atom.

During · (T1-3) component of Anion formula ^(T1-3), Rt 106 ~Rt ¹⁰⁸ are each independently optionally substituted cyclic group, which may have a substituent A good chain alkyl group or a good chain alkenyl group which may have a substituent, each of which is the same as Rt ¹⁰¹ in formula (T1-1).
Lt ^{103 to} Lt ¹⁰⁵ are each independently a single bond, —CO— or —SO ₂ —.

｛Cation section｝
In the cation moiety of the general formulas (T1-1) to (T1-3), Rt ^{301 to} Rt ³⁰⁴ each independently represent a hydrogen atom or a linear, branched or cyclic fluorinated group having 1 to 12 carbon atoms. It is an alkyl group. Rt ^{301 to} Rt ³⁰³ may combine with each other to form a ring together with the nitrogen atom in the formula. As the ring formed, one ring containing a nitrogen atom in the ring skeleton in the formula is preferably a 3- to 10-membered ring including a nitrogen atom, and particularly preferably a 5- to 7-membered ring. preferable. Specific examples of the ring formed include, for example, a pyridine ring. Hereinafter, preferred specific examples of the cation moiety of the general formulas (T1-1) to (T1-3) are listed.

  As a preferred acid component (T1), a compound represented by the above general formula (T1-1) is preferable, and as an anion part of the compound represented by the above general formula (T1-1), An anion moiety represented by an-1) is preferable.

In the solution containing an acid or a thermal acid generator, the above-mentioned acid component (T0) or (T1) may be used alone or in a combination of two or more.
In the present invention, the content of the acid component (T0) or (T1) in the solution containing the acid or the thermal acid generator is 0.1 to 5 parts by mass based on 100 parts by mass of the solution containing the acid or the thermal acid generator. Is preferably 0.15 to 3 parts by mass, more preferably 0.15 to 1.5 parts by mass.

[Polymer compound (Tp)]
In the present invention, a polymer compound that is preferably contained in a solution containing an acid or a thermal acid generator will be described. A polymer compound preferably contained in a solution containing an acid or a thermal acid generator may be referred to as a “polymer compound (Tp)”. The polymer compound (Tp) improves the coatability of a solution containing an acid or a thermal acid generator, and can be removed in the organic solvent development in step E described below, that is, a polymer compound soluble in an organic solvent. It is not particularly limited.
In the present invention, the polymer compound (Tp) preferably contains a structural unit having a hydrocarbon group which may have a substituent. Examples of the structural unit having a hydrocarbon group which may have a substituent include a structural unit represented by the following general formula (Tp) -1.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基であり、Ｒｔｐは置換基を有していてもよい炭化水素基である。ｎ_ｔｐは０又は１である。また、ｎ_ｔｐが０のとき、Ｒｔｐは水酸基であってもよい。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and Rtp is a hydrocarbon group which may have a substituent. n _tp is 0 or 1. _Also, when _{n tp} is 0, Rtp may be a hydroxyl group. ]

In the general formula (Tp) -1, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Similarly, in the formula (Tp) -1, R is preferably a hydrogen atom or a methyl group.
In formula (Tp) -1, Rtp is a hydrocarbon group which may have a substituent.

As the hydrocarbon group for Rtp, an alkyl group having 1 to 20 carbon atoms is preferable, and an alkyl group having 1 to 10 carbon atoms is more preferable; a linear or branched alkyl group is preferable. Group, ethyl group, propyl 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-dimethylpropyl group, 2,2-dimethylbutyl group and the like.
When Rtp 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. As the polycyclic alicyclic hydrocarbon group, a group obtained by removing one hydrogen atom from a polycycloalkane is preferable. As the polycycloalkane, one having 7 to 12 carbon atoms is preferable. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

When Rtp is an aromatic hydrocarbon group, specific examples of the aromatic ring contained therein include: an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; and carbon atoms constituting the aromatic hydrocarbon ring. An aromatic heterocycle in which a part of the atoms is substituted with a hetero atom; Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, a nitrogen atom and the like.
Specific examples of the aromatic hydrocarbon group include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring (aryl group); a group in which one hydrogen atom in the aryl group has been substituted with an alkylene group (for example, Benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, arylalkyl group such as 2-naphthylethyl group); The carbon number of the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

Rtp may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
As the alkoxy group as the substituent, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group are preferable. And ethoxy groups are most preferred.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the aforementioned alkyl group have been substituted with the aforementioned halogen atoms.
In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a hetero atom. As the substituent containing a hetero atom, -O-, -C (= O) -O-, -S-, -S (= O) _2- , and -S (= O) _2- O- are preferable.
_Also, when _{n tp} is 0, Rtp may be a hydroxyl group.

The structural unit represented by the general formula (Tp) -1 is a structural unit ((Tp) -1-1) containing a polar group-containing aliphatic hydrocarbon group having a polar group as a substituent, and is derived from hydroxystyrene. Structural unit ((Tp) -1-2), a structural unit derived from styrene ((Tp) -1-3), a structural unit containing a linear or cyclic aliphatic hydrocarbon group ((Tp) -1) -4), and a structural unit ((Tp) -1-5) derived from vinyl alcohol.
In the present invention, as the structural unit (Tp) -1-1, the structural unit (a3) containing the above-described polar group-containing aliphatic hydrocarbon group is preferable, and particularly, the general formula (a3-1) or (a3) is preferable. The structural unit represented by -3) is preferable.
Examples of the structural unit (Tp) -1-2 include a structural unit represented by the following general formula (Tp) -1-2-1. Examples of the structural unit (Tp) -1-3 include a structural unit represented by the following general formula (Tp) -1-3-1.

（式中、Ｒ^ｓｔは水素原子またはメチル基を表し、ｍ_０１は１〜３の整数を表す。）

(In the formula, R ^st represents a hydrogen atom or a methyl group, and m ₀₁ represents an integer of 1 to 3.)

（式中、Ｒ^ｓｔは水素原子又はメチル基を表し、Ｒ^０１は炭素数１〜５のアルキル基を表し、ｍ_０２は０または１〜３の整数を表す。）

(In the formula, R ^st represents a hydrogen atom or a methyl group, R ⁰¹ represents an alkyl group having 1 to 5 carbon atoms, and m ₀₂ represents 0 or an integer of 1 to 3.)

In the formula (Tp) -1-2-1, R ^st is a hydrogen atom or a methyl group, and is preferably a hydrogen atom.
m ₀₁ is an integer of 1 to 3. Of these, m ₀₁ is preferably 1.
The position of the hydroxyl group may be any of the o-position, the m-position, and the p-position. However, since it is easily available and inexpensive, those having m = 1 and having a hydroxyl group at the p-position are preferred. preferable. When m ₀₁ is 2 or 3, arbitrary substitution positions can be combined.

In the formula (Tp) -1-3-1, R ^st is a hydrogen atom or a methyl group, and is preferably a hydrogen atom.
R ⁰¹ is a linear or branched alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl. And a neopentyl group. Industrially, a methyl group or an ethyl group is preferred.

The above m ₀₂ is 0 or an integer of 1 to 3. Of these, m ₀₂ is preferably 0 or 1, and particularly preferably 0 industrially.
When m ₀₂ is 1, the substitution position of R ⁰¹ may be any of the o-position, m-position, and p-position. When m ₀₂ is 2 or 3, any substitution position Positions can be combined.

  As the structural unit (Tp) -1-4, a structural unit represented by any one of the general formulas (a4-1) to (a4-7) or the following general formula (Tp) -1-4-1 The structural unit represented is mentioned.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基であり、Ｒｔｐ^０４は、炭素数１〜１０の直鎖状のアルキル基である。］

In the formula, R represents a hydrogen atom, a halogenated alkyl group of 1 to 5 alkyl or C1-5 atoms, ^{Rtp 04} is a linear alkyl group having 1 to 10 carbon atoms. ]

  The polymer compound (Tp) preferably contained in the solution containing an acid or a thermal acid generator is represented by the structural unit represented by (Tp) -1-2 and the structural unit represented by (Tp) -1-3. A combination containing two or more types of the structural unit represented by (Tp) -1-1, a combination containing two or more types of the structural unit represented by the above (Tp) -1-4, polyvinyl Alcohols are preferred.

The solution containing an acid or a thermal acid generator may use the above-mentioned polymer compound (Tp) alone or in combination of two or more.
In the present invention, the content of the polymer compound (Tp) in the solution containing the acid or the thermal acid generator is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the solution containing the acid or the thermal acid generator. 0.2-5 mass parts is more preferable, and 0.3-3 mass parts is still more preferable.

〔solvent〕
In the present invention, a solvent preferably contained in a solution containing an acid or a thermal acid generator (hereinafter, sometimes referred to as “solvent (B)”) will be described. In step B, a solution containing an acid or a thermal acid generator is applied so as to cover the first resist pattern to form a first layer. Therefore, the solvent contained in the solution containing an acid or a thermal acid generator is preferably a solvent that does not dissolve the first resist pattern.
Specifically, it is preferable to employ water, an ether solvent or a linear monohydric alcohol having 1 to 10 carbon atoms.
An ether solvent is an organic solvent containing C—O—C in its structure. Examples thereof include diethyl ether, 1- (isopentyloxy) -3-methylbutane, diisopropyl ether, and tetrahydrofuran.
The alcohol solvent is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be linear, branched, or cyclic. Specifically, 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol, 4-hexanol Methylpentan-2-ol, 2-methylbutan-1-ol and the like can be mentioned. Among these, 4-methylpentan-2-ol or 2-methylbutan-1-ol is more preferred.

  The amount of the solvent (B) used is not particularly limited, and is appropriately set at a concentration that can be applied on the first resist pattern according to the applied film thickness. Generally, the solution containing the acid or the thermal acid generator is used so that the solid content concentration thereof is in the range of 0.1 to 10% by mass, preferably 1 to 5% by mass.

  The thickness of the first layer is not particularly limited as long as the first resist pattern is covered. For example, the pattern height of the first resist pattern is preferably 0.2 to 2.0 with respect to 1. , 0.3 to 1.8, more preferably 0.5 to 1.2.

[Step C]
Step C is a step of applying a solution comprising a solvent so as to cover the first layer.
As shown in FIG. 1C, a solution 4 composed of a solvent is applied so as to cover the first layer 3.
The solution composed of the solvent is applied mainly for the purpose of controlling the action of the acid contained in the first layer formed in the step B. The solution 4 composed of a solvent is applied so as to cover the first layer 3 and may be partially mixed with the upper part of the first layer.

The solvent (hereinafter sometimes referred to as “solvent (C)”) is not particularly limited as long as the action of the acid can be controlled.
As the solvent (C), in addition to the solvents similar to the solvent (B), those listed as the component (S) in the resist composition, or a mixed solvent thereof can be used.
Of these, a solvent that does not dissolve the first layer is preferable as the solvent (C), and thus a low-polarity solvent is preferably used.
Examples of the low-polarity solvent include an aliphatic hydrocarbon solvent having 4 to 12 carbon atoms such as butane, pentane, hexane, and octane; an aromatic hydrocarbon solvent such as toluene and xylene; and an alicyclic hydrocarbon solvent such as cyclohexane. Is mentioned.
Among them, diethyl ether, 1- (isopentyloxy) -3-methylbutane, diisopropyl ether, tetrahydrofuran, or a mixed solvent of 1- (isopentyloxy) -3-methylbutane and PGMEA is preferable.

In the present invention, the solvent solution preferably contains an acid diffusion controller.
The acid diffusion controller is not particularly limited as long as it acts as a quencher for trapping the acid of the acid component in the first layer. In the present invention, it is preferable to employ the nitrogen-containing organic compound component described as the component (D2) in the resist composition.
Further, it may be an ionic nitrogen-containing organic compound component, and is preferably a compound comprising a cation part represented by the following general formula (Cd) and an anion part represented by the above general formula (d1-1).

［Ｒｄ^ｃ１〜Ｒｄ^ｃ３は、それぞれ独立に、置換基を有していてもよいアルキル基である。］

^[Rd c1 ^{~ Rd c3} are each independently an alkyl group which may have a substituent. ]

In the formula (Cd), Rd ^{c1 to} Rdc ³ are each independently an alkyl group which may have a substituent. The Rd ^c1 ~ Rd ^c3, each independently, is preferably a linear alkyl group of 1 to 5 carbon atoms.

In the solution composed of the solvent, one of the above-described acid diffusion controllers may be used alone, or two or more thereof may be used in combination.
In the present invention, the content of the acid diffusion controller in the solvent solution is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 2.5 parts by mass, based on 100 parts by mass of the solvent solution. , 0.1 to 1 part by mass is more preferred.

[Polymer compound (Cp)]
Suitable polymer compounds (Cp) contained in the solvent solution include the same as the above-mentioned polymer compounds (Tp).
As the polymer compound (Cp), a combination of the structural unit represented by (Tp) -1-2 and the structural unit represented by (Tp) -1-3, and the above-described (Tp) -1-4 A combination of two or more structural units represented by the following formulas, a combination of the structural unit represented by the above (Tp) -1-1 and the structural unit represented by the above (Tp) -1-4, polyvinyl alcohol, Are preferred.

In the solution composed of the solvent, the above-described polymer compound (Cp) may be used alone or in a combination of two or more.
In the present invention, the content of the polymer compound (Cp) in the solution containing the acid or the thermal acid generator is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the solution containing the acid or the thermal acid generator. 0.5-5 mass parts is more preferred, and 0.6-2 mass parts is still more preferred.

  In the present invention, the solvent (B) contained in the solution containing the acid or the thermal acid generator forming the first layer and the solvent (C) contained in the solution comprising the solvent are different even if they are the same. Is also good. If different, for example, a monohydric alcohol solvent may be selected as the solvent (B), and an ether solvent may be adopted as the solvent (C). A solvent may be selected and an ether-based solvent may be employed as the solvent (B). Water may be selected as the solvent (B) and an ether-based solvent may be employed as the solvent (C). A monohydric alcohol solvent may be selected as B), and water may be used as the solvent (C).

  The amount of the solvent (C) to be used is not particularly limited, and is appropriately set at a concentration applicable to the first layer according to the thickness of the applied film. Generally, it is used so that the solid concentration of the solution comprising the solvent is in the range of 0.1 to 10% by mass, preferably 1 to 5% by mass.

[Step D]
Step D includes heating the structure including the first resist pattern obtained in Steps A to C, and dissolving the first resist pattern in a developer by the action of an acid in the first layer. Is a process of changing The heat treatment in the step (D) may be performed, for example, by baking at 90 to 110 ° C. for 50 to 120 seconds.

In the step (C), the action of the acid generated by the heat treatment in the subsequent step (D) can be controlled by applying the solvent solution so as to cover the first layer.
In the above [Step A], the first resist pattern 2 is formed by alkali development using a positive resist composition. That is, an alkali-insoluble region is formed on the surface of the resist pattern 2 in FIG.
In [Step D], the solubility of the first resist pattern 2 in a developing solution is changed by the action of an acid. Specifically, the surface of the first resist pattern is deprotected by the action of the acid in the first layer formed in [Step B], and the solubility in the organic solvent is reduced.
On the other hand, since the layer 4 made of a solvent is formed on the upper part of the pattern, it is considered that the action of acid is suppressed on the upper part of the pattern. For this reason, as shown in FIG. 1D, the heat treatment in [Step D] has the solubility in the first resist pattern in the region 2a in which the solubility in the organic solvent is reduced, and in the organic solvent. Region 2b is formed.

[Step E]
In the step (E), the coated first resist pattern is developed with an organic solvent, a region other than a region where the solubility of the first resist pattern in a developing solution is changed is removed, and a second resist pattern is formed. This is the step of forming.
In the step (D), as shown in FIG. 1D, in the first resist pattern, a region 2a having reduced solubility in the organic solvent and a region 2b having solubility in the organic solvent are formed. Therefore, by removing the region (2b in FIG. 1D) other than the region where the solubility of the first resist pattern in the developing solution has changed, the first resist pattern has a finer split pattern. Can be formed.

  The organic solvent contained in the organic solvent used for development includes a solution 4 composed of a solvent, a layer 3 containing an acid or a thermal acid generator, and a region 2b having solubility in an organic solvent. Any solvent may be used, and it can be appropriately selected from known organic solvents. Specifically, ketone-based solvents, ester-based solvents, nitrile-based solvents and the like can be mentioned. As the ester solvent, butyl acetate is preferred. As the ketone solvent, methyl amyl ketone (2-heptanone) is preferable.

  Ketone solvents are organic solvents containing CC (= O) -C in the structure. An ester solvent is an organic solvent containing CC (= O) -OC in its structure. The alcohol solvent is an organic solvent containing an alcoholic hydroxyl group in the structure, and the “alcoholic hydroxyl group” means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. An amide solvent is an organic solvent containing an amide group in the structure. Ether solvents are organic solvents containing C-O-C in the structure. Among the organic solvents, there is also an organic solvent containing a plurality of functional groups characterizing each of the above solvents in the structure, in which case, it corresponds to any solvent containing a functional group of the organic solvent. Shall be. For example, diethylene glycol monomethyl ether falls under both alcohol-based solvents and ether-based solvents in the above classification. The hydrocarbon solvent is a hydrocarbon solvent made of hydrocarbon and having no substituent (a group or atom other than a hydrogen atom and a hydrocarbon group).

  Specific examples of each solvent include ketone solvents such as 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutylketone, cyclohexanone, Methylcyclohexanone, phenylacetone, methylethylketone, methylisobutylketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methylnaphthylketone, isophorone, propylene carbonate, γ-butyrolactone, methylamylketone (2- Heptanone) and the like.

  Examples of the ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, methoxy acetate, ethyl ethoxy acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monoester. Propyl 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 monobutyl ether acetate, diethylene Recohol 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-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxy Methyl 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, pyruvine Methyl acetate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, 2-hydroxypropion Ethyl acid, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate and the like can be mentioned.

Examples of the nitrile-based solvent include acetonitrile, propionitrile, valeronitrile, butyronitrile and the like.
A known surfactant can be added to the organic developer as an additive, if necessary.

  The development using an organic developer can be carried out by a known development method, for example, a method in which a support is immersed in a developer for a certain period of time (dipping method), a method in which a developer is applied to a surface of a support with a surface tension. (Paddle method), spraying the developer on the surface of the support (spray method), and scanning the developer application nozzle at a constant speed on the support rotating at a constant speed. While the developer is continuously applied (dynamic dispensing method).

After the development processing and before drying, a rinsing treatment can be performed using a rinsing solution containing an organic solvent. By performing the rinsing, a good pattern can be formed.
As the organic solvent used for the rinsing liquid, for example, among the organic solvents listed as the organic solvent used for the organic developing solution, those that hardly dissolve the resist pattern can be appropriately selected and used. Usually, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents and ether solvents is used. Among these, at least one selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents and amide solvents is preferred, and at least one selected from alcohol solvents and ester solvents is preferred. More preferred are alcohol solvents.
The alcohol solvent used for the rinsing liquid is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be linear, branched or cyclic. Specific examples include 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol, and the like. Can be Among these, 1-hexanol, 2-heptanol and 2-hexanol are preferred, and 1-hexanol or 2-hexanol is more preferred.
One of these organic solvents may be used alone, or two or more thereof may be used in combination. Further, it may be used by mixing with an organic solvent or water other than the above. However, considering the development characteristics, the amount of water in the rinsing solution is preferably 30% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, and more preferably 3% by mass or less based on the total amount of the rinsing solution. Is particularly preferred.
Known additives can be added to the organic developer as needed. Examples of the additive include a surfactant. Examples of the surfactant include the same as described above, and a nonionic surfactant is preferable, and a fluorine-based surfactant or a silicon-based surfactant is more preferable.
When a surfactant is blended, the blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass based on the total amount of the rinsing liquid. % Is more preferred.
The rinsing treatment (cleaning treatment) using a rinsing liquid can be carried out by a known rinsing method, such as a method of continuously applying the rinsing liquid onto a support rotating at a constant speed (rotation coating method). And a method in which the support is immersed in a rinsing liquid for a predetermined time (dip method), and a method in which the rinsing liquid is sprayed on the surface of the support (spray method).

According to the method for forming a resist pattern of the present invention, a so-called split pattern, which is a fine pattern obtained by dividing the first resist pattern, can be favorably formed.
The reason is presumed as follows.
The method of forming a resist pattern according to the present invention includes the [Step C], whereby the action of the acid in the first layer above the first resist pattern is suppressed while the second resist on the side face of the first resist pattern is suppressed. Since the acid in the first layer can act, the solubility of the first resist pattern in the central part and the side wall part in the developing solution can be controlled. For this reason, it is considered that pattern separation can be improved.
In the method of forming a resist pattern according to the present invention, when a predetermined solvent or polymer compound is used in the first layer and the layer composed of the solvent, dissolution of the first resist pattern, It is considered that the layer of the above and the layer made of the solvent can be prevented from being entirely mixed. In addition to this, in the organic solvent development in [Step E], the solubility in the organic solvent can be made favorable, so it is presumed that a desired split pattern can be obtained.

≪Resist pattern splitting agent≫
A second aspect of the present invention is a resist pattern splitting agent used for coating a resist pattern and splitting the resist pattern, comprising at least a solvent and an acid or a thermal acid generator. Resist pattern splitting agent.
According to the resist pattern splitting agent of the present invention, a formed resist pattern can be split (divided) to form a finer pattern.

The description of the resist pattern covered by the resist pattern splitting agent of the present invention and the resist composition used for forming the resist pattern is described in the first resist pattern forming method according to the first aspect of the present invention. This is the same as the description of the pattern and the resist composition used to form the first resist pattern.
The description of the resist pattern splitting agent of the present invention is the same as the description of the solution containing an acid or a thermal acid generator used in [Step B] in the resist pattern forming method of the first aspect of the present invention. .

That is, the description of the solvent contained in the resist pattern splitting agent of the present invention is the same as the description of the solvent (B), and the solvent contained in the resist pattern splitting agent has a linear or It preferably contains a branched monovalent alcohol, and the description of the linear or branched monovalent alcohol having 1 to 10 carbon atoms is the same as that of the solvent (B).
The description of the acid or thermal acid generator contained in the resist pattern splitting agent of the present invention is the same as that of the component (T0) or (T1).
Further, the resist pattern splitting agent of the present invention preferably contains a polymer compound in order to improve coatability and make it removable by a developing treatment after splitting.
The polymer compound preferably contained in the resist pattern splitting agent of the present invention includes the polymer compound (Tp).

≪Split pattern improver≫
A third aspect of the present invention is a split pattern improver. The split pattern improving agent of the present invention is a split pattern improving agent for coating a resist pattern with the resist pattern splitting agent and then coating the resist pattern, and contains at least an organic solvent and an acid diffusion controller.
The description of the split pattern improving agent of the present invention is the same as the description of the solvent solution used in [Step C] of the method for forming a resist pattern according to the first aspect of the present invention.
That is, the description of the solvent contained in the split pattern improving agent of the present invention is the same as that of the solvent (C), and preferably further contains an acid diffusion controller and a polymer compound. The description of the acid diffusion controller is the same as the description of the acid diffusion controller described in [Step C].
The polymer compound contained in the split pattern improving agent of the present invention is preferably the polymer compound (Cp).

≪Resist pattern split material≫
A fourth aspect of the present invention is a resist pattern split material comprising the resist pattern splitting agent and the split pattern improving agent. The description of the resist pattern splitting agent and the split pattern improving agent is the same as described above.
By using the resist pattern splitting agent in combination with the split pattern improving agent, good pattern separation (split) can be achieved. Further, the overall mixing of the resist pattern splitting agent and the split pattern improving agent is unlikely to occur, and in addition, since it can be removed in the developing step, the handleability is excellent.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples.

<< Examples 1-30 >>
[Step A]
<Preparation of resist composition>
100 parts by weight of the following polymer compound (A) -1, 10 parts by weight of the following compound (B) -1, 7 parts by weight of the following compound (D) -1, and 2 parts by weight of the following polymer compound (F)- 1,2 parts by mass of salicylic acid and 4000 parts by mass of a solvent (mixed solvent of PGMEA / PGME / cyclohexanone (mass ratio 45/30/25)) were mixed to prepare a resist composition.

<Formation of First Resist Pattern: Alkaline Developed Positive Pattern>
On a 12-inch silicon wafer, an organic anti-reflective coating composition "ARC29A" (trade name, manufactured by Brewer Science) is applied using a spinner, baked on a hot plate at 205 ° C. for 60 seconds, and dried. Thus, an organic antireflection film having a thickness of 85 nm was formed.
Next, the above-mentioned resist composition is applied on the film using a spinner, prebaked (PAB) at a temperature of 90 ° C. for 60 seconds on a hot plate, and dried to obtain a film thickness of 60 nm. Was formed.
Next, an ArF excimer laser (193 nm) was applied to the resist film through a mask pattern (binary mask) using an exposure apparatus NSR-S609B (NA = 1.07 Dipole 0.97 / 0.78 with pollano, manufactured by Nikon Corporation). Irradiated selectively.
Next, alkali development was performed at 23 ° C. for 30 seconds using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) “NMD-3” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.).
Thereafter, a post-exposure bake treatment was performed at 100 ° C. (PEB (° C.)) for 60 seconds.
As a result, a line & space pattern (hereinafter, referred to as “LS pattern”) having a space width of 40 nm and a line width of 120 nm was formed.

[Step B]
<Preparation of solution containing acid component>
As shown in the following table, an acid component, a polymer and a solvent were mixed to prepare a solution containing the acid component (hereinafter, referred to as “first solution”).
<Formation of First Layer>
The first solution was applied on the first resist pattern obtained in the above [Step A] using a spinner to form a first layer. The coating thickness of the solution containing the acid component is shown in the following table.

[Step C]
<Preparation of solvent solution>
As shown in the following table, an acid component, a polymer, and a solvent were mixed to prepare a solution composed of the solvent (hereinafter, referred to as “second solution”).
<Application of solution consisting of solvent>
The second solution was applied using a spinner so as to cover the first layer obtained in [Step B].

[Step D]
The structure including the first resist pattern obtained in the steps A to C was baked at each temperature shown in the following table for 60 seconds.

[Step E]
After [Step D], a developing treatment was performed for 13 seconds using butyl acetate. Thus, a split pattern was formed.

<< Comparative Examples 1-6 >>
[Step A] and [Step B] were performed in the same manner as in the above {Examples 1 to 30} to form a first layer. Thereafter, the structure including the first resist pattern was baked at each temperature shown in the following table for 60 seconds, and developed with butyl acetate for 13 seconds.

  In the above table, each abbreviation has the following meaning. Numerical values in [] are blending amounts (parts by mass).

<Evaluation of split pattern>
For the formed split pattern, pattern separation and CD were evaluated.
[Pattern separation]
The split pattern was observed with a length-measuring SEM (scanning electron microscope, acceleration voltage 300 V, trade name: S-9380, manufactured by Hitachi High-Technologies Corporation), and the pattern separation was evaluated in the following five stages. The results are shown in the table below.
[Pattern separation evaluation standard]
1 ... The pattern is almost dissolved and cannot be confirmed 2 ... A split pattern is obtained but partially collapsed 3 ... A split pattern is obtained and there is no collapse or connection between patterns 4 ... Split A pattern is obtained, but some of the patterns are connected 5... Maintaining the first resist pattern and not forming a split pattern [Evaluation of pattern dimensions]
100 locations in the pattern were observed from above the pattern with a length-measuring SEM (scanning electron microscope, acceleration voltage 300 V, trade name: S-9380, manufactured by Hitachi High-Technologies Corporation), and each line width (nm) was measured. did. The results are shown in the following table as "CD (nm)".

  As shown in the above results, in Examples 1 to 30 in which the second solution was applied so as to cover the first layer, a split pattern was formed and the pattern dimensions were good. On the other hand, in Comparative Examples 1 to 6 in which the second solution was not applied, the patterns did not separate, no split pattern was formed, or the first resist pattern was dissolved.

<< Examples 31-39 >>
<Preparation of resist composition>
The polymer compounds 1 to 9 having the structures shown in Table 9 below were used, and the monomers (1) to (9) corresponding to the respective structural units constituting the polymer compound were used in a molar ratio shown in Table 9 by a conventional method. Synthesized.

  The components shown in Table 10 below were mixed and dissolved to prepare resist compositions 2 to 10.

In Table 10, each abbreviation shows the following, and the numerical value in [] is a compounding quantity (mass part).
(A) -2 to (A) -10: The above polymer compounds 1 to 9
(B) -1: the above compound (B) -1
(D) -1: The above compound (D) -1
(F) -1: The above polymer compound (F) -1
(S) -1: a mixed solvent of PGMEA / PGME / cyclohexanone (mass ratio 45/30/25).

  For the above resist compositions 2 to 10, the maximum value (Rmax, unit: nm / s) and the minimum value (Rmin, unit: nm / s) of the dissolution rate (film reduction amount / immersion time) in butyl acetate are determined by the following methods. Table 10 shows the measurement results.

[Measurement of dissolution rate]
Each of the resist compositions 2 to 10 was uniformly applied on an 8-inch silicon substrate using a spinner, and prebaked (PAB) at 110 ° C. for 60 seconds on a hot plate to have a thickness of 160 nm. Was formed.
The resist film is immersed in butyl acetate at 23 ° C. for 10 seconds, and the maximum value (R _max , unit: nm / s) and the minimum value (R _min ) of the dissolution rate (film reduction amount / immersion time) at that time. , Unit: nm / s) was determined by RDA-808RB (trade name, manufactured by Lithotec Japan).

[Step A]
<Formation of First Resist Pattern: Alkaline Developed Positive Pattern>
On a 12-inch silicon wafer, an organic antireflection coating composition "ARC29A" (trade name, manufactured by Brewer Science) is applied using a spinner, baked on a hot plate at 205 ° C. for 60 seconds, and dried. Thus, an organic antireflection film having a thickness of 85 nm was formed.
Next, the above-described resist compositions 2 to 10 are respectively applied to the film using a spinner, prebaked (PAB) at a temperature of 90 ° C. for 60 seconds on a hot plate, and dried. A resist film having a thickness of 60 nm was formed.
Then, an ArF excimer laser (193 nm) was applied to the resist film through a mask pattern (binary mask) using an exposure apparatus NSR-S609B (NA = 1.07 Dipole 0.97 / 0.78 with pollano, manufactured by Nikon Corporation). Irradiated selectively.
Next, alkali development was performed at 23 ° C. for 10 seconds using a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution “NMD-3” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.).
Thereafter, a post-exposure bake was performed at 90 ° C. (PEB (° C.)) for 60 seconds.
As a result, a line & space pattern (hereinafter, referred to as “LS pattern”) having a pitch width of 160 nm and a line width of 120 nm was formed.

[Step B]
<Preparation of solution containing acid component>
The same acid component, polymer and solvent as in Example 21 were mixed to prepare a solution containing the acid component (hereinafter, referred to as “first solution”).
<Formation of First Layer>
The first solution was applied on the first resist pattern obtained in [Step A] using a spinner (1500 rpm) to form a first layer. The coating thickness of the solution containing the acid component was 20 nm.

[Step C]
<Preparation of solvent solution>
The same acid component, polymer and solvent as in Example 21 were mixed to prepare a solution composed of the solvent (hereinafter, referred to as “second solution”).
<Application of solution consisting of solvent>
The second solution was applied using a spinner so as to cover the first layer obtained in [Step B].

[Step D]
The structure including the first resist pattern obtained in the steps A to C was baked at 110 ° C. for 60 seconds.

[Step E]
After [Step D], a developing treatment was performed for 13 seconds using butyl acetate. Thus, a split pattern was formed. Thereafter, a post-development heat treatment was performed at 100 ° C. for 45 seconds.

<Evaluation of split pattern>
For the formed split pattern, pattern separation was evaluated.
[Pattern separation]
The split pattern was observed with a length-measuring SEM (scanning electron microscope, acceleration voltage 300 V, trade name: S-9380, manufactured by Hitachi High-Technologies Corporation), and the pattern separation was evaluated in the following five stages. The results are shown in the table below.
[Pattern separation evaluation standard]
1 ... The pattern is almost dissolved and cannot be confirmed 2 ... A split pattern is obtained but partially collapsed 3 ... A split pattern is obtained and there is no collapse or connection between the patterns 4 ... Split A pattern is obtained, but some of the patterns are connected. 5 ... The first resist pattern is maintained and no split pattern is formed.

  As shown in Table 11, when the maximum value of the dissolution rate of the resist composition for forming the first resist pattern was 5 nm / s or more and the minimum value was 1 nm / s or less, the patterns could be separated well. .

DESCRIPTION OF SYMBOLS 1 ... Support body, 2 ... First resist pattern, 3 ... First layer, 4 ... Solution made of solvent, 2a ... Area with reduced solubility in organic solvent, 2b ... Area having solubility in organic solvent

Claims (8)

A step A of forming a first resist pattern on a support by forming a positive resist film, exposing the positive resist film to light, and developing with an alkali;
A step B of applying a solution containing an acid or a thermal acid generator so as to cover the first resist pattern to form a first layer;
A step C of applying a solution containing a solvent so as to cover the first layer;
Heating the structure including the first resist pattern obtained in the steps A to C, and changing the solubility of the first resist pattern in a developer by the action of an acid in the first layer; D and
A step E of developing the coated first resist pattern with an organic solvent, removing a region other than a region in which the solubility of the first resist pattern in a developer has changed, and forming a second resist pattern; A method of forming a resist pattern, comprising:   The method according to claim 1, wherein the solution containing the solvent further contains an acid diffusion controller.   3. The method according to claim 2, wherein the acid diffusion controller includes a nitrogen-containing organic compound. The method for forming a resist pattern according to any one of claims 1 to 3, wherein the thermal acid generator includes a compound represented by any of the following general formulas (T1-1) to (T1-3).

[Wherein, Rt ¹⁰¹ , Rt ^{104 to} Rt ¹⁰⁸ each independently have a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a substituent. A chain alkenyl group which may be substituted. Rt ¹⁰⁴ and Rt ¹⁰⁵ may be bonded to each other to form a ring. Any two of Rt ^{106 to} Rt ¹⁰⁷ may be mutually bonded to form a ring. Rt ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. Yt ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom. Vt ^{101 to} Vt ¹⁰³ are each independently a single bond, an alkylene group, or a fluorinated alkylene group. Lt ^{101 to} Lt ¹⁰² are each independently a single bond or an oxygen atom. Lt ^{103 to} Lt ¹⁰⁵ are each independently a single bond, —CO— or —SO ₂ —. Rt ^{301 to} Rt ³⁰⁴ are each independently a hydrogen atom or a linear, branched or cyclic fluorinated alkyl group having 1 to 12 carbon atoms. Rt ^{301 to} Rt ³⁰³ may combine with each other to form a ring together with the nitrogen atom in the formula. ]   The method for forming a resist pattern according to any one of claims 1 to 4, wherein the solution containing the acid or the thermal acid generator has a structural unit (a3) containing a polar group-containing aliphatic hydrocarbon group.   The resist pattern forming method according to any one of claims 1 to 5, wherein the solution containing the acid or the thermal acid generator contains a linear or branched monovalent alcohol having 1 to 10 carbon atoms.   The method for forming a resist pattern according to any one of claims 2 to 6, wherein the solution containing the acid diffusion controller has a structural unit (a4) containing an acid non-dissociable cyclic group.   The resist pattern forming method according to claim 2, wherein the solution containing the acid diffusion controller contains a low-polarity solvent.

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