JP2010037528A - Compound, radical polymerization initiator, polymer, resist composition, method for forming resist pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition, especially, a polymer useful as a resist composition for liquid immersion exposure, a compound useful as a radical polymerization initiator used for manufacturing the polymer, a radical polymerization initiator including the compound, a resist composition containing the polymer, and a method for forming a resist pattern. <P>SOLUTION: The polymer has a group expressed by general formula (i-1) in at least one end of a main chain. The compound is expressed by general formula (I). The radical polymerization initiator includes the compound. The resist composition contains the polymer. In the formulas, R<SP>1</SP>is alkylene group which may have a substituent group. R<SP>2</SP>is an organic group which defines -O-R<SP>2</SP>in the formulas as a base dissociable group to be dissociated by the action of an alkali developer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a compound useful as a radical polymerization initiator, a radical polymerization initiator comprising the compound, a polymer useful as a resist composition, a resist composition containing the polymer, and a resist pattern forming method.

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 light such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film.
Along with the miniaturization of semiconductor elements, the wavelength of an exposure light source has been shortened and the projection lens has a high numerical aperture (high NA). A machine has been developed. Along with the shortening of the wavelength of the exposure light source, the resist material is required to be improved in lithography characteristics such as sensitivity to the exposure light source and resolution capable of reproducing a pattern with a fine dimension. As a resist material that satisfies such requirements, a chemically amplified resist containing a base resin whose solubility in an alkaline developer is changed by the action of an acid and an acid generator that generates an acid upon exposure is used.
Currently, as a base resin of a chemically amplified resist used in ArF excimer laser lithography and the like, a resin having a structural unit derived from (meth) acrylic acid ester in the main chain because of its excellent transparency near 193 nm ( Acrylic resin) is generally used. Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.

As one of the techniques for further improving the resolution, exposure (immersion exposure) is performed by interposing a liquid (immersion medium) having a higher refractive index than air between the objective lens of the exposure machine and the sample. A so-called immersion lithography (hereinafter referred to as “immersion exposure”) is known (for example, see Non-Patent Document 1).
According to immersion exposure, even when a light source having the same exposure wavelength is used, the same high resolution as when using a light source with a shorter wavelength or a high NA lens can be achieved, and the depth of focus can be reduced. It is said that there is no decline. Moreover, immersion exposure can be performed using an existing exposure apparatus. Therefore, immersion exposure is expected to be able to form a resist pattern with low cost, high resolution, and excellent depth of focus, and in the manufacture of semiconductor devices that require a large capital investment. In particular, in terms of lithography characteristics such as resolution, the semiconductor industry is attracting a great deal of attention.
Immersion exposure is effective in the formation of all pattern shapes, and can be combined with super-resolution techniques such as the phase shift method and the modified illumination method that are currently being studied. Currently, as an immersion exposure technique, a technique mainly using an ArF excimer laser as a light source is being actively researched. Currently, water is mainly studied as an immersion medium.

In recent years, with respect to fluorine-containing compounds, attention has been paid to characteristics such as water repellency and transparency, and research and development in various fields has been actively conducted. For example, in the field of resist materials, acid instabilities such as methoxymethyl group, tert-butyl group, and tert-butyloxycarbonyl group are added to fluorine-containing polymer compounds for use as the base resin of positive chemically amplified resists. Introducing groups. However, when such a fluorine-based polymer compound is used as a base resin of a positive resist composition, there are disadvantages such as generation of a large amount of outgas after exposure and insufficient resistance to dry etching gas (etching resistance). is there.
Recently, a fluorine-containing polymer compound having an acid labile group containing a cyclic hydrocarbon group has been reported as a fluorine-containing polymer compound having excellent etching resistance (see, for example, Non-Patent Document 2). In addition, in a resist composition for immersion exposure, a fluorine-containing polymer compound has been reported to impart water repellency to a resist film (for example, see Non-Patent Document 3).
Proceedings of SPIE, 5754, 119-128 (2005). Proceedings of SPIE, 4690, 76-83 (2002). Journal of Photopolymer Science and Technology, Vol. 19, No. 19 4, 565-568 (2006).

In immersion exposure, in addition to normal lithography characteristics (sensitivity, resolution, etching resistance, etc.), a resist material having characteristics corresponding to the immersion exposure technique is required. For example, in immersion exposure, when a resist film and an immersion solvent come into contact with each other, elution of the substance in the resist film into the immersion solvent (substance elution) occurs. Substance elution causes phenomena such as alteration of the resist layer and change in the refractive index of the immersion solvent, thereby deteriorating the lithography properties.
Further, when the immersion medium is water, when immersion exposure is performed using a scanning immersion exposure machine as described in Non-Patent Document 1, the immersion medium follows the movement of the lens. Therefore, the water following ability to move is required. If the water followability is low, the exposure speed is lowered, and there is a concern that the productivity may be affected.
Since the amount of the substance elution is affected by the characteristics (for example, hydrophilicity / hydrophobicity) of the resist film surface, it is considered that the substance elution can be reduced by increasing the hydrophobicity of the resist film surface, for example. In addition, it is considered that the water followability is also improved by increasing the hydrophobicity (hydrophobizing) of the resist film surface.
Thus, it is thought that by increasing the hydrophobicity of the resist film surface, it is possible to solve the problems peculiar to the immersion exposure technology such as reduction of substance elution and improvement of water followability. Even if it is hydrophobized, there is an adverse effect on lithography properties and the like. For example, when the hydrophobicity of the resist film increases, there is a problem that a defect is likely to occur in the resist film after alkali development. In particular, in the case of a positive resist composition, defects tend to occur in unexposed areas. The “defect” is a general defect detected when the developed resist film is observed from directly above, for example, by a surface defect observation apparatus (trade name “KLA”) manufactured by KLA Tencor. Examples of the defects include scum, bubbles, dust, bridges (bridge structures between resist patterns), color unevenness, precipitates, and residues after development.
It is presumed that these problems can be solved if the material has characteristics that are hydrophobic during immersion exposure and hydrophilic during development. However, there are currently few known materials having such characteristics.
The present invention has been made in view of the above circumstances, and is a resist composition, particularly a polymer useful as a resist composition for immersion exposure, and a compound useful as a radical polymerization initiator used in the production of the polymer. It is an object of the present invention to provide a radical polymerization initiator comprising the compound, a resist composition containing the polymer, and a resist pattern forming method.

In order to achieve the above object, the present invention employs the following configuration.
That is, the first aspect of the present invention is a polymer having a group represented by the following general formula (i-1) at at least one end of the main chain.

［式中、Ｒ^１は置換基を有していてもよいアルキレン基であり；Ｒ^２は、当該式中の−Ｏ−Ｒ^２を、アルカリ現像液の作用により解離する塩基解離性基とする有機基である。］

[Wherein, R ¹ represents an alkylene group which may have a substituent; R ² represents —O—R ² in the formula as a base dissociable group that dissociates by the action of an alkali developer. Organic group. ]

  The second aspect of the present invention is a compound represented by the following general formula (I).

［式中、Ｒ^１は置換基を有していてもよいアルキレン基であり；Ｒ^２は、当該式中の−Ｏ−Ｒ^２を、アルカリ現像液の作用により解離する塩基解離性基とする有機基である。］

[Wherein, R ¹ represents an alkylene group which may have a substituent; R ² represents —O—R ² in the formula as a base dissociable group that dissociates by the action of an alkali developer. Organic group. ]

The third aspect of the present invention is a radical polymerization initiator comprising the compound of the second aspect.
A fourth aspect of the present invention is a resist composition containing the polymer of the first aspect.
According to a fifth aspect of the present invention, there is provided a chemically amplified resist comprising a base component (A) whose solubility in an alkaline developer is changed by the action of an acid, and an acid generator component (B) which generates an acid upon exposure. It is a composition, Comprising: The said base material component (A) is a resist composition containing the base material component (A1) which consists of a polymer of said 1st aspect.
According to a sixth aspect of the present invention, there is provided a substrate component (A ′) whose solubility in an alkaline developer is changed by the action of an acid, an acid generator component (B ′) that generates an acid upon exposure, and the first component It is a resist composition containing the additive component (C ') which consists of a polymer of an aspect.
According to a seventh aspect of the present invention, there is provided a step of forming a resist film on a support using the resist composition of any one of the fourth to sixth aspects, a step of exposing the resist film, and the resist This is a resist pattern forming method including a step of forming a resist pattern by alkali development of a film.

In the present specification and claims, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The “lower alkyl group” is an alkyl group having 1 to 5 carbon atoms.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
“Aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.
“Structural unit” means a monomer unit (monomer unit) constituting a resin component (polymer, copolymer).
“Exposure” is a concept including general irradiation of radiation.

  According to the present invention, a resist composition, particularly a polymer useful as a resist composition for immersion exposure, a compound useful as a radical polymerization initiator used in the production of the polymer, a radical polymerization initiator comprising the compound, A resist composition containing the polymer and a method for forming a resist pattern can be provided.

≪Compound≫
First, the compound of the second aspect of the present invention will be described.
The compound is a compound represented by the general formula (I) (hereinafter referred to as compound (I)).
In formula (I), the alkylene group in R ¹ may be linear, branched or cyclic, and a combination of a linear or branched alkylene group and a cyclic alkylene group It may be.

The linear or branched alkylene group preferably has 1 to 5 carbon atoms in the main chain, more preferably 1 to 4, still more preferably 1 to 3, and most preferably 3.
Specific examples of the linear alkylene group include a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [— (CH ₂ ) ₃ —], a tetramethylene group [ _{- (CH 2) 4 -]} , a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
Examples of the branched alkylene group include a group in which a linear or branched alkyl group is bonded to the linear alkylene group. The alkyl group is preferably linear. 1-5 are preferable, as for carbon number of this alkyl group, 1-3 are more preferable, and 1 or 2 is further more preferable. Specifically, as the branched alkylene group, —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 - alkyl 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 -, - 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 - , etc. Le Kill tetramethylene group and the like.
The cyclic alkylene group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The cyclic alkylene group may be monocyclic or polycyclic.
The monocyclic alkylene group is preferably a group in which two hydrogen atoms are removed from a monocycloalkane having 3 to 6 carbon atoms, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic alkylene group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, and tricyclodecane. And tetracyclododecane.
In the cyclic alkylene group, a linear or branched alkyl group may be bonded to a carbon atom constituting the ring. Examples of the alkyl group include those described above.

The alkylene group in R ¹ may have a substituent.
The term “having a substituent” for an alkylene group means that part or all of the hydrogen atoms in the alkylene group are substituted with groups or atoms other than hydrogen atoms.
Preferable examples of the substituent that the alkylene group in R ¹ may have include a cyano group.

In the present invention, R ¹ is preferably a branched alkylene group which may have a substituent. Moreover, it is preferable that the cyano group as a substituent is couple | bonded with the carbon atom couple | bonded with a nitrogen atom.
Preferable specific examples of R ¹ include —C (CH ₃ ) (CN) — (CH ₂ ) _n —, —C (CH ₃ ) ₂ — (CH ₂ ) _n —, and the like. In the formula, n is an integer of 0 to 4, more preferably 0 to 3, particularly preferably 0 to 2, and most preferably 2.
In the formula (I), two R ^{1 s} may be the same or different, and are preferably the same.

R ² is an organic group in which —O—R ² in the formula is a base dissociable group that dissociates by the action of an alkali developer.
Here, the “organic group” is a group containing at least one carbon atom in its structure.
The “base dissociable group” is a group that dissociates by the action of an alkali developer (alkaline aqueous solution). The alkali developer may be one generally used in the lithography field. In the present invention, the base dissociable group is preferably a group capable of dissociating by the action of a 2.38% by mass tetramethylammonium hydroxide aqueous solution.
In the compound (I), by having R ² , when contacting with an alkali developer, the carbon atom of the carbonyl group (C═O) in the structure and the oxygen atom (—O bonded to the carbon atom) The bond with-) can be broken. That is, when the compound (I) is brought into contact with an alkali developer, the bond between the carbonyl group in the formula (I) and —O—R ² bonded to the carbon atom of the carbonyl group is broken by hydrolysis. And —O—R ² dissociates and at the same time a carbonyl group is formed.

Whether or not —O—R ² in formula (I) is dissociated by the action of an alkali developer is subjected to the following alkali treatment, neutralized, and then a known analytical method (for example, thin layer chromatography (TLC)). This can be confirmed by confirming whether or not the ester (compound (I)) has disappeared.
(Alkali treatment)
A solvent (for example, tetrahydrofuran) for dissolving the compound (I) and an aqueous 2.38 mass% tetramethylammonium hydroxide solution are added to the compound (I), and the mixture is stirred at 23 ° C. for 60 seconds.

As R ² , when the alkali treatment as described above is performed, the bond between the carbon atom of the carbonyl group in the structure and the oxygen atom (—O—) bonded to the carbon atom can be broken. What is necessary.
Specific examples of R ² include a hydrocarbon group having an electron withdrawing group.
The “hydrocarbon group having an electron withdrawing group” is a group in which part or all of the hydrogen atoms of the hydrocarbon group are substituted with an electron withdrawing group.
In the hydrocarbon group having an electron withdrawing group, the “hydrocarbon group” to which the electron withdrawing group is bonded may be linear, branched or cyclic, and should be linear or branched. Is preferable, and it is more preferable that it is linear.
The hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, particularly preferably 1 to 10 carbon atoms, and most preferably 1 to 5 carbon atoms.
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, but is preferably an aliphatic hydrocarbon group.
The aliphatic hydrocarbon group is a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group may be either saturated or unsaturated, but is usually preferably a saturated aliphatic hydrocarbon group (alkyl group).

More specifically, examples of the hydrocarbon group having an electron withdrawing group include groups in which some or all of the hydrogen atoms of the unsubstituted alkyl group described below are substituted with an electron withdrawing group.
The unsubstituted alkyl group may be linear, branched or cyclic, or a combination of a linear or branched alkyl group and a cyclic alkyl group.
As an unsubstituted linear alkyl group, C1-C10 is preferable and C1-C8 is more preferable. Specifically, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n- A decanyl group etc. are mentioned.
As an unsubstituted branched alkyl group, C3-C10 is preferable and C3-C8 is more preferable. As the branched alkyl group, a tertiary alkyl group is preferable.
Examples of the unsubstituted cyclic alkyl group include groups in which one hydrogen atom has been removed from a monocycloalkane or a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. Specific examples include monocycloalkyl groups such as cyclopentyl group and cyclohexyl group; polycycloalkyl groups such as adamantyl group, norbornyl group, isobornyl group, tricyclodecanyl group and tetracyclododecanyl group.
A combination of an unsubstituted linear or branched alkyl group and a cyclic alkyl group includes a group in which a cyclic alkyl group is bonded as a substituent to a linear or branched alkyl group, or a cyclic alkyl group And a group having a linear or branched alkyl group bonded thereto as a substituent.

The electron withdrawing group is not particularly limited and may be a known one.
A preferable electroattractive group includes a fluorine atom. That is, R ² is preferably a hydrocarbon group having a fluorine atom. When R ² contains a fluorine atom, the hydrophobicity of the polymer obtained using the compound (I) as a radical polymerization initiator is further improved, and when —O—R ² is dissociated by the action of an alkali developer. The effect of improving the hydrophilicity is further increased.
Since the hydrocarbon group having a fluorine atom increases the hydrophobicity of the resist film during immersion exposure, the fluorination rate is preferably 25% or more, more preferably 50% or more, and 60% or more. It is particularly preferred that The “fluorination rate” is the ratio (%) of [number of fluorine atoms] to [total number of hydrogen atoms and fluorine atoms] in the hydrocarbon group.

In R ² , the hydrocarbon group having a fluorine atom is preferably a fluorinated alkyl group, more preferably a linear or branched fluorinated alkyl group.
The fluorinated alkyl group may be a group in which some of the hydrogen atoms of the unsubstituted alkyl group are substituted with fluorine atoms, or a group in which all of the hydrogen atoms of the unsubstituted alkyl group are substituted with fluorine atoms ( Perfluoroalkyl group).
In the present invention, a fluorinated alkyl group having 2 or more carbon atoms and in which a fluorine atom is not directly bonded to a carbon atom bonded to an adjacent oxygen atom (—O—) is particularly preferable. Moreover, it is preferable that the fluorine atom has couple | bonded with the carbon atom of the terminal of this fluorinated alkyl group.
Preferred examples of the fluorinated alkyl group as R ² include groups represented by the following general formula (III-1) or (III-2). Among these, the group represented by the formula (III-1) is preferable.

［式（ＩＩＩ−１）中、Ｒ^４１’は無置換のアルキレン基であり、Ｒ^４２’はフッ素化アルキル基である。但し、Ｒ^４１’とＲ^４２’との炭素数の合計は１０以下である。また、式（ＩＩＩ−２）中、Ｒ^７１〜Ｒ^７３は、それぞれ独立に、水素原子またはフッ素原子を有していてもよい炭素数１〜５の直鎖状のアルキル基であり、Ｒ^７１〜Ｒ^７３の少なくとも１つはフッ素原子を有するアルキル基である。］

[In the formula (III-1), R ⁴¹ ′ is an unsubstituted alkylene group, and R ⁴² ′ is a fluorinated alkyl group. However, the total number of carbon atoms of R ⁴¹ ′ and R ⁴² ′ is 10 or less. In formula (III-2), R ^{71 to} R ⁷³ are each independently a linear alkyl group having 1 to 5 carbon atoms which may have a hydrogen atom or a fluorine atom, and R ⁷¹ at least one of to R ⁷³ is an alkyl group having a fluorine atom. ]

In formula (III-1), the alkylene group for R ⁴¹ ′ may be linear, branched or cyclic, preferably linear or branched, and more preferably linear. Moreover, 1-9 are preferable and, as for the carbon number, 1-5 are more preferable. R ⁴¹ ′ is particularly preferably a methylene group, an ethylene group or a propylene group.
R ⁴² ′ is preferably a linear or branched fluorinated alkyl group, and more preferably linear. 1-9 are preferable and, as for the carbon number, 1-5 are more preferable. R ⁴² ′ is particularly preferably a perfluoroalkyl group.
As the group represented by the formula (III-1), in particular, —CH ₂ —CF ₃ , —CH ₂ —CF ₂ —CF ₃ , —CH ₂ —CF ₂ —CF ₂ —CF ₃ , —CH ₂ — _{CH 2 -CF 2 -CF 2 -CF 2} -CF 3 is preferred.
In formula (III-2), the alkyl group in R ^{71 to} R ⁷³ “C1-C5 linear alkyl group optionally having fluorine atoms” is preferably an ethyl group or a methyl group. In particular, a methyl group is preferable.
At least one of R ^{71 to} R ⁷³ is an alkyl group having a fluorine atom (fluorinated alkyl group). All of R ^{71 to} R ⁷³ may be fluorinated alkyl groups, but at least one is preferably a hydrogen atom.
As the group represented by the formula (III-2), —CH (CF ₃ ) ₂ is particularly preferable.
Among these, _{^{R 2, -CH 2 -CF 3,}} -CH 2 -CF 2 -CF 3, -CH (CF 3) 2, -CH 2 -CF 2 -CF 2 -CF 3, -CH 2 are _{-CH 2 -CF 2 -CF 2 -CF 2} -CF 3 particularly preferred.
In formula (I), two R ^{2 s} may be the same or different, but are preferably the same.

  Specific examples of compound (I) are shown below.

<Method for Producing Compound (I)>
The production method of compound (I) is not particularly limited. For example, R ² [R ² is as defined above] for the carboxy group of the compound (I-01) represented by the following general formula (I-01). ] (Replace the hydrogen atom at the terminal of the carboxy group with R ² ).
R ² can be introduced using a conventionally known method. For example, compound (I) can be produced by reacting compound (I-01) with compound (I-02) represented by general formula (I-02) below.

［式中、Ｒ^１、Ｒ^２はそれぞれ前記と同じである。］

[Wherein, R ¹ and R ² are the same as defined above. ]

The method for reacting compound (I-01) with compound (I-02) is not particularly limited, and for example, compound (I-01) and compound (in the reaction solvent in the presence of a base and a condensing agent). And a method of contacting I-02).
As compound (I-01) and compound (I-02), commercially available compounds or synthesized compounds may be used. For example, as compound (I-02), a fluorinated alkyl alcohol or the like can be used.
Any reaction solvent may be used as long as it can dissolve the starting compounds (I-01) and (I-02). Specifically, tetrahydrofuran (THF), acetone, dimethylformamide (DMF), dimethylacetamide , Dimethyl sulfoxide (DMSO), acetonitrile and the like.
Examples of the base include organic bases such as triethylamine, 4-dimethylaminopyridine (DMAP) and pyridine; inorganic bases such as sodium hydride, K ₂ CO ₃ and Cs ₂ CO ₃ .
Examples of the condensing agent include carbodiimide reagents such as ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride, dicyclohexylcarboimide (DCC), diisopropylcarbodiimide, carbodiimidazole, tetraethylpyrophosphate, benzotriazole-N-hydroxytrisdimethylaminophosphonium hexa Fluorophosphide salt (Bop reagent) and the like.
Moreover, you may use an acid as needed. As the acid, those usually used in dehydration condensation and the like can be used. Specifically, inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p- Organic acids such as toluenesulfonic acid can be mentioned. These may be used alone or in combination of two or more.
About 2-5 equivalent times is preferable with respect to compound (I-01), and, as for the addition amount of a compound (I-02), 2-3 equivalent times is more preferable.
The reaction temperature is preferably -20 to 40 ° C, more preferably 0 to 30 ° C.
The reaction time varies depending on the reactivity of the compound (I-01) and the compound (I-02), the reaction temperature, and the like, but usually 0.5 to 24 hours are preferable, and 1 to 12 hours are more preferable.
The structure of the obtained compound (I) is as follows: ¹ H-nuclear magnetic resonance (NMR) spectrum method, ¹³ C-NMR spectrum method, ¹⁹ F-NMR spectrum method, infrared absorption (IR) spectrum method, mass spectrometry (MS) It can be confirmed by a general organic analysis method such as a method, an elemental analysis method or an X-ray crystal diffraction method.

The compound (I) of the present invention described above is a novel compound that has not been known so far.
The compound (I) of the present invention is useful as a radical polymerization initiator. By using a radical polymerization initiator composed of the compound (I), the following general formula (i-1) is added to at least one terminal of the main chain. The polymer which has group represented by these can be manufactured.

［式中、Ｒ^１、Ｒ^２はそれぞれ前記と同じである。］

[Wherein, R ¹ and R ² are the same as defined above. ]

≪Radical polymerization initiator≫
The radical polymerization initiator according to the third aspect of the present invention comprises the compound (I) according to the second aspect.
The radical polymerization initiator of the present invention can be used for the production of any polymer conventionally produced by radical polymerization. The radical polymerization initiator is particularly useful for the production of a polymer used by blending with a resist composition, and the resist composition containing a polymer produced using the radical polymerization initiator is a liquid. Suitable for immersion exposure.
The monomer to be radically polymerized by the radical polymerization initiator may be any one that can be radically polymerized, and is appropriately selected according to the polymer to be produced. The monomer to be polymerized by the radical polymerization initiator of the present invention is preferably a vinyl monomer, more preferably an acrylate monomer and / or a styrene monomer, and particularly an acrylate monomer. The body is preferred. Examples of the acrylate monomer include monomers that induce structural units (a1) to (a3), (c1-1) and the like described later.

≪Polymer≫
The polymer of the first aspect of the present invention is a polymer having a group represented by the general formula (i-1) (hereinafter referred to as a terminal group (i-1)) at at least one terminal of the main chain. It is.
In formula (i-1), R ¹ and R ² are the same as R ¹ and R ^{2 in} formula (I), respectively.
Since the polymer of the present invention has a terminal group (i-1), it has a property of increasing hydrophilicity by the action of an alkali developer and improving affinity for the alkali developer.
That is, in the terminal group (i-1), by having R ² , the carbon atom of the carbonyl group (C═O) in the structure and the carbon atom in the structure when contacted with an alkali developer, as described above, The bond between the oxygen atom (—O—) bonded to the carbon atom can be broken. Therefore, when the polymer of the present invention is brought into contact with an alkali developer, by hydrolysis, a carbonyl group in the terminal group (i-1) at the end of the main chain and an -oxygen atom bonded to a carbon atom of the carbonyl group ( The bond with -O-) is broken, and -O-R ² is dissociated, and at the same time, a carbonyl group, which is a hydrophilic group, is formed.

The polymer of the present invention only needs to have a terminal group (i-1) at at least one end of the main chain, and other constitutions (for example, constitutional units constituting the polymer) are the same as those of the polymer. A known product can be used depending on the application.
The polymer of the present invention is useful for a resist composition, and the resist composition containing the polymer of the present invention is suitable for immersion exposure.
The resist composition to which the polymer of the present invention is blended is not particularly limited, but includes a base material component whose solubility in an alkali developer is changed by the action of an acid, and an acid generator component that generates an acid upon exposure. A chemically amplified resist composition is preferable.
The polymer of the present invention is particularly useful as a base component of a chemically amplified resist composition or as an additive component arbitrarily blended in the resist composition.
Regarding the constitution of the polymer used in these applications, the (A1) component of the resist composition of the fifth aspect of the present invention and the (C) of the resist composition of the sixth aspect of the present invention are described in detail below, respectively. ') Explain with ingredients.

As a method for producing the polymer of the present invention having the terminal group (i-1) at at least one end of the main chain, a desired monomer is polymerized by radical polymerization using the radical polymerization initiator of the present invention. The method is preferred. That is, the polymer of the present invention is preferably a radical polymer obtained by radical polymerization using the radical polymerization initiator of the present invention. In particular, when the radical polymerization initiator of the present invention contains an electron-withdrawing group such as a fluorine atom in the terminal portion (R ² ), the electron-withdrawing property is improved and the azo bond in the molecule is easily opened, thereby yielding. Which can be polymerized at low temperatures.
The monomer to be radically polymerized is not particularly limited as long as it can be radically polymerized, and a monomer for deriving a structural unit constituting the polymer is appropriately selected according to the polymer to be produced.
The radical polymerization can be carried out using a known method except that the radical polymerization initiator of the present invention is used as a radical polymerization initiator.
In radical polymerization, the radical polymerization initiator of the present invention may be used alone or in combination of two or more.

Further, as another method for producing the polymer of the present invention, a compound (I-01) represented by the following general formula (I-01) is used as a radical polymerization initiator, so that at least one end of the main chain is present. A polymer (precursor polymer) having a group represented by the following general formula (ii-1) is obtained, and R ² [R ² is the same as above] in the carboxy group at the terminal of the main chain of the precursor polymer. . ] (In which the hydrogen atom at the terminal of the carboxy group is substituted with R ² ).
As compound (I-01), known compounds can be used.
Introduction of R ² can be performed using a conventionally known method, for example, by reacting a precursor polymer with a compound (I-02) represented by the following general formula (I-02). Can be implemented. The reaction can be carried out in the same manner as described in the method for producing compound (I).

［式中、Ｒ^１、Ｒ^２はそれぞれ前記と同じである。］

[Wherein, R ¹ and R ² are the same as defined above. ]

≪Resist composition≫
The resist composition of the fourth aspect of the present invention contains the polymer of the present invention.
A resist film formed using such a resist composition has a high hydrophobicity at the time of immersion exposure by containing the polymer of the present invention, and is subjected to various treatments after immersion exposure (PEB treatment, alkali development, etc.). It has the property of increasing hydrophilicity (decreasing hydrophobicity).
That is, first, the polymer of the present invention has a structure in which a base dissociable group (—O—R ² ) dissociated by the action of an alkali developer is bonded to a carbonyl group at the end of the main chain as described above. . Therefore, when an alkali developer is brought into contact with the resist film, the polymer of the present invention is hydrolyzed by the action of the alkali developer, and —O—R ² is dissociated to form a carboxy group. As a result, the resist The hydrophilicity of the membrane is improved.
Therefore, the resist film has higher hydrophobicity at the time of exposure and lowering of the hydrophobicity (improving hydrophilicity) at the time of alkali development as compared with the case where the polymer of the present invention is not included. . Such a property is particularly prominent when R ² is a highly hydrophobic group such as a hydrocarbon group having an electron-withdrawing group, particularly a hydrocarbon group having a fluorine atom.
The resist film with improved hydrophobicity at the time of exposure is very excellent in water followability required when immersion exposure is performed using a scanning immersion exposure machine as described in Non-Patent Document 1. ing.
Further, in the prior art, if the resist film is highly hydrophobic, the surface of the resist pattern after development is defective (for example, a watermark defect due to the influence of an immersion medium such as water or an alkaline developer, and other bridge defects or defective openings). However, since the hydrophilicity of the resist film formed using the resist composition of the present invention increases after immersion exposure, the occurrence of the defect can be reduced. The above problem is particularly significant in the case of a positive resist composition in which a resist film in an unexposed portion remains without being removed, and the present invention is particularly effective in the case of a positive type.
Therefore, the resist composition of the present invention has good lithography characteristics, which are characteristics required for a resist composition used for immersion exposure, and characteristics (hydrophobicity) suitable for immersion exposure. It is suitable as a resist composition for immersion exposure.

The resist composition of the present invention may be a positive type or a negative type. A positive type is preferred.
Further, the resist composition of the present invention may be a non-chemical amplification type or a chemical amplification type. In the present invention, a chemically amplified resist composition is particularly preferable because a resist pattern can be formed with high sensitivity and high resolution.
The chemically amplified resist composition generally contains a base material component whose solubility in an alkaline developer is changed by the action of an acid and an acid generator component that generates an acid upon exposure. When this resist composition is exposed to light, an acid is generated from the acid generator component, and the solubility of the base component in an alkaline developer is changed by the action of the acid. Therefore, in the formation of a resist pattern, when the resist film formed using the resist composition is selectively exposed, the solubility of the exposed portion in the alkaline developer changes (in the case of a positive type, an increase in the case of a negative type) On the other hand, since the solubility of the unexposed area in the alkaline developer does not change, the resist pattern is formed by alkali development.
Preferred embodiments when the resist composition of the present invention is a chemically amplified resist composition include the resist composition of the fifth aspect and the resist composition of the sixth aspect of the present invention.
Resist composition of the fifth aspect: base material component (A) whose solubility in an alkaline developer is changed by the action of an acid (hereinafter referred to as component (A)), and an acid generator component that generates an acid upon exposure (B) (hereinafter referred to as component (B)), a chemically amplified resist composition, wherein the component (A) is a base material component (A1) (hereinafter referred to as ( A1) a resist composition containing a component)).
Resist composition of the sixth aspect: base material component (A ′) whose solubility in an alkaline developer is changed by the action of an acid (hereinafter referred to as (A ′) component), an acid generator that generates an acid upon exposure A resist composition containing a component (B ′) (hereinafter referred to as (B ′) component) and an additive component (C ′) (hereinafter referred to as (C ′) component) comprising the polymer of the present invention.

[Resist Composition of Fifth Aspect]
<(A) component>
The “base material component” is an organic compound having a film forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and a nano-level resist pattern is easily formed.
The organic compound having a molecular weight of 500 or more includes a low molecular weight organic compound having a molecular weight of 500 or more and 2,000 or less (hereinafter referred to as a low molecular compound) and a high molecular weight organic compound having a molecular weight of 2,000 or more (hereinafter referred to as a polymer compound). )). As the low molecular weight compound, a non-polymer is usually used. A polymer is used as the polymer compound. In the case of a polymer, the weight average molecular weight in terms of polystyrene by GPC (gel permeation chromatography) is used as the “molecular weight”. Hereinafter, a polymer having a molecular weight greater than 2000 is referred to as “resin”.

When the resist composition of the present invention is a negative resist composition, as the component (A), a base component soluble in an alkali developer is used, and a crosslinking agent is further blended.
In such a negative resist composition, when an acid is generated from the component (B) by exposure, the acid acts to cause crosslinking between the base component and the crosslinking agent, and the base component is in contact with the alkaline developer. Changes to slightly soluble. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the negative resist composition on the substrate is selectively exposed, the exposed portion turns into poorly soluble in an alkaline developer, while unexposed. Since the portion remains soluble in the alkali developer and does not change, a resist pattern can be formed by alkali development.
As the crosslinking agent, for example, it is usually preferable to use an amino crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group because a good resist pattern with less swelling can be formed. It is preferable that the compounding quantity of a crosslinking agent is 1-50 mass parts with respect to 100 mass parts of alkali-soluble resin.
When the resist composition of the present invention is a positive resist composition, as the component (A), a base material component whose solubility in an alkaline developer is increased by the action of an acid is used. The component (A) is hardly soluble in an alkali developer before exposure, and when an acid is generated from the component (B) by exposure, the solubility in the alkali developer is increased by the action of the acid. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the positive resist composition on the substrate is selectively exposed, the exposed portion changes from poorly soluble to soluble in an alkaline developer. On the other hand, since the unexposed portion remains hardly soluble in alkali and does not change, a resist pattern can be formed by alkali development.
The resist composition of the present invention is preferably a positive resist composition. That is, in the resist composition of the present invention, the component (A) is preferably a base material component whose solubility in an alkaline developer is increased by the action of an acid.

In this invention, (A) component contains (A1) component which consists of a polymer of this invention.
The component (A1) may be any component having the terminal group (i-1) at least at one end of the main chain, and the configuration other than the terminal portion has been conventionally a group for a chemically amplified resist. It may be the same as the resin (base resin) used as the material component, and among those proposed as base resins such as chemically amplified KrF positive resist compositions and ArF positive resist compositions. From the above, it can be appropriately selected according to the type of exposure light source used in forming the resist pattern.
As the base resin of the negative resist composition, a resin that is soluble in an alkali developer (hereinafter referred to as an alkali-soluble resin) is usually used.
As the alkali-soluble resin, a resin having a unit derived from at least one selected from α- (hydroxyalkyl) acrylic acid or a lower alkyl ester of α- (hydroxyalkyl) acrylic acid is a good resist with little swelling. A pattern can be formed, which is preferable. Α- (Hydroxyalkyl) acrylic acid includes acrylic acid in which a hydrogen atom is bonded to the α-position carbon atom to which the carboxy group is bonded, and a hydroxyalkyl group (preferably having 1 carbon atom) in the α-position carbon atom. One or both of [alpha] -hydroxyalkylacrylic acids to which (5) hydroxyalkyl groups) are attached.

Specific examples of the base resin in the positive resist composition include those obtained by protecting the hydrophilic group of a resin having a hydrophilic group (hydroxyl group, carboxy group, etc.) with an acid dissociable, dissolution inhibiting group.
Examples of the resin having a hydrophilic group include a novolak resin, a resin having a structural unit derived from hydroxystyrene (PHS resin), and a resin having a structural unit derived from an acrylate ester (acrylic resin). It is done. Any of these may be used alone or in combination of two or more.
In the present specification and claims, the “structural unit derived from hydroxystyrene” is a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene or α-lower alkylhydroxystyrene. “Α-lower alkylhydroxystyrene” indicates that the lower alkyl group is bonded to the carbon atom to which the phenyl group is bonded.
Examples of the PHS resin include polyhydroxystyrene (PHS) and hydroxystyrene-styrene copolymer.
The “structural unit derived from an acrylate ester” means a structural unit constituted by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include not only acrylic acid esters in which a hydrogen atom is bonded to the α-position carbon atom, but also those in which a substituent (an atom or group other than a hydrogen atom) is bonded to the α-position carbon atom. Include concepts. Examples of the substituent include a lower alkyl group and a halogenated lower alkyl group. The α-position (α-position carbon atom) of a structural unit derived from an acrylate ester means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
The lower alkyl group is an alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group. And a lower linear or branched alkyl group such as a neopentyl group.
Specific examples of the halogenated lower alkyl group include groups in which some or all of the hydrogen atoms of the lower alkyl group 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.
In the structural unit derived from an acrylate ester, the α-position of the acrylate ester is preferably a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and a hydrogen atom, a lower alkyl group or A fluorinated lower alkyl group is more preferable, and a hydrogen atom or a methyl group is most preferable in terms of industrial availability.

In the present invention, the polymer used as the component (A1) preferably has a structural unit derived from an acrylate ester.
In particular, the polymer preferably has a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group (hereinafter referred to as structural unit (a1)).
In addition to the structural unit (a1), the polymer preferably further has a structural unit derived from an acrylate ester containing a lactone-containing cyclic group (hereinafter referred to as the structural unit (a2)). .
In addition to the structural unit (a1), or in addition to the structural units (a1) and (a2), the polymer further includes a structure derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. It is preferable to have a unit (hereinafter referred to as a structural unit (a3)).
Moreover, this polymer may have other structural units (henceforth a structural unit (a4)) other than the said structural units (a1)-(a3).

-Structural unit (a1):
The structural unit (a1) is a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and dissociates with an acid. This increases the solubility of the entire component in an alkaline developer. The acid dissociable, dissolution inhibiting group is not particularly limited, and those that have been proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position.
The “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O) —O—). ), The tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom. In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom. The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.

Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.
“Aliphatic branched” means having a branched structure having no aromaticity. The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic branched acid dissociable, dissolution inhibiting group include a group represented by -C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically, a tert-butyl group or a 2-methyl-2-butyl group. 2-methyl-2-pentyl group, 3-methyl-3-pentyl group, and the like. A tert-butyl group is particularly preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
In the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group, the aliphatic cyclic group may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
The aliphatic cyclic group may be a hydrocarbon group (alicyclic group) composed of carbon and hydrogen, and some of the carbon atoms constituting the ring of the alicyclic group are oxygen atoms, nitrogen atoms, sulfur. It may be a heterocyclic group substituted with a heteroatom such as an atom. As the aliphatic cyclic group, an alicyclic group is preferable.
The aliphatic cyclic group may be either saturated or unsaturated, but is preferably saturated because it is highly transparent to ArF excimer laser and the like, and has excellent resolution and depth of focus (DOF). .
It is preferable that carbon number of an aliphatic cyclic group is 5-15.
Specific examples of the monocyclic alicyclic group include groups in which one or more hydrogen atoms have been removed from cycloalkane. More specifically, a group in which one or more hydrogen atoms have been removed from cyclopentane or cyclohexane can be mentioned, and a group in which two hydrogen atoms have been removed from cyclohexane is preferred.
Specific examples of the polycyclic alicyclic group include groups in which one or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, or the like. More specifically, a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane can be used. Of these, groups in which two hydrogen atoms have been removed from adamantane, norbornane, and tetracyclododecane are preferred because they are easily available in the industry. Of these, a group in which two hydrogen atoms have been removed from adamantane or norbornane is preferable.

Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include: (i) a group having a tertiary carbon atom on the ring skeleton of the aliphatic cyclic group; (ii) an aliphatic cyclic group; And a group having a branched alkylene group having a tertiary carbon atom bonded thereto.
Specific examples of (i) include groups represented by the following general formulas (1-1) to (1-9).
Specific examples of (ii) include groups represented by the following general formulas (2-1) to (2-6).

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

^{Wherein, R 14} represents an alkyl group, g is an integer of 0-8. ]

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立にアルキル基である。］

[Wherein, R ¹⁵ and R ¹⁶ each independently represents an alkyl group. ]

As the alkyl group for R ^{14 to} R ¹⁶ , a lower alkyl group is preferable, and a linear or branched alkyl group is preferable. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. Among these, a methyl group, an ethyl group or an n-butyl group is preferable, and a methyl group or an ethyl group is more preferable.

In formula (1-2), g is preferably an integer of 0 to 5, more preferably an integer of 1 to 3, and even more preferably 1 or 2.
Specific examples of the acid dissociable, dissolution inhibiting group represented by the formula (1-2) include, for example, 1-methyl-1-cyclobutyl group, 1-ethyl-1-cyclobutyl group, 1-isopropyl-1-cyclobutyl group. 1-methyl-1-cyclopentyl group, 1-ethyl-1-cyclopentyl group, 1-isopropyl-1-cyclopentyl group, 1-methyl-1-cyclohexyl group, 1-ethyl-1-cyclohexyl group, 1-isopropyl- 1-cyclohexyl group, 1-methyl-1-cycloheptyl group, 1-ethyl-1-cycloheptyl group, 1-isopropyl-1-cycloheptyl group, 1-methyl-1-cyclooctyl group, 1-ethyl-1 -A cyclooctyl group etc. are mentioned.

The “acetal-type acid dissociable, dissolution inhibiting group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an alkali-soluble group such as a carboxy group or a hydroxyl group. When an acid is generated by exposure, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

［式中、Ｙは直鎖状もしくは分岐鎖状のアルキル基または脂肪族環式基であり、ｎは０〜３の整数であり、Ｒ^１’およびＲ^２’はそれぞれ独立して直鎖状もしくは分岐鎖状のアルキル基または水素原子であり、ＹおよびＲ^１’が相互に結合して脂肪族環式基を形成していてもよい。］

[Wherein Y is a linear or branched alkyl group or aliphatic cyclic group, n is an integer of 0 to 3, and R ¹ ′ and R ² ′ are each independently a linear group] Or it is a branched alkyl group or a hydrogen atom, and Y and R ¹ ′ may be bonded to each other to form an aliphatic cyclic group. ]

In the above formula (p1), Y represents a linear or branched alkyl group or an aliphatic cyclic group.
When Y is linear or branched, it preferably has 1 to 15 carbon atoms, more preferably 1 to 5, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When Y is an aliphatic cyclic group, the aliphatic cyclic group is appropriately selected from monocyclic or polycyclic aliphatic cyclic groups that have been proposed in large numbers in ArF resists and the like. Examples thereof include those similar to the above “aliphatic cyclic group”.
The aliphatic cyclic group for Y preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.

In formula (p1), n is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
R ¹ ′ and R ² ′ are each independently a linear or branched alkyl group or a hydrogen atom.
The linear or branched alkyl group for R ¹ ′ and R ² ′ is preferably a lower alkyl group. Examples of the lower alkyl group include the same lower alkyl groups as those described above for R, and are preferably a methyl group or an ethyl group, and most preferably a methyl group.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the group represented by the formula (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

[Wherein R ¹ ′, n and Y are the same as described above. ]

In the formula (p1), Y and R ¹ ′ may be bonded to each other to form an aliphatic cyclic group.
In this case, an aliphatic cyclic group is formed by Y, R ¹ ′, —O— (CH ₂ ) _n —, and the carbon atom to which R ² ′ is bonded. As this aliphatic cyclic group, a 4-7 membered ring is preferable and a 4-6 membered ring is more preferable. Specific examples of the aliphatic cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  As the structural unit (a1), one or more selected from the group consisting of structural units represented by the following general formula (a1-0-1) and structural units represented by the following general formula (a1-0-2): Is preferably used.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^１は酸解離性溶解抑制基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^２は酸解離性溶解抑制基を示し；Ｙ^２は２価の連結基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X ² represents an acid dissociable, dissolution inhibiting group; Y ² represents a divalent linking group. ]

In general formula (a1-0-1), the lower alkyl group or halogenated lower alkyl group for R is the same as the lower alkyl group or halogenated lower alkyl group that may be bonded to the α-position of the acrylate ester. .
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).
The divalent linking group for Y ² is preferably an alkylene group, a divalent aliphatic cyclic group or a divalent linking group containing a hetero atom.
When Y ² is an alkylene group, it is preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Most preferably it is.
When Y ² is a divalent aliphatic cyclic group, the aliphatic cyclic group may be monocyclic or polycyclic.
The aliphatic cyclic group may be saturated or unsaturated, but is preferably saturated. Further, it may be a hydrocarbon group consisting of only carbon atoms and hydrogen atoms, and may have other atoms (hetero atoms such as oxygen atom, nitrogen atom, sulfur atom), but is a hydrocarbon group. It is preferable.
The aliphatic cyclic group preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms.
Specifically, the aliphatic cyclic group is a group obtained by removing two or more hydrogen atoms from a monocycloalkane; two or more hydrogen atoms from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. And the group except for. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. The aliphatic cyclic group is particularly preferably a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane or tetracyclododecane.
A substituent may be bonded to the aliphatic cyclic group. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

When Y ² is a divalent linking group containing a hetero atom, examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, —C (═O) —NH—, —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—, a group represented by the formula —A—O—B—, a formula — [A—C (═O) —O] _m —. Examples thereof include a group represented by B-. Here, A and B are each independently a divalent hydrocarbon group which may have a substituent, and m is an integer of 0 to 3.
When Y ² is —NH—, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. It is particularly preferred that
When Y ² is —A—O—B— or — [A—C (═O) —O] _m —B—, A and B may each independently have a substituent. It is a divalent hydrocarbon group.
m is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 1.

The hydrocarbon group in A may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group for A may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group for A include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in the structure.
The “linear or branched aliphatic hydrocarbon group” in A preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 5, and particularly preferably 1 or 2. preferable.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group, an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [— (CH ₂ ) ₃ -], tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and 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 -, - 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 - , etc. Alkyltrimethylene group of —CH (CH ₃ ) CH ₂ CH ₂ CH ₂ —, —CH _{2 CH (CH 3) CH 2} CH 2 - alkyl alkylene group such as an alkyl tetramethylene group such like. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

As the “aliphatic hydrocarbon group including a ring in the structure” in A, a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), the cyclic aliphatic hydrocarbon group Includes a group bonded to the terminal of the chain aliphatic hydrocarbon group described above or interposed in the middle of the chain aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

  As A, 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. The ethylene group is most preferred.

Examples of the hydrocarbon group for B include the same divalent hydrocarbon groups as those described above for A.
B is preferably a linear or branched aliphatic hydrocarbon group, particularly preferably a methylene group, an ethylene group or an alkylmethylene group.
The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

In the group represented by the formula — [A—C (═O) —O] _m —B—, m is an integer of 0 to 3, preferably an integer of 0 to 2, and 0 or 1 Is more preferable and 1 is most preferable.

In the present invention, the divalent linking group for Y ² is preferably a divalent group containing a hetero atom, and particularly preferably a linear group having an oxygen atom as a hetero atom, such as a group containing an ester bond.
Among them, a group represented by the above-described —A—O—B— or —A—C (═O) —O—B— is preferable, and in particular, — (CH ₂ ) _a —C (═O) —O— ( CH _{2) b} - group is particularly desirable.
a is an integer of 1 to 5, preferably 1 or 2, and most preferably 2.
b is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.

  More specifically, examples of the structural unit (a1) include structural units represented by the following general formulas (a1-1) to (a1-4).

［式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５の低級アルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表し；Ｙ^２はアルキレン基、２価の脂肪族環式基又は「Ａ−Ｏ−Ｂ」（ただし、Ａ、Ｂは前記と同じである。）を表し；Ｒは前記と同じであり、Ｒ^１’、Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５の低級アルキル基を表す。］

[Wherein, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a lower alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; n represents an integer of 0 to 3] Y ² represents an alkylene group, a divalent aliphatic cyclic group or “A-O-B” (where A and B are as defined above); R is as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. ]

In the formula, X 'include the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1) ', R 2'} , n, Y The same thing is mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).
Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among these, the structural unit represented by general formula (a1-1) or (a1-3) is preferable, and specifically, (a1-1-1) to (a1-1-7), (a1-1-1-) It is more preferable to use at least one selected from the group consisting of 36) to (a1-1-42) and (a1-3-49) to (a1-3-56).
Furthermore, as the structural unit (a1), those represented by the following general formula (a1-1-01) including the structural units of formula (a1-1-1) to formula (a1-1-5), What is represented by the following general formula (a1-1-02) including the structural units of formulas (a1-1-36) to (a1-1-42), formulas (a1-3-49) to (a1- 3-52) represented by the following general formula (a1-3-01) including the structural units, or the following structural units of the formulas (a1-3-53) to (a1-3-56) What is represented by general formula (a1-3-02) is also preferable.

（式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１１は低級アルキル基を示す。）

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹¹ represents a lower alkyl group.)

（式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１２は低級アルキル基を示す。ｈは１〜３の整数を表す）

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ¹² represents a lower alkyl group, and h represents an integer of 1 to 3)

In general formula (a1-1-01), R is the same as defined above. The lower alkyl group for R ^{11 is the same as} the lower alkyl group for R, and is preferably a methyl group or an ethyl group.
In general formula (a1-1-02), R is the same as defined above. The lower alkyl group for R ^{12 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group. h is preferably 1 or 2, and most preferably 2.

（式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｒ^１４は低級アルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数である。）

Wherein R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹⁴ represents a lower alkyl group, R ¹³ represents a hydrogen atom or a methyl group, and a represents an integer of 1 to 10. .)

（式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｒ^１４は低級アルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数であり、ｎ’は０〜３の整数である。）

Wherein R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹⁴ represents a lower alkyl group, R ¹³ represents a hydrogen atom or a methyl group, and a represents an integer of 1 to 10. , N ′ is an integer of 0 to 3.)

In the general formula (a1-3-01) or (a1-3-02), R is the same as described above.
R ¹³ is preferably a hydrogen atom.
The lower alkyl group for R ^{14 is the same as} the lower alkyl group for R, and is preferably a methyl group or an ethyl group.
a is preferably an integer of 1 to 8, more preferably an integer of 2 to 5, and most preferably 2.

  In the component (A1), the proportion of the structural unit (a1) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, more preferably 25 to 50 mol%, based on all structural units constituting the component (A1). Is more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

Structural unit (a2):
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group. When it has another ring structure, it is called a polycyclic group regardless of the structure.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.
As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, examples of the lactone-containing monocyclic group include groups in which one hydrogen atom has been removed from γ-butyrolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり、Ｒ’は水素原子、低級アルキル基、炭素数１〜５のアルコキシ基または−ＣＯＯＲ”であり、前記Ｒ”は水素原子、または炭素数１〜１５の直鎖状、分岐鎖状もしくは環状のアルキル基であり、ｍは０または１の整数であり、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る。］

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ′ is a hydrogen atom, a lower alkyl group, an alkoxy group having 1 to 5 carbon atoms, or —COOR ″, and the above R ″ is A hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms, m is an integer of 0 or 1, and A ″ is a carbon which may contain an oxygen atom or a sulfur atom. It is an alkylene group of formula 1 to 5, an oxygen atom or a sulfur atom.]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
The lower alkyl group for R ′ is the same as the lower alkyl group for R in the structural unit (a1).
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom or fluorine atom A group obtained by removing one or more hydrogen atoms from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group. Specific examples thereof include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Can be mentioned.
In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Specific examples of the alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or sulfur atom of A ″ include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, —O—CH ₂ —. _{, -CH 2 -O-CH 2 -} , - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
Below, the specific structural unit of the said general formula (a2-1)-(a2-5) is illustrated.

In the component (A1), as the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
As the structural unit (a2), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formulas (a2-1) to ( At least one selected from the group consisting of structural units represented by a2-3) is more preferred. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-2-9), (a2-2-10) ), (A2-3-1), (a2-3-2), (a2-3-9) and (a2-3-10) at least one selected from the group consisting of structural units It is preferable to use it.

  The proportion of the structural unit (a2) in the component (A1) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, with respect to the total of all structural units constituting the component (A1). 50 mol% is more preferable. By making it the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by making it the upper limit value or less, it is possible to balance with other structural units.

-Structural unit (a3):
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.
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. 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 polycyclic aliphatic hydrocarbon group (polycyclic group). It is done. As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. The polycyclic group 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 preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

  The structural unit (a3) is derived from a hydroxyethyl ester of acrylic acid when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms. When the hydrocarbon group is a polycyclic group, a structural unit represented by the following formula (a3-1), a structural unit represented by (a3-2), (a3-3) ) Is preferable.

（式中、Ｒは前記に同じであり、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 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 l is an integer of 1 to 5) And s is an integer of 1 to 3.)

In 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 3rd and 5th 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, and a hydroxyl group bonded to the 3-position of the adamantyl group is particularly preferred.
In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.
In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
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 all structural units constituting the component (A1). More preferred is ˜25 mol%.

-Structural unit (a4):
The component (A1) may contain other structural units (a4) other than the structural units (a1) to (a3) as long as the effects of the present invention are not impaired.
The structural unit (a4) is not particularly limited as long as it is another structural unit that is not classified into the structural units (a1) to (a3) described above, and is for ArF excimer laser and KrF excimer laser (preferably ArF excimer). A number of hitherto known materials can be used for resist resins such as lasers.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing an acid non-dissociable aliphatic polycyclic group (hereinafter referred to as a structural unit (a4 ′)), or a structural unit derived from acrylic acid. A structural unit derived from hydroxystyrene, a structural unit derived from styrene, a structural unit (c1) described later, and the like. Among these, the structural unit (a4 ′) is preferable.

Examples of the aliphatic polycyclic group in the structural unit (a4 ′) include those similar to those exemplified in the case of the structural unit (a1). For ArF excimer laser, KrF excimer laser A number of hitherto known materials can be used as the resin component of the resist composition such as for use (preferably for ArF excimer laser). In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, a tetracyclododecanyl 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 structures having the following general formulas (a4-1) to (a4-5).

（式中、Ｒは前記と同じである。）

(In the formula, R is as defined above.)

  When the structural unit (a4 ′) is contained in the component (A1), the structural unit (a4 ′) is contained in an amount of 1 to 30 mol% based on the total of all the structural units constituting the component (A1). Is preferable, and it is more preferable to make it contain 10-20 mol%.

The component (A1) is preferably a copolymer having the structural units (a1), (a2) and (a3). Examples of such a copolymer include a copolymer composed of the structural units (a1), (a2) and (a3), and a copolymer composed of the structural units (a1), (a2), (a3) and (a4). A polymer etc. can be illustrated.
In the component (A), as the component (A1), one type may be used alone, or two or more types may be used in combination.

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 100,000, more preferably 3000 to 80000, and more preferably 5000 to 50000. Most preferred. When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and when it is larger than the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.
The component (A) is obtained, for example, by polymerizing a monomer that derives each structural unit constituting the component (A) by radical polymerization using the radical polymerization initiator of the present invention as described above. be able to.
As the monomer for deriving each structural unit, it may be synthesized or commercially available.

In the resist composition of the fifth aspect of the present invention, the solubility in an alkaline developer is changed by the action of an acid other than the component (A1) as the component (A) as long as the effects of the present invention are not impaired. "Substrate component" (hereinafter referred to as component (A2)) may be contained.
The component (A2) is not particularly limited, and those conventionally used as base material components for chemically amplified resists can be used.

<(B) component>
The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.
As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基またはアルキル基を表し；式（ｂ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２つが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く；Ｒ^４”は、直鎖状、分岐鎖状または環状のアルキル基またはフッ素化アルキル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; among R ¹ ″ to R ³ ″ in formula (b-1), Any two may be bonded together to form a ring with the sulfur atom in the formula; R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group; R ¹ At least one of “˜R ³ ” represents an aryl group, and at least one of “R ⁵ ″ to R ⁶ ” represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. In addition, any two of R ¹ ″ to R ³ ″ in formula (b-1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
Further, at least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all of R ¹ ″ to R ³ ″ are aryl groups.
The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl or alkoxy. It may or may not be substituted with a group, a halogen atom, a hydroxyl group or the like. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, 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, Most preferred is a tert-butoxy group.
The alkoxy group that may be substituted with a hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may substitute the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
Among these, R ¹ ″ to R ³ ″ are most preferably a phenyl group or a naphthyl group, respectively.

When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, a 3 to 10 membered ring including the sulfur atom is formed. It is preferable that a 5- to 7-membered ring is formed.
When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one may be an aryl group preferable. Examples of the aryl group are the same as the aryl groups of R ¹ ″ to R ³ ″.

R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group is a cyclic group as indicated by R ¹ ″ and preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and more preferably 6 carbon atoms. Most preferably, it is -10.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms. The fluorination rate of the fluorinated alkyl group (ratio of fluorine atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%. Particularly, all the hydrogen atoms are substituted with fluorine atoms. A fluorinated alkyl group (perfluoroalkyl group) is preferable because the strength of the acid is increased.
R ⁴ ″ is most preferably a linear or cyclic alkyl group or a fluorinated alkyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"As ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

Specific examples of the onium salt acid generators represented by the formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, tri (4-methylphenyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or the same Nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate , Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.
In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

  In addition, in the general formula (b-1) or (b-2), an onium salt-based acid generator in which the anion moiety is replaced with an anion moiety represented by the following general formula (b-3) or (b-4). Can also be used (the cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

  Moreover, the sulfonium salt which has a cation part represented by the following general formula (b-5) or (b-6) can also be used as an onium salt type | system | group acid generator.

［式中、Ｒ^４１〜Ｒ^４６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_１〜ｎ_５はそれぞれ独立して０〜３の整数であり、ｎ_６は０〜２の整数である。］

[Wherein R ^{41 to} R ⁴⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{1 to} n ₅ are each independently an integer of 0 to 3; There, _{n 6} is an integer of 0-2. ]

In R ^{41 to} R ⁴⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{41 to} R ⁴⁶ are integers of 2 or more, the plurality of R ^{41 to} R ⁴⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ^{4 ″} SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). An anion moiety represented by the above general formula (b-3) or (b-4), etc. Among these, a fluorinated alkylsulfonic acid ion is preferable, and a fluorinated alkylsulfonic acid having 1 to 4 carbon atoms. Ion is more preferable, and linear perfluoroalkylsulfonic acid ions having 1 to 4 carbon atoms are particularly preferable, and specific examples thereof include trifluoromethylsulfonic acid ions, heptafluoro-n-propylsulfonic acid ions, and nonafluoro-n. -Butyl sulfonate ion etc. are mentioned.

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. is there. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

(In formula (B-1), R ³¹ and R ³² each independently represents an organic group.)

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ^31, a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with 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. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.

As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ”は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3.]

In the general formula (B-2), alkyl or halogenated alkyl group having no substituent group for R ³³ preferably has 1 to 10 carbon atoms, 1 to 8 carbon atoms, more preferably, carbon Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.

As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.

The alkyl group or halogenated alkyl group having no substituent of R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups having no substituent as R ³⁵ described above.
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Also, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO 2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, it is particularly preferable to use an onium salt having a fluorinated alkyl sulfonate ion as an anion as the component (B).
The content of the component (B) in the resist composition is preferably 0.5 to 30 parts by mass, more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the component (A). By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Optional component>
The resist composition according to the fifth aspect of the present invention contains, as an optional component, a nitrogen-containing organic compound (D) (hereinafter referred to as (D)) for the purpose of improving the resist pattern shape, the stability over time and the like. Component)).
As the component (D), a wide variety of components have already been proposed, and any known one may be used. Among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are used. preferable. Here, the aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 20 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 hydroxyalkyl group having 20 or less carbon atoms. .
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, and the like; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amine, tri -n- octanol amine, stearyl diethanolamine, alkyl alcohol amines such as lauryl diethanolamine. Among these, trialkylamine and / or alkyl alcohol amine are preferable.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
Examples of the aromatic amine include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, and tribenzylamine.
Other aliphatic amines include tris (2-methoxymethoxyethyl) amine, tris {2- (2-methoxyethoxy) ethyl} amine, tris {2- (2-methoxyethoxymethoxy) ethyl} amine, tris {2 -(1-methoxyethoxy) ethyl} amine, tris {2- (1-ethoxyethoxy) ethyl} amine, tris {2- (1-ethoxypropoxy) ethyl} amine, tris [2- {2- (2-hydroxy Ethoxy) ethoxy} ethylamine and the like.
These may be used alone or in combination of two or more.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

The resist composition according to the fifth aspect of the present invention includes an organic carboxylic acid and a phosphorus oxoacid and its oxoacid as optional components for the purpose of preventing sensitivity deterioration, improving the resist pattern shape, stability over time, etc. You may contain the at least 1 sort (s) of compounds (E) (henceforth (E) component) selected from the group which consists of a derivative | guide_body.
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 phosphorus oxo acids and derivatives thereof include phosphoric acid, phosphonic acid, phosphinic acid and the like, and among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
As the component (E), an organic carboxylic acid is preferable, and salicylic acid is particularly preferable.
(E) A component is normally used in the ratio of 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

  The resist composition according to the fifth aspect of the present invention further contains, as desired, miscible additives, for example, an additional resin for improving the performance of the resist film, a surfactant for improving the coating property, and dissolution. An inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

The resist composition according to the fifth aspect of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can 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 can 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, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone;
Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol;
Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl ether, monopropyl of the polyhydric alcohols or the compound having an ester bond Derivatives of polyhydric alcohols such as ethers, monoalkyl ethers such as monobutyl ether or compounds having an ether bond such as monophenyl ether [in these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) Is preferred];
Cyclic ethers such as dioxane and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate;
Anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene and other aromatic organic solvents, dimethyl sulfoxide (DMSO).
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Of these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA or PGME, and the polar solvent is preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA or PGME and a polar solvent, and is preferably 1: 9 to 9: 1, more preferably 2: 8 to The range is 8: 2.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 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.
Furthermore, a mixed solvent of PGME and dimethyl sulfoxide is also preferable. In this case, the mixing ratio of the former and the latter is preferably 9: 1 to 1: 9, more preferably 8: 2 to 2: 8, and most preferably 7: 3 to 5: 5. It is.
The amount of the component (S) used is not particularly limited, but is a concentration that can be applied to the support and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is 2 -20% by mass, preferably 3-15% by mass.

[Resist Composition of Sixth Aspect]
<(A ') component>
The component (A ′) is not particularly limited, and those conventionally used as base material components for chemically amplified resists can be used. Specifically, the same resins as those mentioned as the component (A1) of the resist composition of the fifth aspect (however, the terminal group (i-1) is not present at the end of the main chain) can be mentioned.

<(B ′) component>
Examples of the component (B ′) include the same components as the component (B) of the resist composition of the fifth aspect.
As the component (B ′), one type may be used alone, or two or more types may be used in combination.
In the present invention, as the component (B ′), an onium salt having a fluorinated alkyl sulfonate ion as an anion is preferably used.
The content of the component (B ′) in the resist composition is preferably 0.5 to 30 parts by mass, more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the component (A ′). By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<(C ′) component>
Component (C ′) is an additive component made of the polymer of the present invention.
When the component (C ′) is brought into contact with an alkali developer, the —O—R ² in the terminal group (i-1) is dissociated by hydrolysis, and at the same time, a hydrophilic group is formed to make the hydrophilic property. improves.
The component (C ′) only needs to have the terminal group (i-1) at at least one end of the main chain, and the configuration other than the terminal portion is not particularly limited, and depends on the use. What is necessary is just to set suitably. For example, when the resist composition of the present invention is for immersion exposure, the component (C ′) preferably contains a fluorine atom.

In the present invention, the polymer used as the component (C ′) preferably has a structural unit having a base dissociable group that is dissociated by the action of an alkali developer (hereinafter referred to as structural unit (c1)).
The base dissociable group in the structural unit (c1) is an alkali developer (for example, 2.38% by mass of tetramethylammonium hydroxide (TMAH) aqueous solution, similarly to —O—R ² in the terminal group (i-1)). (23 ° C.)).
The base dissociable group is not particularly limited as long as it falls within the above definition, and may contain a fluorine atom or may not contain a fluorine atom. It is preferable to contain. In particular, it is preferable that the fluorine atom contained in the structural unit (c1) exists only in the base dissociable group. When the base dissociable group contains a fluorine atom, when the base dissociable group is dissociated by the action of the alkali developer, the fluorine atom is also dissociated from the structural unit (c1), so that the affinity for the alkali developer is further increased. .

  As a preferred structural unit (c1), a structural unit having a group represented by the following general formula (i-11) can be mentioned.

［式中、Ｒ^２は前記と同じである。］

[Wherein R ² is the same as defined above. ]

  Moreover, as a structural unit (c1) other than the above, a structural unit having a group represented by any one of the following general formulas (i-12) to (i-14) can be given.

［式中、Ｒ^２’はそれぞれフッ素原子を含む有機基である。］

[Wherein R ² ′ is an organic group containing a fluorine atom. ]

In formulas (i-11) to (i-14), R ² and R ² ′ are each preferably a hydrocarbon group having a fluorine atom. Specific examples of the hydrocarbon group having a fluorine atom include the same groups as those described above for R ² in formula (i-1).
R ² and R ² ′ are each preferably a fluorinated alkyl group, more preferably a fluorinated alkyl group having 1 to 5 carbon atoms, —CH ₂ —CF ₃ , —CH ₂ —CF ₂ —CF ₃ , — CH (CF ₃ ) ₂ , —CH ₂ —CF ₂ —CF ₂ —CF ₃ , and —CH ₂ —CH ₂ —CF ₂ —CF ₂ —CF ₂ —CF ₃ are particularly preferred.
The structural unit (c1) preferably has at least one selected from the group consisting of groups represented by formulas (i-11) to (i-14), is excellent in the effects of the present invention, and is synthesized. From the viewpoint of ease, it is more preferable to have a group represented by formula (i-11) or (i-12), and it is most preferable to have a group represented by formula (i-11).

  As a suitable thing of a structural unit (c1), the structural unit represented by the following general formula (c1-1) or (c1-2) is mentioned, for example.

［式中、Ｒはそれぞれ独立して水素原子、低級アルキル基またはハロゲン化低級アルキル基であり；Ｘは二価の有機基であり、Ａ_ａｒｙｌは置換基を有していてもよい二価の芳香族環式基であり、Ｘ_０１は単結合または二価の連結基であり、Ｒ^２はそれぞれ前記と同じである。］

[Wherein, each R is independently a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X is a divalent organic group, and A _aryl is an optionally substituted divalent group. It is an aromatic cyclic group, X ₀₁ is a single bond or a divalent linking group, and R ² is the same as defined above. ]

In formula (c1-1) or (c1-2), R ² is the same as described above.
The lower alkyl group in R is preferably linear or branched, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, An isopentyl group, a neopentyl group, etc. are mentioned.
Specific examples of the halogenated lower alkyl group include groups in which some or all of the hydrogen atoms of the “lower alkyl group” 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.
In the present invention, R is preferably a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group, and more preferably a hydrogen atom or a methyl group in terms of industrial availability.

In general formula (c1-1), X is a divalent organic group.
X may or may not have an acid dissociable portion. The “acid-dissociable part” means a part in the organic group that is dissociated by the action of an acid generated by exposure. When X has an acid dissociable part, it is preferable to have an acid dissociable part having a tertiary carbon atom.
Preferred examples of X include a hydrocarbon group which may have a substituent, a group containing a hetero atom, and the like.
The term “having a substituent” for the hydrocarbon group means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.
More specifically, examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.
The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 1 to 5, and most preferably 1 to 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [ — (CH ₂ ) ₃ —], tetramethylene group [— (CH ₂ ) ₄ —], pentamethylene group [— (CH ₂ ) ₅ —] and the like can be mentioned.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and 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 -, - 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 - , etc. Alkyltrimethylene group of —CH (CH ₃ ) CH ₂ CH ₂ CH ₂ —, —CH _{2 CH (CH 3) CH 2} CH 2 - alkyl alkylene group such as an alkyl tetramethylene group such like. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group containing a ring include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group described above as a chain-like aliphatic group. And a group bonded to the terminal of the aromatic hydrocarbon group or interposed in the middle of the chain-like aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane. As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

The “heteroatom” in the divalent group containing a heteroatom 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.
As the divalent group containing a hetero atom, specifically, —O—, —C (═O) —, —C (═O) —O—, carbonate bond (—O—C (═O) —O -), -NH-, ^-NR04 ( ^R04 is an alkyl group)-, -NH-C (= O)-, = N-, or a combination of these groups and a divalent hydrocarbon group, etc. Is mentioned. Examples of the divalent hydrocarbon group include the same hydrocarbon groups that may have a substituent as described above, and a linear or branched aliphatic hydrocarbon group is preferable.

In general formula (c1-2), A _aryl is a divalent aromatic cyclic group which may have a substituent. Specific examples of A _aryl include a group obtained by removing two hydrogen atoms from an aromatic hydrocarbon ring which may have a substituent.
The ring skeleton of the aromatic cyclic group for A _aryl, preferably has a carbon number of 6 to 15, for example, a benzene ring, a naphthalene ring, a phenanthrene ring, anthracene ring and the like. Among these, a benzene ring or a naphthalene ring is particularly preferable.
In A _aryl , examples of the substituent that the aromatic cyclic group may have include a halogen atom, an alkyl group, an alkoxy group, a halogenated lower alkyl group, and an oxygen atom (═O). Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom. The substituent that the aromatic cyclic group of A _aryl may have is preferably a fluorine atom.
The aromatic cyclic group of A _aryl may have no substituent, may have a substituent, and preferably has no substituent.
In A _aryl , when the aromatic cyclic group has a substituent, the number of substituents may be one, two or more, and one or two. Is preferable, and one is more preferable.
X ₀₁ is a single bond or a divalent linking group. Examples of the divalent linking group include an alkylene group having 1 to 10 carbon atoms, —O—, —C (═O) —, —C (═O) —O—, and a carbonate bond (—O—C (═O). -O-), -NH-C (= O)-, or a combination thereof may be mentioned, and a combination of -O- and an alkylene group having 1 to 10 carbon atoms is most preferable.
Examples of the alkylene group having 1 to 10 carbon atoms include linear, branched or cyclic alkylene groups, linear or branched alkylene groups having 1 to 5 carbon atoms, and 4 to 10 carbon atoms. A cyclic alkylene group is preferred.

Among the structural units represented by the general formula (c1-1), structural units represented by the following general formulas (c1-11) to (c1-14) are exemplified.
Moreover, as a suitable unit among the structural units represented by the general formula (c1-2), structural units represented by the following general formulas (c1-21) to (c1-24) can be given.

In general formulas (c1-11) to (c1-14), (c1-21) to (c1-24), (c1-25) to (c1-27), R and R ² are the same as defined above. Yes; R ^{51 to} R ⁵² are each independently an alkyl group having 1 to 10 carbon atoms; R ^{53 to} R ⁵⁴ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; a1, a2 , A3, a5, a7, a9, and a11-a13 are each independently an integer of 1-5; a4, a6, a8, and a10 are each independently an integer of 0-5; a14-a16 Is an integer of 0 to 5; b1 to b5 are each independently 0 or 1; R ⁵ is a substituent, and e is an integer of 0 to 2.
In formulas (c1-11) to (c1-14), (c1-21) to (c1-24), and (c1-25) to (c1-27), R is preferably a hydrogen atom or a methyl group.
In formula (c1-11), a1 is preferably an integer of 1 to 3, and more preferably 1 or 2.
In formula (c1-12), a2 and a3 are each independently preferably an integer of 1 to 3, and more preferably 1 or 2.
In formula (c1-13), a4 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and most preferably 0 or 1.
a5 is preferably an integer of 1 to 3, and more preferably 1 or 2.
Examples of the substituent for R ⁵ include a halogen atom, a lower alkyl group, an alkoxy group having 1 to 5 carbon atoms, a halogenated lower alkyl group, and an oxygen atom (═O). Examples of the lower alkyl group include the same lower alkyl groups as those described above for R. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom. Examples of the halogenated lower alkyl group include the same halogenated lower alkyl groups as those described above for R.
e is preferably 0 or 1, and particularly preferably 0 from an industrial viewpoint.
b2 is preferably 0.
In formula (c1-14), a6 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and most preferably 0 or 1.
a7 is preferably an integer of 1 to 3, and more preferably 1 or 2.
b3 is preferably 0.
R ⁵ and e are the same as defined above.

In formula (c1-21), a8 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and most preferably 0 or 1.
a9 is preferably an integer of 1 to 3, and more preferably 1 or 2.
b4 is preferably 0.
R ⁵ and e are the same as defined above.
In formula (c1-22), a10 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and most preferably 0 or 1.
a11 is preferably an integer of 1 to 3, and more preferably 1 or 2.
b5 is preferably 0.
R ⁵ and e are the same as defined above.
In formula (c1-23), a12 is preferably an integer of 1 to 3, and more preferably 1 or 2.
R ⁵ and e are the same as defined above.
In formula (c1-24), a13 is preferably an integer of 1 to 3, and more preferably 1 or 2.
R ⁵ and e are the same as defined above.
In formulas (c1-25) to (c1-27), each of a14, a15, and a16 is preferably 0 to 3, more preferably 0 to 2, and most preferably 0 or 1.
R ^{51 to} R ⁵² are preferably each independently a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Examples include isobutyl group, tert-butyl group, tert-amyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, norbornyl group, isobornyl group, tricyclodecanyl group, adamantyl group, and tetracyclododecanyl group. C1-C6 is more preferable, C1-C4 is especially preferable, and a methyl group or an ethyl group is the most preferable.
R ^{53 to} R ⁵⁴ are preferably each independently a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. The linear, branched or cyclic alkyl group having 1 to 10 carbon atoms in R ^{53 to} R ⁵⁴ is the same as R ^{51 to} R ⁵² described above.
In formulas (c1-26) to (c1-27), R ⁵ and e are the same as defined above.

  Specific examples of the structural units represented by the general formulas (c1-11) to (c1-14) and general formulas (c1-21) to (c1-27) are shown below.

  The structural unit (c1) is selected from the group consisting of structural units represented by any one of the general formulas (c1-11) to (c1-14) and (c1-21) to (c1-24). At least one is preferable, and at least one selected from the group consisting of structural units represented by any of the general formulas (c1-11) to (c1-13), (c1-21) and (c1-22) The seed is more preferable, and at least one selected from the group consisting of the structural units represented by the general formula (c1-11) or (c1-22) is particularly preferable.

In the component (C ′), as the structural unit (c1), one type may be used alone, or two or more types may be used in combination.
In the component (C ′), the proportion of the structural unit (c1) is preferably 10 mol% or more, preferably 10 to 90 mol%, preferably 20 to 80 with respect to the total of all the structural units constituting the component (C ′). More preferably, mol% is more preferable, 30-80 mol% is further more preferable, and 40-80 mol% is especially preferable. Moreover, a homopolymer may be sufficient. When the proportion of the structural unit (c1) is 10 mol% or more, in forming a resist pattern, it is hydrophobic during immersion exposure and is hydrophilic during alkali development, reducing defects in the reattachment system, and during immersion exposure. This improves the scan followability.
Although the upper limit of this ratio is not specifically limited, 90 mol% or less is preferable and 80 mol% or less is more preferable. If it is 90 mol% or less, defects derived from immersion scanning exposure can be suppressed.

In the present invention, the polymer used as the component (C ′) includes, in addition to the structural unit (c1), a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group (hereinafter referred to as structural unit (c2)). It is preferable to have.
As the structural unit (c2), for example, the same structural units as those described for the component (A) can be used.

  In the present invention, the structural unit (c2) is particularly preferably a structural unit represented by the following general formula (c2-1).

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり；Ｗは下記一般式（ｗ−１）〜（ｗ−４）のいずれかにより表される基である。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; W represents a group represented by any one of the following general formulas (w-1) to (w-4). ]

［式（ｗ−１）中、Ｒ^２１は炭素数２以上のアルキル基であり、Ｒ^２２およびＲ^２３は相互に結合して炭素数７以上の単環式の脂肪族環式基を形成している。式（ｗ−２）中、Ｒ^２４は炭素数３以上の分岐鎖状のアルキル基であり、Ｒ^２５およびＲ^２６は相互に結合して脂肪族環式基を形成している。式（ｗ−３）中、Ｒ^２７は酸解離性溶解抑制基であり、Ｒ^２８は２価の連結基である。式（ｗ−４）中、Ｒ^２９は直鎖状もしくは分岐鎖状のアルキル基または脂肪族環式基であり、ｎは０〜３の整数であり、Ｒ^３０およびＲ^３０’はそれぞれ独立して直鎖状もしくは分岐鎖状のアルキル基または水素原子であり、Ｒ^２９およびＲ^３０が相互に結合して脂肪族環式基を形成していてもよい。］

[In Formula (w-1), R ²¹ is an alkyl group having 2 or more carbon atoms, and R ²² and R ²³ are bonded to each other to form a monocyclic aliphatic cyclic group having 7 or more carbon atoms. ing. In the formula (w-2), R ²⁴ is a branched alkyl group having 3 or more carbon atoms, and R ²⁵ and R ²⁶ are bonded to each other to form an aliphatic cyclic group. In the formula (w-3), R ²⁷ is an acid dissociable, dissolution inhibiting group, and R ²⁸ is a divalent linking group. In the formula (w-4), R ²⁹ is a linear or branched alkyl group or an aliphatic cyclic group, n is an integer of 0 to 3, and R ³⁰ and R ³⁰ ′ are each independently A linear or branched alkyl group or a hydrogen atom, and R ²⁹ and R ³⁰ may be bonded to each other to form an aliphatic cyclic group. ]

R in the formula (c2-1) is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group. Examples of R include those similar to R in formula (c1-1) or (c1-2).
W is a group represented by any one of the general formulas (w-1) to (w-4).
In formula (w-1), R ²¹ is an alkyl group having 2 or more carbon atoms, and R ²² and R ²³ are bonded to each other to form a monocyclic aliphatic cyclic group having 7 or more carbon atoms. Yes.
The alkyl group for R ²¹ may be linear, branched or cyclic.
When the alkyl group is linear or branched, it preferably has 2 to 5 carbon atoms, and is ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl. Group, isopentyl group, neopentyl group and the like. Among these, an ethyl group or a propyl group is more preferable, and an ethyl group is most preferable.
When the alkyl group is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specific examples include a group obtained by removing one hydrogen atom from a monocycloalkane; a group obtained by removing one hydrogen atom from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane; Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one hydrogen atom from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
R ²¹ is preferably a linear or branched alkyl group.

In formula (w-1), R ²² and R ²³ are bonded to each other to form a monocyclic aliphatic cyclic group having 7 or more carbon atoms together with the carbon atom to which R ²² and R ²³ are bonded. ing.
The monocyclic aliphatic cyclic group preferably has 8 or more carbon atoms. The monocyclic aliphatic cyclic group preferably has 12 or less carbon atoms, more preferably 10 or less, and even more preferably 9 or less.
The aliphatic cyclic group may be saturated or unsaturated, but is preferably saturated. Further, it may be a hydrocarbon group consisting of only carbon atoms and hydrogen atoms, and may have other atoms (hetero atoms such as oxygen atom, nitrogen atom, sulfur atom), but is a hydrocarbon group. It is preferable.
A substituent may be bonded to the aliphatic cyclic group. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

  Preferable specific examples of the group represented by the formula (w-1) include the following.

In the formula (w-2), R ²⁴ is a branched alkyl group having 3 or more carbon atoms, and R ²⁵ and R ²⁶ are bonded to each other to form an aliphatic cyclic group.
The alkyl group for R ²⁴ preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group and the like, and isopropyl group is most preferable.

In formula (w-2), R ²⁵ and R ²⁶ are bonded to each other to form an aliphatic cyclic group together with the carbon atom to which R ²⁵ and R ²⁶ are bonded.
The aliphatic cyclic group may be monocyclic or polycyclic.
The aliphatic cyclic group may be saturated or unsaturated, but is preferably saturated. Further, it may be a hydrocarbon group consisting of only carbon atoms and hydrogen atoms, and may have other atoms (hetero atoms such as oxygen atom, nitrogen atom, sulfur atom), but is a hydrocarbon group. It is preferable.
The aliphatic cyclic group preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms.
Specifically, the aliphatic cyclic group is a group in which one hydrogen atom is removed from a monocycloalkane; one hydrogen atom is removed from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. And the like. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one hydrogen atom from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
A substituent may be bonded to the aliphatic cyclic group. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

  Preferable specific examples of the group represented by the formula (w-2) include the following.

［式中、Ｒ^２４は前記と同じであり、ｇは０〜３の整数である。］

[Wherein, R ²⁴ is the same as defined above, and g is an integer of 0 to 3. ]

  g is preferably an integer of 1 to 3, and more preferably 1 or 2.

In the formula (w-3), R ²⁷ is an acid dissociable, dissolution inhibiting group, and R ²⁸ is a divalent linking group.
The acid dissociable, dissolution inhibiting group for R ^{27 is} an acid dissociation that is dissociated by the action of an acid generated from the component (B) upon exposure when the component (C ′) is blended with the resist composition together with the component (B). In addition to the above, before the dissociation, it has an alkali dissolution inhibiting property that suppresses the solubility of the component (C ′) in an alkali developer.
The acid dissociable, dissolution inhibiting group for R ²⁷ is not particularly limited, and those that have been proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists can be used. Specifically, in the component (A) described above, the same as those exemplified as the acid dissociable, dissolution inhibiting group included in the structural unit (a1) can be used.

Examples of the divalent linking group for R ²⁸ include the same groups as those described above for X in the formula (c1-1).
In the present invention, the divalent linking group for R ²⁸ is preferably an alkylene group, a divalent aliphatic cyclic group or a divalent linking group containing a hetero atom.
When R ²⁸ is an alkylene group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Most preferably it is.
In the case where R ²⁸ is a divalent aliphatic cyclic group, the “aliphatic group” in the formula (w-2) is used except that a group in which two or more hydrogen atoms are removed is used as the aliphatic cyclic group. The same as described in “Aromatic cyclic group” can be used. The aliphatic cyclic group is particularly preferably a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane or tetracyclododecane.

When R ²⁸ is a divalent linking group containing a hetero atom, examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —O—, —C (═O) —, -O-C (= O) -O-, -C (= O) -NH-, -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—, a group represented by the formula —A—O—B—, a formula — [A—C (═O) —O] _m —. Examples thereof include a group represented by B-. Here, A and B are each independently a divalent hydrocarbon group which may have a substituent, and m is an integer of 0 to 3.
When R ²⁸ is —NH—, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. It is particularly preferred that
When R ²⁸ is —A—O—B— or — [A—C (═O) —O] _m —B—, A and B may each independently have a substituent. It is a divalent hydrocarbon group.
m is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 1.

The hydrocarbon group in A may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group for A may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group for A include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in the structure.
The “linear or branched aliphatic hydrocarbon group” in A preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 5, and particularly preferably 1 or 2. preferable.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group, an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [— (CH ₂ ) ₃ -], tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and 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 -, - 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 - , etc. Alkyltrimethylene group of —CH (CH ₃ ) CH ₂ CH ₂ CH ₂ —, —CH _{2 CH (CH 3) CH 2} CH 2 - alkyl alkylene group such as an alkyl tetramethylene group such like. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

As the “aliphatic hydrocarbon group including a ring in the structure” in A, a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), the cyclic aliphatic hydrocarbon group Includes a group bonded to the terminal of the chain aliphatic hydrocarbon group described above or interposed in the middle of the chain aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

  As A, 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. The ethylene group is most preferred.

Examples of the hydrocarbon group for B include the same divalent hydrocarbon groups as those described above for A.
B is preferably a linear or branched aliphatic hydrocarbon group, particularly preferably a methylene group, an ethylene group or an alkylmethylene group.
The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

In the group represented by the formula — [A—C (═O) —O] _m —B—, m is an integer of 0 to 3, preferably an integer of 0 to 2, and 0 or 1 Is more preferable and 1 is most preferable.

In the present invention, the divalent linking group for R ²⁸ is preferably a divalent group containing a hetero atom, and particularly preferably a linear group having an oxygen atom as a hetero atom, for example, a group containing an ester bond.
Among them, a group represented by the above-described —A—O—B— or —A—C (═O) —O—B— is preferable, and in particular, — (CH ₂ ) _a —C (═O) —O— ( CH _{2) b} - group is particularly desirable.
a is an integer of 1 to 5, preferably 1 or 2, and most preferably 2.
b is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.

In formula (w-4), R ²⁹ represents a linear or branched alkyl group or an aliphatic cyclic group.
When R ²⁹ is linear or branched, it preferably has 1 to 15 carbon atoms, more preferably 1 to 5, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ²⁹ is an aliphatic cyclic group, the aliphatic cyclic group is appropriately selected from monocyclic or polycyclic aliphatic cyclic groups that have been proposed in a number of conventional ArF resists and the like. Examples thereof include those similar to the above “aliphatic cyclic group”.
The aliphatic cyclic group for R ²⁹ preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.

In formula (w-4), n is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
R ³⁰ and R ³⁰ ′ are each independently a linear or branched alkyl group or a hydrogen atom.
The linear or branched alkyl group for R ³⁰ and R ³⁰ ′ is preferably a lower alkyl group. Examples of the lower alkyl group include the same lower alkyl groups as those described above for R, and are preferably a methyl group or an ethyl group, and most preferably a methyl group.
In the present invention, it is preferable that at least one of R ³⁰ and R ³⁰ ′ is a hydrogen atom.

In the above formula (w-4), R ²⁹ and R ³⁰ may be bonded to each other to form an aliphatic cyclic group.
In this case, an aliphatic cyclic group is formed by R ²⁹ , R ³⁰ , —O— (CH ₂ ) _n —, and the carbon atom to which R ³⁰ is bonded. As this aliphatic cyclic group, a 4-7 membered ring is preferable and a 4-6 membered ring is more preferable. Specific examples of the aliphatic cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  Preferable specific examples of the group represented by the formula (w-4) include groups represented by the following formulas (w-4-1) to (w-4-12).

［式中、Ｒ^１３は水素原子またはメチル基であり、ｇは前記と同じである。］

[Wherein, R ¹³ represents a hydrogen atom or a methyl group, and g is the same as defined above. ]

In the component (C ′), as the structural unit (c2), one type of structural unit may be used alone, or two or more types may be used in combination.
In the component (C ′), the proportion of the structural unit (c2) is preferably 5 to 80 mol%, more preferably 10 to 60 mol%, based on the total of all structural units constituting the component (C ′). -50 mol% is more preferable, and 20-40 mol% is especially preferable. When the proportion of the structural unit (c2) is not less than the lower limit of the above range, in the formation of the resist pattern, the characteristics that it is hydrophobic during immersion exposure and the hydrophilicity increases when exposure and PEB are performed are more remarkable. become. In addition, the bridge defect can be suppressed in the line and space pattern, and the defective opening defect can be suppressed in the contact hole pattern. Further, the proportion of hydrocarbon groups is improved, and the scan followability is improved. When the amount is not more than the upper limit, the balance with the structural unit (c1) is good, and the effect of containing the structural unit (c1) is sufficiently obtained.

In the present invention, the polymer used as the component (C ′) may have another structural unit other than the structural units (c1) to (c2) (hereinafter referred to as the structural unit (c3)). Good.
The structural unit (c3) is not particularly limited as long as it is a structural unit derived from a compound copolymerizable with the monomer that derives the structural unit (c1). Examples of such a structural unit include those conventionally proposed as a structural unit of a base resin for a chemically amplified resist (for example, structural units (a2) to (a4) mentioned in the component (A)).

In the present invention, the component (C ′) is preferably a polymer having the structural unit (c1), and more preferably a copolymer having the structural unit (c1) and the structural unit (c2).
Examples of the copolymer include a copolymer composed only of the structural unit (c1) and the structural unit (c2); a copolymer composed of the structural unit (c1), the structural unit (c2), and the structural unit (c3). It is done.
In the present invention, the component (C ′) is preferably a copolymer composed of the structural unit (c1) and the structural unit (c2).

The mass average molecular weight (Mw) of the component (C ′) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and more preferably 4000 to 25000. Is most preferred. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.
The component (C ′) can be obtained, for example, by polymerizing a monomer that induces each structural unit constituting the component (C ′) by radical polymerization using the radical polymerization initiator of the present invention. .
As the monomer for deriving each structural unit, it may be synthesized or commercially available.

For example, as a monomer for deriving the structural unit (c1), a compound in which a base dissociable group and a polymerizable group are bonded via a divalent linking group can be mentioned.
The “polymerizable group” is a group that allows the compound having the polymerizable group to be polymerized by radical polymerization or the like, and examples thereof include a group having an ethylenic double bond. Examples of the group having an ethylenically unsaturated double bond, for example, group (wherein, R is as defined above.) Represented by CH 2 = _CR- and the like.
Examples of the divalent linking _{group, -A} aryl _{-X 01} - _(wherein, A _{aryl, X 01} are the same as defined above.), - C (= O ) -O-X- ( wherein, X Is the same as defined above).
For example, the monomer for deriving the structural unit represented by the general formula (c1-1) and the monomer for deriving the structural unit represented by the formula (c1-2) are respectively represented by the following general formula (c0). -1) The fluorine-containing compound represented, The compound represented by the following general formula (c0-2) is mentioned.

［式中、Ｒ、Ｘ、Ａ_ａｒｙｌ、Ｘ_０１およびＲ^２はそれぞれ前記と同じである。］

[Wherein, R, X, A _aryl , X ₀₁ and R ² are the same as defined above. ]

The compound represented by formula (c0-1) or (c0-2) (hereinafter referred to as compound (C0)) is, for example, represented by the following general formula (c0-1-0) or (c0-2-0). R ² [R ² is as defined above] for the carboxy group of the compound represented (hereinafter collectively referred to as compound (V-1)). ] (Replace the hydrogen atom at the terminal of the carboxy group with R ² ).
R ² can be introduced using a conventionally known method. For example, the compound (C0) can be produced by reacting the compound (V-1) with the compound (V-2) represented by the following general formula (V-2).

［式中、Ｒ、Ｘ、Ａ_ａｒｙｌ、Ｘ_０１、およびＲ^２はそれぞれ前記と同じである。］

[Wherein, R, X, A _aryl , X ₀₁ , and R ² are the same as defined above. ]

The method for reacting compound (V-1) and compound (V-2) is not particularly limited. For example, compound (V-1) and compound (V-2) are reacted in the presence of a base in a reaction solvent. ).
As a compound (V-1) and a compound (V-2), a commercially available thing may be used and what was synthesize | combined may be used.
As the compound (V-1), for example, a low molecular weight compound derived from an acrylate ester such as carboxyalkyl (meth) acrylate and succinic acid mono ((meth) acryloyloxyalkyl); a structure derived from an acrylate ester A polymer compound having a unit can be used.
As the compound (V-2), for example, fluorinated alkyl alcohol or the like can be used.
Any reaction solvent may be used as long as it can dissolve the starting compounds (I) and (II). Specifically, tetrahydrofuran (THF), acetone, dimethylformamide (DMF), dimethylacetamide, dimethylsulfoxide ( DMSO), acetonitrile and the like.
Examples of the base include organic bases such as triethylamine, 4-dimethylaminopyridine (DMAP) and pyridine; inorganic bases such as sodium hydride, K ₂ CO ₃ and Cs ₂ CO ₃ .
Examples of the condensing agent include carbodiimide reagents such as ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride, dicyclohexylcarboimide (DCC), diisopropylcarbodiimide, carbodiimidazole, tetraethylpyrophosphate, benzotriazole-N-hydroxytrisdimethylaminophosphonium hexa Fluorophosphide salt (Bop reagent) and the like.
Moreover, you may use an acid as needed. As the acid, those usually used in dehydration condensation and the like can be used. Specifically, inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p- Organic acids such as toluenesulfonic acid can be mentioned. These may be used alone or in combination of two or more.
About 1-3 equivalent is preferable with respect to compound (V-1), and, as for the addition amount of a compound (V-2), 1-2 equivalent is more preferable.
The reaction temperature is preferably -20 to 40 ° C, more preferably 0 to 30 ° C.
Although reaction time changes also with the reactivity, reaction temperature, etc. of a compound (V-1) and a compound (V-2), 30-480 minutes are preferable normally and 60-360 minutes are more preferable.

  The content of the component (C ′) in the resist composition of the sixth aspect of the present invention is preferably 0.1 to 50 parts by mass, and 0.1 to 40 parts by mass with respect to 100 parts by mass of the component (A ′). Is more preferable, 0.5-30 mass parts is especially preferable, and 1-15 mass parts is the most preferable. By setting it to be equal to or more than the lower limit of the above range, the hydrophobicity of the resist film formed using the resist composition is improved, and the hydrophobicity suitable for immersion exposure is obtained. When it is at most the upper limit value, the lithography properties are improved.

<Optional component>
The resist composition according to the sixth aspect of the present invention includes, as an optional component, a nitrogen-containing organic compound (D ′) (hereinafter referred to as (D) for the purpose of improving the resist pattern shape, stability with time, etc. ') Referred to as component).
Examples of the component (D ′) include the same components as the component (D) of the resist composition of the fifth aspect.
(D ') component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A') component.

The resist composition according to the sixth aspect of the present invention includes an organic carboxylic acid, a phosphorus oxoacid, and an oxyacid as an optional component for the purpose of preventing sensitivity deterioration, improving the resist pattern shape, stability over time, and the like. You may contain the at least 1 sort (s) of compound (E ') (henceforth (E') component) selected from the group which consists of a derivative | guide_body.
Examples of the component (E ′) include those similar to the component (E) of the resist composition of the fifth aspect.
The component (E ′) is usually used at a ratio of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A ′).

  The resist composition according to the sixth aspect of the present invention further contains miscible additives as desired, for example, an additional resin for improving the performance of the resist film, a surfactant for improving the coating property, and dissolution. An inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

The resist composition according to the sixth aspect of the present invention can be produced by dissolving the material in an organic solvent (hereinafter, also referred to as (S ′) component).
As the component (S ′), any component can 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 can be used. Or it can select and use 2 or more types suitably. Specifically, the same thing as (S) component of the resist composition of the said 5th aspect is mentioned.
The amount of the component (S ′) used is not particularly limited, but is a concentration that can be applied to the support and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is It is used in a range of 2 to 20% by mass, preferably 3 to 15% by mass.

The resist compositions according to the fourth to sixth aspects of the present invention have good lithography characteristics and characteristics suitable for immersion exposure (hydrophobic and hydrophobic properties), which are characteristics required for resist compositions used for immersion exposure. Therefore, it is suitable as a resist composition for immersion exposure.
Since the resist film formed using the resist composition of the present invention contains the polymer of the present invention, the resist film has high hydrophobicity at the time of immersion exposure, and various treatments after the immersion exposure (PEB treatment, alkali development, etc.) ) Has the property of decreasing hydrophobicity (increasing hydrophilicity).
That is, first, the polymer of the present invention has an end group (i-1) having a structure in which a group (—O—R ² ) dissociated by the action of an alkali developer is bonded to a carbonyl group at the end of the polymer main chain. Have. Therefore, when an alkali developer is brought into contact with the polymer, hydrolysis occurs due to the action of the alkali developer, and —O—R ² is dissociated to form a carboxy group. As a result, the hydrophilic property of the polymer of the present invention is ascertained. Improves. In particular, the presence of the terminal group (i-1) at the end of the polymer main chain can enhance the effect introduced, as compared with the case where the polymer is introduced into the polymer side chain. This is because the polymer is a mass (aggregate), so if there is a base dissociable group in the side chain, the developer is difficult to penetrate into the interior during alkali development, while the base dissociable group is difficult to dissociate. If there is a base-dissociable group at the terminal, it is presumed that the base-dissociable group jumps out of the polymer lump and thus easily comes into contact with the developer and is easily dissociated.
Therefore, the resist film formed using the resist composition of the present invention containing the polymer of the present invention has a high hydrophobicity at the time of exposure as compared with the case where the polymer of the present invention is not included, It has the property that the hydrophobicity is reduced (hydrophilicity is improved) during alkali development. This property is particularly remarkable when R ² is a highly hydrophobic group such as a hydrocarbon group having an electron withdrawing group, particularly a hydrocarbon group having a fluorine atom.
The resist film with improved hydrophobicity at the time of exposure is very excellent in water followability required when immersion exposure is performed using a scanning immersion exposure machine as described in Non-Patent Document 1. ing.
Further, in the prior art, if the resist film is highly hydrophobic, the surface of the resist pattern after development is defective (for example, a watermark defect due to the influence of an immersion medium such as water or an alkaline developer, and other bridge defects or defective openings). However, since the hydrophilicity of the resist film formed using the resist composition of the present invention increases after immersion exposure, the occurrence of the defect can be reduced. The above problem is particularly significant in the case of a positive resist composition in which a resist film in an unexposed portion remains without being removed, and the present invention is particularly effective in the case of a positive type.

The hydrophobicity of the resist film includes the contact angle with water, for example, the static contact angle (the angle formed by the surface of the water droplet on the resist film in the horizontal state and the resist film surface), and the dynamic contact angle (the tilted resist film). The contact angle when the water droplet starts to fall (fall angle), the contact angle at the front end point in the water drop direction (advance angle), the contact angle at the rear end point in the fall direction (retreat angle).) It can evaluate by measuring etc. For example, the higher the hydrophobicity of the resist film, the larger the static contact angle, the advancing angle, and the receding angle, while the smaller the falling angle.
Here, as shown in FIG. 1, when the plane 2 on which the droplet 1 is placed is gradually tilted, the advancing angle starts to move (drop) on the plane 2 when the plane 1 is gradually inclined. The angle θ1 formed by the surface of the droplet at the lower end 1a of the droplet 1 and the plane 2 at that time. At this time (when the droplet 1 starts to move (drop) on the plane 2), the angle θ2 formed by the droplet surface at the upper end 1b of the droplet 1 and the plane 2 is a receding angle, The inclination angle θ3 of the plane 2 is the falling angle.
In this specification, the advancing angle, the receding angle, and the falling angle are measured as follows.
First, a resist composition solution is spin-coated on a silicon substrate, and then heated at 110 ° C. for 60 seconds to form a resist film. Next, with respect to the resist film, DROP MASTER-700 (product name, manufactured by Kyowa Interface Science Co., Ltd.), AUTO SLIDING ANGLE: SA-30DM (product name, manufactured by Kyowa Interface Science Co., Ltd.), AUTO DISPENSER: AD-31 ( It can be measured using a commercially available measuring device such as a product name (manufactured by Kyowa Interface Science Co., Ltd.).

When the resist composition of the present invention is for immersion exposure, the resist film obtained using the resist composition should have a measured value of the static contact angle before exposure and development of 70 degrees or more. Preferably, it is 65-100 degree | times, More preferably, it is 75-100 degree | times. When the static contact angle is at least the lower limit degree, the substance elution suppressing effect during immersion exposure is improved. The reason for this is not clear, but one of the main factors may be related to the hydrophobicity of the resist film. That is, since the immersion medium is water-based, such as water, it has high hydrophobicity. Therefore, after immersion exposure is performed, the immersion medium is quickly removed from the resist film surface after the immersion medium is removed. It is presumed that the fact that it can be removed has an effect. Further, when the receding angle is not more than the upper limit value, the lithography characteristics and the like are good.
For the same reason, the resist film obtained by using the resist composition of the present invention preferably has a measured value of the receding angle before exposure and development of 50 degrees or more, and preferably 50 to 150 degrees. More preferably, it is 50 to 130 degrees, particularly preferably 53 to 100 degrees.
Moreover, the resist film obtained using the resist composition of the present invention preferably has a measured value of the falling angle before exposure and development of 30 degrees or less, more preferably 5 to 30 degrees, It is particularly preferably 5 to 25 degrees, and most preferably 5 to 23 degrees. When the sliding angle is less than or equal to the upper limit value, the substance elution suppression effect during immersion exposure is improved. Further, when the sliding angle is at least the lower limit value, the lithography properties and the like are good.
The above-mentioned various angles (dynamic contact angle (advance angle, receding angle, falling angle, etc.), static contact angle) are determined according to the composition of the resist composition (for example, the composition of the polymer of the present invention (type of structural unit). And ratio) and blending amount) can be adjusted. For example, a polymer containing a fluorine atom (for example, a polymer in which R ^{2 at the} end of the main chain contains a fluorine atom, a structural unit containing a fluorine atom as the base dissociable group (f1) increases the amount of the polymer of the present invention. And the like), the hydrophobicity of the resulting resist composition is increased, the advancing angle, the receding angle, and the static contact angle are increased, and the sliding angle is decreased.

Further, by using the resist composition of the present invention, substance elution from the resist film during immersion exposure can be suppressed.
In other words, liquid immersion exposure will be described in detail later, but at the time of exposure, the portion between the lens and the resist film on the wafer, which is conventionally filled with an inert gas such as air or nitrogen, is determined from the refractive index of air. And a step of performing exposure (immersion exposure) in a state filled with a solvent (immersion medium) having a large refractive index. In immersion exposure, when the resist film and the immersion solvent come into contact with each other, elution (substance elution) of substances ((B) component, (D) component, etc.) in the resist film into the immersion solvent occurs. Substance elution causes phenomena such as alteration of the resist layer and change in the refractive index of the immersion solvent, thereby deteriorating lithography characteristics. The amount of this substance elution is affected by the characteristics of the resist film surface (for example, hydrophilicity / hydrophobicity). For example, it is presumed that the elution of the substance is reduced by increasing the hydrophobicity of the resist film surface.
Since the resist film formed using the resist composition of the present invention has the polymer of the present invention, the hydrophobicity before exposure and development is higher than when the polymer is not included. Therefore, according to the resist composition of the present invention, substance elution during immersion exposure can be suppressed.
Since substance elution can be suppressed, by using the resist composition of the present invention, alteration of the resist film and change in the refractive index of the immersion solvent can be suppressed in immersion exposure. A resist pattern having a good shape and the like can be formed by suppressing fluctuations in the refractive index of the immersion solvent. Further, the contamination of the lens of the exposure apparatus can be reduced, and therefore, it is not necessary to take protective measures against these, and it is possible to contribute to the simplification of the process and the exposure apparatus.
These effects are particularly excellent when R ² in the polymer of the present invention contains a fluorine atom.

Moreover, the resist film formed with the resist composition of the present invention is less likely to swell with water. Therefore, a fine resist pattern can be formed with high accuracy.
Furthermore, the resist composition of the present invention has good lithography properties such as sensitivity, resolution, and etching resistance, and can form a resist pattern without any practical problems when used as a resist in immersion exposure. For example, by using the resist composition of the present invention, a fine resist pattern having a dimension of 120 nm or less can be formed, for example.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention includes a step of forming a resist film on a support using the resist composition of the present invention, a step of exposing the resist film, and an alkali developing of the resist film to form a resist pattern Forming a step.
In the present invention, the step of exposing the resist film is preferably performed by immersion exposure since the usefulness of the present invention is high.
A preferred example of the method for forming a resist pattern of the present invention is shown below.

First, after applying the resist composition of the present invention on a support with a spinner or the like, a resist film is formed by performing pre-baking (post-apply baking (PAB) treatment).
The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used. In addition, a support in which an inorganic and / or organic film is provided on the above-described substrate may be used. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include organic films such as an organic antireflection film (organic BARC) and a lower organic film in a multilayer resist method.
Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the 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 with 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 thinned and a fine pattern with a high aspect ratio can be formed. In the multilayer resist method, basically, a method of forming a two-layer structure of an upper resist film and a lower organic film (two-layer resist method), and one or more intermediate layers between the upper resist film and the lower organic film And a method of forming a multilayer structure of three or more layers (metal thin film etc.) (three-layer resist method).
After the resist film is formed, an organic antireflection film may be further provided on the resist film to form a three-layer laminate including a support, a resist film, and an antireflection film. The antireflection film provided on the resist film is preferably soluble in an alkali developer.
The steps so far can be performed using a known method. The operating conditions and the like are preferably set as appropriate according to the composition and characteristics of the resist composition to be used.

Next, the resist film obtained above is selectively exposed through a desired mask pattern.
The wavelength used for the exposure is not particularly limited, and can be performed using radiation such as an ArF excimer laser, a KrF excimer laser, or an F ₂ laser. The resist composition according to the present invention is effective for a KrF or ArF excimer laser, particularly an ArF excimer laser.
The exposure method for the resist film may be dry exposure or liquid immersion lithography. In the present invention, immersion exposure is particularly preferred.
In immersion exposure, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index larger than that of air, and exposure (immersion exposure) is performed in that state. It is an 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 formed using the resist composition for immersion exposure of the present invention 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 fluorinated inert liquid include fluorinated compounds such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as main components. Examples thereof include liquids, 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 fluorine-based 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 is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the 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, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).
In the present invention, water is preferably used as the immersion medium because the resist composition of the present invention is not particularly susceptible to the adverse effects of water and is excellent in lithography properties such as sensitivity and resist pattern shape. Water is also preferable from the viewpoints of cost, safety, environmental problems, and versatility.

Next, after the exposure process is completed, post-exposure heating (post-exposure baking (PEB)) is performed. PEB is usually applied at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 90 seconds.
Subsequently, development is performed using an alkaline developer composed of an alkaline aqueous solution, for example, a 0.1 to 10% by mass tetramethylammonium hydroxide (TMAH) aqueous solution.
After the development, water rinsing is preferably performed using pure water. The water rinsing can be performed, for example, by dropping or spraying water on the surface of the support while rotating the support to wash away the developer on the support and the resist composition dissolved by the developer.
Next, drying is performed to obtain a resist pattern in which a resist film (resist composition coating film) is patterned into a shape corresponding to the mask pattern.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
[Synthesis Example 1]
At 0 ° C. under a nitrogen atmosphere, 13.38 g (89.20 mmol) of 2,2,3,3,3-pentafluoro-1-propanol, 20.45 g (107.04 mmol) of ethyldiisopropylaminocarbodiimide hydrochloride (EDCI / HCl) ), 10 g (35.68 mmol) of [Compound 1] was added to 100 ml of a tetrahydrofuran (THF) solution of 0.19 g (1.53 mmol) of dimethylaminopyridine (DMAP), and the mixture was returned to room temperature and stirred for 12 hours. After confirming the disappearance of the raw materials by thin layer chromatography (TLC), the reaction solution was cooled to 0 ° C., and water was added to stop the reaction. Extracted 3 times with ethyl acetate. The obtained organic layer was washed twice with water, and the solvent was distilled off under reduced pressure to obtain 15 g of [Compound 2] as a colorless solid.

The obtained [Compound 2] was analyzed by NMR (internal standard: tetramethylsilane (TMS)).
¹ H-NMR (CDCl ₃ , 600 MHz): δ (ppm) = 4.64-4.57 (t, 4H, Ha), 2.70-2.48 (m, 8H, Hc), 1.76- 1.61 (d, 6H, Hb).
From the results shown above, it was confirmed that [Compound 2] had the structure shown below.

[Synthesis Example 2]
At 0 ° C. under a nitrogen atmosphere, 8.93 g (89.20 mmol) of 2,2,2-trifluoroethanol, 20.45 g (107.04 mmol) of ethyldiisopropylaminocarbodiimide hydrochloride (EDCI / HCl), dimethylaminopyridine ( 10 g (35.68 mmol) of [Compound 1] was added to 100 ml of a THF solution of 0.19 g (1.53 mmol) of DMAP), and the mixture was returned to room temperature and stirred for 12 hours. After confirming the disappearance of the raw materials by thin layer chromatography (TLC), the reaction solution was cooled to 0 ° C., and water was added to stop the reaction. Extracted 3 times with ethyl acetate. The obtained organic layer was washed twice with water, and the solvent was distilled off under reduced pressure to obtain 15 g of [Compound 13] as a colorless solid.

The obtained [Compound 13] was analyzed by NMR (internal standard: tetramethylsilane (TMS)).
¹ H-NMR (CDCl ₃ , 600 MHz): δ (ppm) = 5.78-5.71 (m, 2H, Ha), 2.72-2.44 (m, 8H, Hc), 1.71- 1.60 (d, 6H, Hb).
From the results shown above, it was confirmed that [Compound 13] had the structure shown below.

[Synthesis Example 3]
At 0 ° C. under a nitrogen atmosphere, 15.46 g (89.20 mmol) of 1,1,1,3,3,3-hexafluoro-2-propanol, 20.45 g of ethyldiisopropylaminocarbodiimide hydrochloride (EDCI / HCl) (107 0.04 mmol) and 100 g of THF solution of 0.19 g (1.53 mmol) of dimethylaminopyridine (DMAP) were added 10 g (35.68 mmol) of [Compound 1], returned to room temperature, and stirred for 12 hours. After confirming the disappearance of the raw materials by thin layer chromatography (TLC), the reaction solution was cooled to 0 ° C., and water was added to stop the reaction. Extracted 3 times with ethyl acetate. The obtained organic layer was washed twice with water, and the solvent was distilled off under reduced pressure to obtain 15 g of [Compound 14] as a colorless solid.

The obtained [Compound 14] was analyzed by NMR (internal standard: tetramethylsilane (TMS)).
¹ H-NMR (CDCl ₃ , 600 MHz): δ (ppm) = 5.78-5.71 (m, 2H, Ha), 2.72-2.44 (m, 8H, Hc), 1.71- 1.60 (d, 6H, Hb).
From the results shown above, it was confirmed that [Compound 14] had the structure shown below.

[Synthesis Example 4]
At 0 ° C. under a nitrogen atmosphere, 17.79 g (89.20 mmol) of 2,2,3,3,4,4,4-heptafluorobutanol, 20.45 g (107.20 g) of ethyldiisopropylaminocarbodiimide hydrochloride (EDCI / HCl). 04 mmol) and 10 g (35.68 mmol) of [Compound 1] were added to 100 ml of a THF solution of 0.19 g (1.53 mmol) of dimethylaminopyridine (DMAP), and the mixture was warmed to room temperature and stirred for 12 hours. After confirming the disappearance of the raw materials by thin layer chromatography (TLC), the reaction solution was cooled to 0 ° C., and water was added to stop the reaction. Extracted 3 times with ethyl acetate. The obtained organic layer was washed twice with water, and the solvent was distilled off under reduced pressure to obtain 15 g of [Compound 15] as a colorless solid.

The obtained [Compound 15] was analyzed by NMR (internal standard: tetramethylsilane (TMS)).
_{^{1 H-NMR (CDCl 3,}} 600MHz): δ (ppm) = 4.60-4.66 (t, 4H, Hd), 2.70-2.48 (m, 8H, Hc), 1.78- 1.61 (d, 6H, Hb).
From the results shown above, it was confirmed that [Compound 15] had the structure shown below.

[Monomer Synthesis Example 1 (Synthesis of [Compound 3])]
In a nitrogen atmosphere at 0 ° C., 61 g (600 mmol) of triethylamine and 64 g (418 mmol) of methyl bromoacetate were added to 300 ml of THF solution of 30 g (348 mmol) of methacrylic acid, and the mixture was returned to room temperature and stirred for 3 hours. After confirming the disappearance of the raw material by thin layer chromatography (TLC), the reaction solution was evaporated under reduced pressure. Water was added to the obtained reaction product, and the mixture was extracted 3 times with ethyl acetate. The organic layer was washed twice with water and the solvent was distilled off under reduced pressure to obtain 47 g of compound (3-1 as a colorless liquid (yield 85%)).
Next, 700 ml of a 2.38 mass% TMAH aqueous solution was added to 700 ml of a THF solution of 30 g (190 mmol) of the compound (3-1) at 0 ° C. in a nitrogen atmosphere, and the mixture was stirred at room temperature for 3 hours. After confirming the disappearance of the raw material by thin layer chromatography (TLC), the THF solvent was distilled off under reduced pressure. To the resulting aqueous reaction solution, 50 ml of 10N hydrochloric acid was added at 0 ° C. to adjust the acidity, and then extracted three times with ethyl acetate. The obtained organic layer was washed twice with water, and the solvent was distilled off under reduced pressure to obtain 26 g of Compound (3-2) as a colorless liquid (yield 95%).
Next, at 0 ° C. under a nitrogen atmosphere, 27 g (177 mmol) of 2,2,3,3,3-pentafluoro-1-propanol, 37 g (195 mmol) of ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride, dimethylaminopyridine (DMAP) ) 17 g (118 mmol) of compound (3-2) was added to 100 ml of 0.6 g (5 mmol) in THF, and the mixture was returned to room temperature and stirred for 3 hours. After confirming the disappearance of the raw materials by thin layer chromatography (TLC), the reaction solution was cooled to 0 ° C., and water was added to stop the reaction. The organic layer obtained by extraction three times with ethyl acetate was washed twice with water. The crude product obtained by distilling off the solvent under reduced pressure was purified by silica gel filtration (ethyl acetate) to obtain 19 g of [Compound 3] as a colorless liquid (yield 58%).

[Monomer Synthesis Examples 2 to 4 (Synthesis of [Compound 8] to [Compound 10])]
In the monomer synthesis example 1, in place of 2,2,3,3,3-pentafluoro-1-propanol, 2,2,2-trifluoroethanol, 1,1,1,3,3,3-hexa The following [Compound 8] to [Compound 10] are prepared in the same manner as in Monomer Synthesis Example 1 except that fluoro-2-propanol or 2,2,3,3,4,4,4-heptafluorobutanol is used. Obtained.

[Example 1]
To a three-necked flask connected with a thermometer and a reflux tube, 4.00 g (14.48 mmol) of [Compound 3] and 1.39 g (6.21 mmol) of [Compound 4] were added and 30.54 g of THF was added. And dissolved. To this solution, 3.10 mmol of [Compound 2] as a polymerization initiator was added and dissolved. This reaction solution was subjected to a polymerization reaction by heating and stirring at 80 ° C. for 6 hours under a nitrogen atmosphere, and then cooled to room temperature. The obtained reaction polymerization liquid was concentrated under reduced pressure, dropped into a large amount of n-heptane, and an operation for precipitating the polymer was performed. The precipitated polymer was filtered, washed and dried, and the target product [polymer 2.1 g of 1] was obtained.
With respect to [Polymer 1], the weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 11,000, and the molecular weight dispersity (Mw / Mn) was 1.30. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) was 1 / m = 76.5 / 23. It was 5. In addition, the ratio of —COO—CH ₂ —CF ₂ —CF ₃ introduced into the terminal of the polymer main chain was 1 mol% with respect to the whole polymer.

[Comparative Example 1]
To a three-necked flask connected with a thermometer and a reflux tube, 15.00 g (54.32 mmol) of [Compound 3], 5.21 g (23.28 mmol) of [Compound 4] were added to 114.52 g of THF. Dissolved. To this solution, 4.66 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved. This reaction solution was stirred at 80 ° C. for 6 hours under a nitrogen atmosphere and then cooled to room temperature. The obtained reaction polymerization liquid was concentrated under reduced pressure, dropped into a large amount of n-heptane, and an operation for precipitating the polymer was performed. The precipitated polymer was filtered, washed and dried, and the target product [polymer 5.6 g of 1 ′] was obtained.
With respect to [Polymer 1 ′], the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 15,000, and the molecular weight dispersity (Mw / Mn) was 1.37. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) was 1 / m = 74.5 / 25. It was 5.

[Example 2]
To a three-necked flask connected with a thermometer and a reflux tube, 3.27 g (14.48 mmol) of [Compound 8], 1.39 g (6.21 mmol) of [Compound 4] and 26.41 g of tetrahydrofuran were added. And dissolved. To this solution, 3.10 mmol of [Compound 13] as a polymerization initiator was added and dissolved. This reaction solution was subjected to a polymerization reaction by heating and stirring at 80 ° C. for 6 hours under a nitrogen atmosphere, and then cooled to room temperature. The obtained reaction polymerization liquid was concentrated under reduced pressure, dropped into a large amount of n-heptane, and an operation for precipitating the polymer was performed. The precipitated polymer compound was filtered, washed and dried, and the target product [heavy 1.9 g of Compound 2] was obtained.
With respect to [Polymer 2], the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 11,600, and the molecular weight dispersity (Mw / Mn) was 1.32. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m = 77.6 / 22. 4.

[Example 3]
4.26 g (14.48 mmol) of [Compound 9], 1.39 g (6.21 mmol) of [Compound 4] and 32.02 g of tetrahydrofuran were added to a three-necked flask connected with a thermometer and a reflux tube. And dissolved. To this solution, 3.10 mmol of [Compound 14] as a polymerization initiator was added and dissolved. This reaction solution was subjected to a polymerization reaction by heating and stirring at 80 ° C. for 6 hours under a nitrogen atmosphere, and then cooled to room temperature. The obtained reaction polymerization liquid was concentrated under reduced pressure, dropped into a large amount of n-heptane, and an operation for precipitating the polymer was performed. The precipitated polymer compound was filtered, washed and dried, and the target compound [ 2.3 g of Compound 3] was obtained.
With respect to [Polymer 3], the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 11,800, and the molecular weight dispersity (Mw / Mn) was 1.31. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) was 1 / m = 76.7 / 23. 3.

[Example 4]
To a three-necked flask connected with a thermometer and a reflux tube, 4.72 g (14.48 mmol) of [Compound 10], 1.39 g (6.21 mmol) of [Compound 4] and 34.62 g of tetrahydrofuran were added. And dissolved. To this solution, 3.10 mmol of [Compound 15] as a polymerization initiator was added and dissolved. This reaction solution was subjected to a polymerization reaction by heating and stirring at 80 ° C. for 6 hours under a nitrogen atmosphere, and then cooled to room temperature. The obtained reaction polymerization liquid was concentrated under reduced pressure, dropped into a large amount of n-heptane, and an operation for precipitating the polymer was performed. The precipitated polymer compound was filtered, washed and dried, and the target product [heavy 2.5 g of Compound 4] was obtained.
With respect to [Polymer 4], the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 11,300, and the molecular weight dispersity (Mw / Mn) was 1.34. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m = 75.5 / 24. It was 5.

[Example 5]
In a three-necked flask connected with a thermometer and a reflux tube, 13.15 g (77.33 mmol) of [Compound 5], 20.00 g (85.74 mmol) of [Compound 6], 9.12 g (38.66 mol) [Compound 7] was dissolved in 63.41 g of ethyl lactate (EL). 7 mol% of [Compound 2] was added to this solution as a polymerization initiator with respect to the molar amount of all monomers and dissolved. This reaction solution was added dropwise to 35.22 g of EL heated to 80 ° C. over 6 hours under a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization liquid was concentrated under reduced pressure, then dropped into a large amount of a methanol / water mixed solution, and an operation for precipitating the polymer was performed. The precipitated polymer was filtered, washed and dried, and the target product [ 30 g of Polymer 5] was obtained.
With respect to [Polymer 5], the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 7700, and the dispersity (Mw / Mn) was 1.23. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) was 1 / m / n = 39.3 / 41. 4 / 19.3. In addition, the ratio of —COO—CH ₂ —CF ₂ —CF ₃ introduced at the terminal of the polymer main chain was 2 mol% with respect to the whole polymer.

[Example 6]
In a three-necked flask connected with a thermometer and a reflux tube, 20.00 g (117.65 mmol) of [Compound 5], 27.53 g (117.65 mmol) of [Compound 6-2], 13.88 g (58.58 g). 83 mmol) of [Compound 7] was dissolved in 92.12 g of ethyl lactate. As a polymerization initiator, 11.7 mmol of [Compound 2] was added to this solution and dissolved. This reaction solution was added dropwise to 51.17 g of ethyl lactate heated to 80 ° C. over 6 hours under a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization liquid is concentrated under reduced pressure, then dropped into a large amount of a methanol / water mixed solution, and an operation for precipitating the polymer is performed. 45 g of [Polymer 6] was obtained.
With respect to [Polymer 6], the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 7,700, and the dispersity (Mw / Mn) was 1.23. The carbon 13 as a result of an analysis by nuclear magnetic resonance spectrum (600 MHz - ¹³ C-NMR) (ratio of the respective structural units within the structural formula (molar ratio)) is, l / m / n = 40 /40/20 Met.

[Example 7]
In a three-necked flask connected with a thermometer and a reflux tube, 20.00 g (117.65 mmol) of [Compound 5], 27.53 g (117.65 mmol) of [Compound 6], 13.88 g (58.83 mmol) [Compound 7] was dissolved in 92.12 g of ethyl lactate. As a polymerization initiator, 11.7 mmol of [Compound 13] was added to this solution and dissolved. This reaction solution was added dropwise to 51.17 g of ethyl lactate heated to 80 ° C. over 6 hours under a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization liquid is concentrated under reduced pressure, then dropped into a large amount of a methanol / water mixed solution, and an operation for precipitating the polymer is performed. 40 g of [Polymer 7] was obtained.
With respect to [Polymer 7], the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 7,600, and the dispersity (Mw / Mn) was 1.24. The carbon 13 as a result of an analysis by nuclear magnetic resonance spectrum (600 MHz - ¹³ C-NMR) (ratio of the respective structural units within the structural formula (molar ratio)) is, l / m / n = 40 /40/20 Met.

[Example 8]
In a three-necked flask connected with a thermometer and a reflux tube, 20.00 g (117.65 mmol) of [Compound 5], 27.53 g (117.65 mmol) of [Compound 6], 13.88 g (58.83 mmol) [Compound 7] was dissolved in 92.12 g of ethyl lactate. As a polymerization initiator, 11.7 mmol of [Compound 14] was added to this solution and dissolved. This reaction solution was added dropwise to 51.17 g of ethyl lactate heated to 80 ° C. over 6 hours under a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization liquid is concentrated under reduced pressure, then dropped into a large amount of a methanol / water mixed solution, and an operation for precipitating the polymer is performed. 41 g of [Polymer 8] was obtained.
With respect to [Polymer 8], the weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 7,400, and the dispersity (Mw / Mn) was 1.20. The carbon 13 as a result of an analysis by nuclear magnetic resonance spectrum (600 MHz - ¹³ C-NMR) (ratio of the respective structural units within the structural formula (molar ratio)) is, l / m / n = 40 /40/20 Met.

[Example 9]
In a three-necked flask connected with a thermometer and a reflux tube, 20.00 g (117.65 mmol) of [Compound 5], 27.53 g (117.65 mmol) of [Compound 6], 13.88 g (58.83 mmol) [Compound 7] was dissolved in 92.12 g of ethyl lactate. As a polymerization initiator, 11.7 mmol of [Compound 15] was added to this solution and dissolved. This reaction solution was added dropwise to 51.17 g of ethyl lactate heated to 80 ° C. over 6 hours under a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization liquid is concentrated under reduced pressure, then dropped into a large amount of a methanol / water mixed solution, and an operation for precipitating the polymer is performed. 45 g of [Polymer 9] was obtained.
With respect to [Polymer 9], the weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 6,900, and the dispersity (Mw / Mn) was 1.23.
The carbon 13 as a result of an analysis by nuclear magnetic resonance spectrum (600 MHz - ¹³ C-NMR) (ratio of the respective structural units within the structural formula (molar ratio)) is, l / m / n = 40 /40/20 Met.

[Comparative Example 2]
In a three-necked flask connected with a thermometer and a reflux tube, 20.00 g (117.65 mmol) of [Compound 5], 27.53 g (117.65 mmol) of [Compound 6], 13.88 g (58.83 mmol) [Compound 7] was dissolved in 169.08 g of ethyl lactate (EL). As a polymerization initiator, 11.7 mmol of 4,4′-azobis (4-cyanovaleric acid) (V-501) was added to this solution and dissolved. This reaction solution was added dropwise to 70.45 g of EL heated to 80 ° C. over 6 hours under a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization liquid was concentrated under reduced pressure, then dropped into a large amount of a methanol / water mixed solution, and an operation for precipitating the polymer was performed. 20 g of polymer 2 ′] was obtained.
With respect to [Polymer 2 ′], the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 6,500, and the dispersity (Mw / Mn) was 1.52. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n = 39.5 / 41.2 / 19.3.

[Comparative Example 3]
In a three-necked flask connected with a thermometer and a reflux tube, 20.00 g (117.65 mmol) of [Compound 5], 27.53 g (117.65 mmol) of [Compound 6-2], 13.88 g (58.58 g). 83 mmol) of [Compound 7] was dissolved in 92.12 g of ethyl lactate. As a polymerization initiator, 11.7 mmol of 4,4′-azobis (4-cyanovaleric acid) (V-501) was added to this solution and dissolved. This reaction solution was added dropwise to 51.17 g of ethyl lactate heated to 80 ° C. over 6 hours under a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization liquid is concentrated under reduced pressure, then dropped into a large amount of a methanol / water mixed solution, and an operation for precipitating the polymer is performed. The precipitated polymer compound is filtered, washed, and dried to be the target product. 35 g of [Polymer 3 ′] was obtained.
With respect to [Polymer 3 ′], the standard polystyrene-converted mass average molecular weight (Mw) determined by GPC measurement was 8,000, and the dispersity (Mw / Mn) was 1.24.
The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) was 1 / m / n = 39.8 / 38. 7 / 21.5.

[Test Example 1: Evaluation of base degradability]
[Compound 2] To 100 mg, 4 g of a mixed solution of THF / 2.38 mass% tetramethylammonium hydroxide aqueous solution (TMAH aq) = 1/1 (mass ratio) was added and stirred at 23 ° C. for 60 seconds. . The reaction solution was neutralized with 1N hydrochloric acid and developed by thin layer chromatography (TLC) (heptane: ethyl acetate = 3: 7), and it was confirmed that the ester had disappeared.
From this result, when [Compound 2] in contacting the alkaline developing solution, hydrolysis occurs by the action of the alkali developer, as described below, the both ends of the [compound 2] -O-CH ₂ CF ₂ CF It was shown that ₃ dissociated and a carboxy group was formed.

Further, when [Compound 2] was changed to [Compound 13] to [Compound 15] and the base decomposability was evaluated in the same manner as described above, [Compound 13] to [Compound 15] were also converted to [Compound 2]. It was confirmed that the same behavior was exhibited.
On the other hand, when the base decomposability was evaluated in the same manner as described above except that [Compound 2] was changed to V-601, it was confirmed that the ester was not lost. From this result, it was shown that -O-CH _{3 at the} terminal does not dissociate even when an alkaline developer is brought into contact with V-601.

[Test Example 2: Evaluation of hydrophilicity / hydrophobicity]
Each of the polymers 1, 1 ′, 2-4, 5-9, 2 ′, 3 ′ was dissolved in a mixed solvent of PGMEA / PGME = 6/4 (mass ratio) to obtain a polymer solution (solid content concentration 4 %) Was prepared.
Next, each polymer solution is applied onto an 8-inch silicon wafer subjected to hexamethyldisilazane (HMDS) treatment using a spinner, prebaked on a hot plate at 110 ° C. for 60 seconds, and dried. As a result, a polymer film having a thickness of 70 nm was formed.
Next, water was dropped on the surface of the polymer film, and contact angle (static contact angle) was measured using DROP MASTER-700 (product name, manufactured by Kyowa Interface Science Co., Ltd.). Measurement: 2 μL of water). This measured value was defined as “contact angle before development (°)”.
Each wafer after contact angle measurement was subjected to an alkali development treatment with an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution at 23 ° C. for 30 seconds, and then rinsed with pure water for 15 seconds. After being shaken off and dried, the contact angle was measured in the same manner as described above. Each measured value was defined as “contact angle after 30 s development (°)”.
These results are shown in Tables 1-2.

From the results of Table 1, the polymer of Example 1 using the compound according to the present invention having a base-dissociable group at the terminal as a radical polymerization initiator is a conventional radical polymerization start having no base-dissociable group at the terminal. It was confirmed that the polymer film formed had a larger contact angle before development and higher hydrophobicity than the polymer of Comparative Example 1 obtained in the same manner except that the agent was used.
Moreover, as for the polymer film formed in Examples 1-4, this contact angle fell 10 degrees or more after image development, and it has confirmed that hydrophilicity improved greatly by contact with a developing solution.
Similarly, from the results in Table 2, the polymers of Examples 5 to 9 using the compound according to the present invention having a base dissociable group at the terminal as a radical polymerization initiator each have a base dissociable group at the terminal. Compared with the polymers of Comparative Examples 2 and 3 obtained in the same manner except that a conventional radical polymerization initiator is used, the contact angle before development of the formed polymer film is large and the hydrophobicity is high. It could be confirmed.
In addition, in all the polymer films formed in Examples 5 to 9, the contact angle decreased by 10 ° or more after development, and it was confirmed that the hydrophilicity was greatly improved by contact with the developer.
From these results, when the polymer of the present invention is blended with a resist composition, the resist film formed using the resist composition also has a property that the hydrophobicity before development is high and the hydrophilicity is improved after development. You can see that
Since the resist film before development is highly hydrophobic, the resist composition of the present invention containing the polymer of the present invention improves both the scan followability and the elution reduction effect during immersion scan exposure. It is expected. Further, since the hydrophilicity of the resist film is increased after development, an improvement in the effect of reducing defects is also expected.

[Examples 10 to 14]
A positive resist composition was prepared by mixing the components shown in Table 3 below.

In Table 3, each abbreviation indicates the following, and the numerical value in [] is the blending amount (part by mass).
(A) -5: [Polymer 5].
(A) -6: [Polymer 6].
(A) -7: [Polymer 7].
(A) -8: [Polymer 8].
(A) -9: [Polymer 9].
(B) -1: 4-methylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate.
(D) -1: Tree n-pentylamine.
(E) -1: salicylic acid.
(C ′)-1: a polymer compound represented by the following formula (C ′)-1 (l / m = 75/25, molecular weight 23900, dispersity 1.5)
(S) -1: γ-butyrolactone.
(S) -2: Mixed solvent of PGMEA / PGME = 6/4 (mass ratio).

[Resist pattern formation]
An organic antireflection film composition “ARC29A” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto a 12-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a film thickness of 89 nm was formed.
Then, the positive resist compositions of Examples 10 to 14 are applied on the antireflection film using a spinner, and prebaked (PAB) is performed on a hot plate at 110 ° C. for 60 seconds. Then, a resist film having a film thickness of 100 nm was formed by drying.
Next, an ArF immersion exposure apparatus NSR-S609B (manufactured by Nikon Corporation; NA (numerical aperture) = 1.07, σ0.97) is applied to the resist film through the mask pattern. , ArF excimer laser (193 nm) was selectively irradiated.
Subsequently, PEB processing was performed at 100 ° C. for 60 seconds, and further development processing was performed at 23 ° C. with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds.
As a result, in each example, a line and space pattern having a line width of 60 nm and a pitch of 110 nm was formed on the resist film.
In addition, the following defect evaluation was performed without performing the rinse process after image development.

[Defect evaluation]
About the line part (unexposed part) of the obtained resist pattern, the number of defects was measured by a surface defect observation apparatus “KLA2371” manufactured by KLA Tencor. The results are shown in Table 4.

  As shown in Table 4, even in the formation of the resist pattern by topcoat-less immersion exposure, the number of defects is less than 1000, and the positive resist compositions of Examples 10 to 14 according to the present invention are extremely effective in reducing defects. It was found to be excellent.

It is a figure explaining advancing angle ((theta) ₁ ), receding angle ((theta) ₂ ), and falling angle ((theta) ₃ ).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Droplet, 1a ... Lower end, 1b ... Upper end, 2 ... Plane, [theta] ₁ ... Advance angle, [theta] ₂ ... Receding angle, [theta] ₃ ... Falling angle

Claims (18)

A polymer having a group represented by the following general formula (i-1) at at least one terminal of the main chain.

[Wherein, R ¹ represents an alkylene group which may have a substituent; R ² represents —O—R ² in the formula as a base dissociable group that dissociates by the action of an alkali developer. Organic group. ] The polymer according to claim 1, which is a radical polymer obtained by radical polymerization using a radical polymerization initiator comprising a compound represented by the following general formula (I).

[Wherein, R ¹ represents an alkylene group which may have a substituent; R ² represents —O—R ² in the formula as a base dissociable group that dissociates by the action of an alkali developer. Organic group. ] The polymer according to claim 1, wherein R ² is a hydrocarbon group having an electron withdrawing group. The polymer according to any one of claims 1 to 3, wherein R ² is a hydrocarbon group having a fluorine atom. The compound represented by the following general formula (I).

[Wherein, R ¹ represents an alkylene group which may have a substituent; R ² represents —O—R ² in the formula as a base dissociable group that dissociates by the action of an alkali developer. Organic group. ] The compound according to claim 5, wherein R ² is a hydrocarbon group having an electron withdrawing group. The compound according to claim 5 or 6, wherein R ² is a hydrocarbon group having a fluorine atom.   The radical polymerization initiator which consists of a compound as described in any one of Claims 5-7.   The resist composition containing the polymer as described in any one of Claims 1-4.   A chemically amplified resist composition comprising a base material component (A) whose solubility in an alkaline developer is changed by the action of an acid, and an acid generator component (B) that generates an acid upon exposure, wherein the base material The resist composition in which a component (A) contains the base-material component (A1) which consists of a polymer as described in any one of Claims 1-4.   The base material component (A ') whose solubility in an alkaline developer is changed by the action of an acid, the acid generator component (B') that generates an acid upon exposure, and the composition according to any one of claims 1 to 4. A resist composition containing an additive component (C ′) comprising a polymer.   The resist composition according to any one of claims 9 to 11, wherein the polymer has a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.   The resist composition according to claim 12, wherein the polymer has a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.   The resist composition according to claim 12 or 13, wherein the polymer has a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.   The resist composition as described in any one of Claims 9-14 in which the said polymer has a structural unit which has a base dissociable group dissociated by the effect | action of an alkali developing solution.   Furthermore, the resist composition as described in any one of Claims 9-15 containing a nitrogen-containing organic compound component (D).   The resist composition according to any one of claims 9 to 16, which is for immersion exposure.   The process of forming a resist film using the resist composition as described in any one of Claims 9-17 on a support body, the process of exposing the said resist film, and alkali-developing the said resist film, and developing a resist pattern A resist pattern forming method including a step of forming a film.

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