JP5114286B2 - Positive resist composition, resist pattern forming method, and polymer compound - Google Patents

Description

  The present invention relates to a novel polymer compound that can be used as a base component of a positive resist composition, a positive resist composition containing the polymer compound, and a resist pattern forming method using the positive resist composition.

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.
A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.
In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has been rapidly progressing due to advances in lithography technology.
As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. In addition, studies have been made on F ₂ excimer lasers, electron beams, EUV (extreme ultraviolet rays), X-rays, and the like having shorter wavelengths than these excimer lasers.

Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions.
As a resist material satisfying such requirements, a chemically amplified resist composition containing a base material component 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. ing.
For example, as a positive chemically amplified resist composition, a composition containing a resin component (base resin) whose solubility in an alkaline developer is increased by the action of an acid and an acid generator component is generally used. Yes. When such a resist film formed using the resist composition is selectively exposed at the time of forming the resist pattern, an acid is generated from the acid generator in the exposed portion, and the alkali developer of the resin component is generated by the action of the acid. And the exposed area becomes soluble in an alkaline developer.
Currently, as a resist base resin used in ArF excimer laser lithography and the like, a resin having a constitutional unit derived from (meth) acrylic acid ester (acrylic resin) because of its excellent transparency near 193 nm ) And the like are generally used (see, for example, Patent Document 1).
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.
JP 2003-241385 A

In the future, as further progress in lithography technology and expansion of application fields are expected, there is an increasing demand for new materials that can be used for lithography applications. In particular, as the resist pattern is further miniaturized, there is a novel material that has excellent lithography characteristics, for example, a pattern that can be obtained in a good shape even when a fine pattern having a size of 100 nm or less is formed at a narrow pitch. It has been demanded.
The present invention has been made in view of the above circumstances, and is a novel polymer compound that can be used as a base component of a positive resist composition suitable for forming a fine pattern, and a positive polymer containing the polymer compound. It is an object to provide a resist pattern forming method using the positive resist composition and the positive resist composition.

The present inventors propose the following means in order to solve the above problems.
That is, the first aspect of the present invention is a positive type containing a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure. It is a resist composition, Comprising: The said base material component (A) is the structural unit (a01) represented by the following general formula (a0-1), and the structural unit (A0-3) represented by the following general formula (a0-3) ( a positive resist composition comprising a polymer compound (A1) having a03).

［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、複数のＲはそれぞれ同じであっても異なっていても良く；Ｒ^１は炭素数２以上のアルキル基であり；Ｒ^２およびＲ^３はそれぞれ独立してアルキル基であり、Ｒ^２およびＲ^３は相互に結合して炭素数８以上の単環構造を形成しており；Ｒ^４は置換基を有していても良い炭素数１０以下の鎖状または単環式のヒドロキシアルキル基である。］

[Wherein, R is a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group, and a plurality of R may be the same or different; R ¹ is an alkyl group having 2 or more carbon atoms; R ² and R ³ are each independently an alkyl group, R ² and R ³ are bonded to each other to form a monocyclic structure having 8 or more carbon atoms; R ⁴ has a substituent. It may be a linear or monocyclic hydroxyalkyl group having 10 or less carbon atoms. ]

  The second aspect of the present invention includes a step of forming a resist film on a support using the positive resist composition of the first aspect of the present invention, 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.

  Moreover, the 3rd aspect of this invention has the structural unit (a01) represented by the following general formula (a0-1), and the structural unit (a03) represented by the following general formula (a0-3). It is a high molecular compound characterized by the above.

［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、複数のＲはそれぞれ同じであっても異なっていても良く；Ｒ^１は炭素数２以上のアルキル基であり；Ｒ^２およびＲ^３はそれぞれ独立してアルキル基であり、Ｒ^２およびＲ^３は相互に結合して炭素数８以上の単環構造を形成しており；Ｒ^４は置換基を有していても良い炭素数１０以下の鎖状または単環式のヒドロキシアルキル基である。］

[Wherein, R is a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group, and a plurality of R may be the same or different; R ¹ is an alkyl group having 2 or more carbon atoms; R ² and R ³ are each independently an alkyl group, R ² and R ³ are bonded to each other to form a monocyclic structure having 8 or more carbon atoms; R ⁴ has a substituent. It may be a linear or monocyclic hydroxyalkyl group having 10 or less carbon atoms. ]

In the present specification and claims, “structural unit” means a monomer unit (monomer unit) constituting a resin component (polymer).
“Exposure” is a concept that includes radiation exposure in general.
An “acid-dissociable group” is an organic group that can be dissociated by the action of an acid.
An “aliphatic cyclic group” is a monocyclic group or polycyclic group having no aromaticity.
The “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
The “lower alkyl group” means an alkyl group having 1 to 5 carbon atoms.

  According to the present invention, a novel polymer compound that can be used as a base component of a positive resist composition suitable for forming a fine pattern, a positive resist composition containing the polymer compound, and the positive resist A resist pattern forming method using the composition can be provided.

≪Positive resist composition≫
The positive resist composition of the present invention comprises a base component (A) (hereinafter referred to as component (A)) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator that generates an acid upon exposure. Contains component (B) (hereinafter referred to as component (B)). Here, the “base material component” is an organic compound having a film forming ability.
In such a positive resist composition, when radiation is irradiated (exposed), an acid is generated from the component (B), and the solubility of the component (A) in an alkaline developer is increased by the action of the acid. Therefore, in the formation of the resist pattern, when selective exposure is performed on the resist film obtained using the positive resist composition, the solubility of the resist film in the alkaline developer in the exposed portion increases. Since the solubility of the unexposed portion in the alkaline developer does not change, a resist pattern can be formed by performing alkali development.

<(A) component>
The component (A) is a polymer compound (A1) having the structural unit (a01) represented by the general formula (a0-1) and the structural unit (a03) represented by the general formula (a0-3). ). Hereinafter, each structural unit will be described in detail.

・ Structural unit (a01)
The structural unit (a01) is represented by the general formula (a0-1).
In formula (a0-1), R represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group.
The lower alkyl group for R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, or an isobutyl group. Tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
The halogenated lower alkyl group for R is a group in which part 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.
R is preferably a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group, and most preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability.

In formula (a0-1), R ¹ is an alkyl group having 2 or more carbon atoms.
The alkyl group for R ¹ may be linear, branched or cyclic.
When the alkyl group is linear or branched, it preferably has 2 to 5 carbon atoms, more preferably an ethyl group or a propyl group, and most preferably an ethyl group.
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 groups in which one hydrogen atom has been removed from a polycycloalkane such as monocycloalkane, 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 ¹ is preferably linear or branched.

In formula (a0-1), R ² and R ³ are each independently an alkyl group, and R ² and R ³ are bonded to each other to form one monocyclic structure. In this case, a carbon atom to which R ¹ , R ² and R ³ are bonded together with R ² and R ³ forms a cyclic alkyl group. The cyclic alkyl group has 8 to 12 carbon atoms. Preferably, it has 8 to 10 carbon atoms, and most preferably has 8 to 9 carbon atoms. And, as the cyclic alkyl group, those carbon atoms between the terminal of R ² and R ³ are formed by bond.

  Specific examples of preferred structural unit (a01) include those represented by the following formulae.

  The structural unit (a01) contained in the polymer compound (A1) may be one type or two or more types.

When an acid is generated from the component (B) by exposure when the polymer compound (A1) is blended with the component (B) in the positive resist composition, R in the structural unit (a01) is generated by the action of the acid. ¹ , the bond between the carbon atom to which R ² and R ³ are bonded and the oxygen atom bonded to the carbon atom is broken, and the general formula “—C (R ¹ ) (R ² ) (R ³ ) (wherein R ¹ , R ² and R ³ are the same as defined above), respectively. That is, the group represented by the general formula “—C (R ¹ ) (R ² ) (R ³ )” has an acid dissociation property that is dissociated by the action of an acid generated from the component (B), Has an alkali dissolution inhibiting property that makes the entire polymer compound (A1) insoluble in an alkali developer.

・ Structural unit (a03)
The structural unit (a03) is represented by the general formula (a0-3).
R in the formula (a0-3) is the same as R in the formula (a0-1).

In formula (a0-3), R ⁴ represents a chain or monocyclic hydroxyalkyl group having 10 or less carbon atoms, which may have a substituent.
The linear hydroxyalkyl group of R ⁴ may be either linear or branched, and one or more hydrogen atoms of the linear or branched alkyl group having 10 or less carbon atoms are hydroxyl groups. The substituted one can be exemplified. The linear or branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 4 to 8 carbon atoms, and most preferably 5 to 7 carbon atoms.

Examples of the monocyclic hydroxyalkyl group represented by R ⁴ include those in which one or more hydrogen atoms of a monocyclic alkyl group having 10 or less carbon atoms are substituted with a hydroxyl group. Among these, those having 4 to 10 carbon atoms constituting the ring are preferable, those having 5 to 8 are more preferable, and those having 5 to 7 are most preferable.

The number of hydroxyl groups in the linear or monocyclic hydroxyalkyl group of R ⁴ is preferably 1 or 2, and more preferably 1.
The bonding position of the hydroxyl group in R ⁴ is not particularly limited, but is directly bonded to the oxygen atom (—O—) adjacent to the carbonyl group (—C (═O) —) in formula (a0-3). It is preferably bonded to a carbon atom other than carbon atoms, and more preferably bonded to a carbon atom adjacent to the carbon atom directly bonded to the oxygen atom.

In R ⁴ , “may have a substituent” means a hydrogen atom of a chain or monocyclic hydroxyalkyl group having 10 or less carbon atoms (excluding a hydrogen atom constituting a hydroxyl group). It means that a part or all of them are substituted with a substituent, or a part of carbon atoms of the hydroxyalkyl group may be substituted with a substituent.

Examples of the substituent with which a hydrogen atom may be substituted include a halogen atom, an alkyl group, a halogenated alkyl group, and an alkoxy group.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As said alkyl group, a C1-C3 thing is preferable and a methyl group, an ethyl group, n-propyl group, or an isopropyl group is mentioned.
Examples of the halogenated alkyl group include those in which part or all of the hydrogen atoms of the alkyl group as the substituent in R ⁴ are substituted with a halogen atom. The halogen atom is the same as the halogen atom as a substituent in R ⁴ .
As said alkoxy group, a C1-C3 alkoxy group is preferable, and a methoxy group, an ethoxy group, n-propoxy group, and iso-propoxy group are mentioned.
The number of substituents with which the hydrogen atom is substituted is not particularly limited, but is preferably 0 to 2, more preferably 0 or 1, and most preferably 0.

Examples of the substituent with which the carbon atom may be substituted include a hetero atom, and as the hetero atom, an oxygen atom and a sulfur atom are preferable, and an oxygen atom is particularly preferable.
The carbon atom substituted with the substituent may be either a carbon atom constituting a chain structure or a carbon atom constituting a ring structure, but is preferably a carbon atom constituting a ring structure.
The number of substituents with which the carbon atom is substituted is preferably 0 to 2, and more preferably 0 or 1.

In the present invention, R ⁴ is preferably a monocyclic hydroxyalkyl group, and has no substituent or a monocyclic hydroxyalkyl group in which a carbon atom constituting the ring structure is substituted with a heteroatom. More preferably, it is most preferably a monocyclic monohydroxyalkyl group having no substituent or having a ring structure substituted with a heteroatom.

  Specific examples of preferred structural unit (a03) include those represented by the following formulae.

  The structural unit (a03) contained in the polymer compound (A1) may be one type or two or more types.

The polymer compound (A1) may be a polymer composed only of the structural unit (a01) and the structural unit (a03), or may be a copolymer including other structural units.
In the polymer compound (A1), the proportion of the structural unit (a01) is preferably 10 to 80 mol%, and preferably 30 to 75 mol% with respect to all the structural units constituting the polymer compound (A1). The amount is more preferable, and the amount of 40 to 70 mol% is most preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when a resist composition is obtained, and in particular, the resolution, pattern shape, and line of the positive resist composition containing the polymer compound (A1). Lithographic properties such as edge roughness and dissolution contrast are improved. Moreover, the balance with another structural unit can be taken by making it below an upper limit.

  In the polymer compound (A1), the proportion of the structural unit (a03) is preferably 5 to 50 mol% with respect to all the structural units constituting the polymer compound (A1). Is more preferable, and an amount of 5 to 25 mol% is most preferable. By setting it to the lower limit value or more, the resolution, pattern shape, lithography properties such as line edge roughness, and dissolution contrast of the positive resist composition containing the polymer compound (A1) are improved. By setting the upper limit value or less, it is possible to balance with other structural units.

When the polymer compound (A1) of the present invention is a copolymer containing a structural unit other than the structural unit (a01) and the structural unit (a03), the structural unit (a01) and the structural unit (a03) The other structural unit is not particularly limited, and may be any structural unit that has been used for the base resin for chemically amplified resists. Specific examples of preferable structural units include structural units derived from acrylate esters such as the following structural units (a1) to (a3).
Of these, the polymer compound (A1) preferably further has a structural unit (a2) in addition to the structural unit (a01) and the structural unit (a03).
Here, in the present specification and claims, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. 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 is a carbon atom to which a carbonyl group is bonded unless otherwise specified.
In the acrylate ester, examples of the lower alkyl group and halogenated lower alkyl group as a substituent at the α-position include those similar to the lower alkyl group and halogenated lower alkyl group in R in the formula (a0-1). It is done.
The α-position of the acrylate ester is preferably a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, more preferably a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group. From the viewpoint of industrial availability, a hydrogen atom or a methyl group is most preferable.

・ 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.
The lactone cyclic group in the structural unit (a2) has an affinity for a developer containing water or a polymer containing the resist film when the polymer compound (A1) is used for forming a resist film. It is effective in improving the sex.

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 ″, wherein 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 formulas 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 (a01).
The lower alkyl group for R ′ is the same as the lower alkyl group for R in the structural unit (a01).
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 in which one or more hydrogen atoms are removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group. 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. 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.

  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 (a2) -3) At least 1 sort (s) selected from the group which consists of a structural unit represented by 3) is more preferable. 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.

As the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
In the polymer compound (A1), the proportion of the structural unit (a2) is preferably from 5 to 60 mol%, more preferably from 10 to 50 mol%, based on the total of all the structural units constituting the polymer compound (A1). Preferably, 20-50 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 (a1)
The polymer compound (A1) has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group that does not fall under the structural unit (a01) as long as the effects of the present invention are not impaired. You may do it.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire polymer compound (A1) insoluble in an alkali developer before dissociation, and is dissociated by an acid to cause this high It increases the solubility of the molecular compound (A1) in the alkaline developer, and what has been proposed as an acid dissociable, dissolution inhibiting group for a base resin for a chemically amplified resist can be used. .

In the polymer compound (A1), as the structural unit (a1), one type of structural unit may be used alone, or two or more types may be used in combination.
In the polymer compound (A1), the proportion of the structural unit (a1) is preferably 10 mol% or less, more preferably 5 mol% or less with respect to all the structural units constituting the polymer compound (A1). Most preferred.

・ Structural unit (a3)
The polymer compound (A1) includes a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group that does not fall under the structural unit (a03) as long as the effects of the present invention are not impaired. You may have.
When the polymer compound (A1) has the structural unit (a3), the hydrophilicity of the polymer compound (A1) is increased, the affinity with the developer is increased, and the alkali solubility in the exposed area is improved. Contributes to improved resolution.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a polycyclic aliphatic hydrocarbon group (polycyclic group). 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.

  Preferred examples of the structural unit (a3) include a structural unit represented by the following formula (a3-1), a structural unit represented by (a3-2), and a structural unit represented by (a3-3). It is done.

［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 as defined 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 3rd 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.

In the polymer compound (A1), as the structural unit (a3), one type of structural unit may be used alone, or two or more types may be used in combination.
In the polymer compound (A1), the proportion of the structural unit (a3) is preferably 10% by mole or less, more preferably 5% by mole or less, based on all the structural units constituting the polymer compound (A1). Most preferred.

・ Structural unit (a4)
The polymer compound (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. 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 a non-acid-dissociable aliphatic polycyclic group is preferable. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the resin component of the resist composition.
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 those represented by the following general formulas (a4-1) to (a4-5).

［式中、Ｒは前記と同じである。］

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

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

In the present invention, the polymer compound (A1) is preferably a copolymer having the structural units (a01), (a2) and (a03). Examples of the copolymer include a copolymer composed of structural units (a01), (a2) and (a03), a copolymer composed of structural units (a01), (a2), (a03) and (a4), Examples thereof include a copolymer composed of units (a01), (a2), (a03) and (a1), a copolymer composed of structural units (a01), (a2), (a03) and (a3).
As the polymer compound (A1), a copolymer having three types of structural units respectively represented by the following formula (A1-1) or (A1-2) is particularly preferable.

［式中、Ｒは前記と同じであり、複数のＲはそれぞれ同じであっても異なっていてもよい。Ｒ^１０はそれぞれ独立に低級アルキル基である。］

[Wherein, R is the same as defined above, and a plurality of R may be the same or different. R ¹⁰ is each independently a lower alkyl group. ]

In formulas (A1-1) and (A1-2), R is the same as described above, and a plurality of R may be the same or different, and among them, may be a hydrogen atom or a methyl group. preferable.
R ¹⁰ is a lower alkyl group, which is the same as the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group.

The polymer compound (A1) is a monomer derived from the target structural unit, such as azobisisobutyronitrile (AIBN), dimethyl-2,2′-azobis (2-methylpropionate (manufactured by Wako Pure Chemical Industries, Ltd.). : V-601) can be obtained by polymerization by a known radical polymerization using a radical polymerization initiator.
Further, in the polymer compound (A1), a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination in the above polymerization. , -C at the end of the polymer main chain _{(CF 3)} may be introduced 2 -OH group. As described above, a copolymer in which a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is introduced into the terminal of the polymer main chain has reduced development defects and LER (line edge roughness: This is effective for reducing unevenness.

Although the mass mean molecular weight (Mw) (polystyrene conversion reference | standard by gel permeation chromatography) of a high molecular compound (A1) is not specifically limited, 2000-50000 are preferable, 3000-30000 are more preferable, 5000- 20000 is 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. 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.

In the component (A), the polymer compound (A1) may be used alone or in combination of two or more.
The proportion of the polymer compound (A1) in the component (A) is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and 100% by mass with respect to the total mass of the component (A). Good.

Component (A) is a “base component whose solubility in an alkaline developer is increased by the action of an acid” (hereinafter referred to as component (A2)) other than the polymer compound (A1) as long as the effects of the present invention are not impaired. May be contained).
The component (A2) is not particularly limited, and many conventionally known base components for chemically amplified positive resist compositions (for example, for ArF excimer laser, for KrF excimer laser (preferably A base resin such as ArF excimer laser) may be arbitrarily selected and used. For example, the base resin for ArF excimer laser includes those having the structural unit (a1) as an essential structural unit and optionally further including the structural units (a2) to (a4).
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

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

<(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、置換基を有していても良いアルキル基、ハロゲン化アルキル基、アリール基、またはアルケニル基を表し；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 to each other to form a ring together with the sulfur atom in the formula; R ⁴ ″ may be an optionally substituted alkyl group, halogenated alkyl group, aryl group, or alkenyl group; And at least one of R ¹ ″ to 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 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 groups, alkoxy groups 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, an ethyl group, a propyl group, an n-butyl group, or a 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, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted with 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.

When any two of R ¹ ″ to R ³ ″ in the 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 include the same aryl groups as R ¹ ″ to R ³ ″.

R ⁴ ″ represents an alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
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 preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.

Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. 50 to 100% is preferable, and 100% is most preferable. The higher the halogenation rate, the better the acid strength.

The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.

In the above R ⁴ ″, “optionally substituted” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one or two or more.

Examples of the substituent include, for example, a halogen atom, a hetero atom, an alkyl group, a formula: XQ ^1- [where Q ¹ is a divalent linking group containing an oxygen atom, and X has a substituent. And a hydrocarbon group having 3 to 30 carbon atoms. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described above for R ⁴ ″ as the halogen atom and alkyl group in the halogenated alkyl group.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

X-Q 1 ^- In the group represented by, Q ¹ represents a divalent linking group containing an oxygen atom.
Q ¹ may contain an atom other than an oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —O—C (═O) — , R ^{91 to} R ⁹³ are each independently an alkylene group.) And the like.
The alkylene group for R ^{91 to} R ⁹³ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C ( _{CH 3) (CH 2 CH 3} ) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —CH (CH ₂ CH ₃ ) CH ₂ —, Alkylethylene groups such as —CH (CH ₂ CH ₃ ) CH ₂ —; trimethylene group (n-propylene group) [—CH ₂ CH ₂ CH ₂ —]; —CH (CH ₃ ) CH ₂ CH ₂ —, —CH _{2 CH (CH 3) CH 2} - alkyl trimethylene group and the like; Toramechiren group _{[-CH 2 CH 2 CH 2 CH} 2 -]; - CH (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; penta And methylene group [—CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —] and the like.
Q ¹ is preferably a divalent linking group containing an ester bond or an ether bond, and in particular, an ester bond (—C (═O) —O—), —R ⁹¹ —O—, —R ⁹² —O—. C (═O) — or —C (═O) —O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by XQ ^1- , the hydrocarbon group of X may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, still more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X, the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted by a substituent containing a hetero atom, and the hydrogen atom constituting the aliphatic hydrocarbon group May be substituted with a substituent containing a hetero atom.
The “heteroatom” in X is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon 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, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henocosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms have been removed from a monocycloalkane; a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include the following formulas (L1) to (L5), (S1) to (S4), and the like.

［式中、Ｑ”は炭素数１〜５のアルキレン基、−Ｏ−、−Ｓ−、−Ｏ−Ｒ^９４−または−Ｓ−Ｒ^９５−であり、Ｒ^９４およびＲ^９５はそれぞれ独立に炭素数１〜５のアルキレン基であり、ｍは０または１の整数である。］

[Wherein, Q ″ is an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ — or —S—R ⁹⁵ —, and R ⁹⁴ and R ⁹⁵ are each independently carbon. An alkylene group of 1 to 5 and m is an integer of 0 or 1.]

In the formula, examples of the alkylene group for Q ″, R ⁹⁴ and R ⁹⁵ include the same alkylene groups as those described above for R ^{91 to} R ⁹³ .
In these aliphatic cyclic groups, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
As said alkyl group, a C1-C5 alkyl group is preferable, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, n-butyl group, and a tert- butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

In the present invention, X is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from the polycycloalkane, the above (L2) to (L5), (S3) to (S4), and the like.

"- if having a substituent represented by, ^{R 4} is ^{X-Q 1"} is ^{X-Q 1 -Y 1 - R} 4 in the ^{Formula, Q} 1, X are as defined above, ^{Y 1} is a substituted group Or an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. It is preferable that it is group represented by this. That is, the anion moiety is preferably represented by the general formula “XQ ¹ -Y ¹ —SO ₃ ^— [wherein Q ¹ , X and Y ¹ are as defined above]”.

In the group represented by XQ ¹ -Y ^1- , the alkylene group for Y ¹ includes the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^1, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - C H ₂ CH ₂ CF ₂ CF ₂ —, —CH (CF ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CF ₃ ) CH ₂ —, —CH (CF ₃ ) CH (CF ₃ ) —, —C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ¹ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

The alkylene group or fluorinated alkylene group may have a substituent. An alkylene group or a fluorinated alkylene group has a “substituent” means that part or all of the hydrogen atom or fluorine atom in the alkylene group or fluorinated alkylene group is substituted with an atom or group other than a hydrogen atom and a fluorine atom. Means that
Examples of the substituent that the alkylene group or fluorinated alkylene group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl 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 formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate, triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its 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) phenyl sulphonium trifluoromethane sulphonate, its heptafluoropropane sulphonate or its nonafluorobutane sulphonate; 1-phenyltetrahydrothiophenium trifluoromethane sulphonate, its heptafluoropropane sulphonate 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.
Further, methanesulfonate anion moiety of these onium salts, n- propanesulfonate, n- butane sulfonate, and alkyl sulfonates, such as n- octane sulfonate, the formula _{^{"X-Q 1 -Y 1 -SO 3}} - " in Onium salts substituted with the groups represented 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 and 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, preferably 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 ″, as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid 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). The anion part represented by the general formula (b-3) or (b-4) and the like.

  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), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. 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 as those having no substituent of R ³⁵ .
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.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO2004 / 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, as the component (B), triaryl sulfonium ion and cation portion, the formula _{^{"X-Q 1 -Y 1 -SO 3}} - " onium salt-based acid group represented anion portion in It is preferable to use a generator.
The content of the component (B) in the positive resist composition of the present invention is preferably 0.5 to 50 parts by mass, more preferably 1 to 30 parts by mass, and 2 to 20 parts per 100 parts by mass of the component (A). Part by mass is most preferred. 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>
In the positive resist composition of the present invention, a nitrogen-containing organic compound (D) (hereinafter, referred to as “component (D)”) is further added as an optional component in order to improve the resist pattern shape, stability with time, and the like. Can be blended.
Since a wide variety of components (D) have already been proposed, 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, etc .; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amine, tri -n- octanol amine, stearyl diethanolamine, alkyl alcohol amines such as lauryl diethanolamine. Among these, a C5-C10 trialkylamine and alkyl alcohol amine are preferable, and tri-n-pentylamine, diethanolamine, and stearyl diethanolamine are particularly 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 of the present invention comprises an organic carboxylic acid, a phosphorus oxo acid, and derivatives thereof as optional components for the purpose of preventing sensitivity deterioration and improving the resist pattern shape, retention stability over time, etc. At least one compound (E) selected from the group (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of 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 the 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 used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

  If desired, the resist composition of the present invention may further contain miscible additives such as an additional resin for improving the performance of the resist film, a surfactant for improving coatability, a dissolution inhibitor, a plasticizer. An agent, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

<Organic solvent (S)>
The resist composition 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. Conventionally, any one of 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 or 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;
Aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. be able to.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL 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.
The amount of the component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. -20% by mass, preferably 5-15% by mass.

The positive resist composition of the present invention is a novel one that has not been known so far.
In addition, according to the positive resist composition of the present invention, pre-baking (post-apply baking (PAB)) and PEB (post-exposure heating), particularly PEB, can be performed at a lower temperature than conventional methods in the resist pattern forming method described later. And a fine resist pattern can be formed on the support with high resolution. Resist with good lithography characteristics such as improved mask reproducibility (for example, mask linearity) when forming a resist pattern, reduced line edge roughness (LER), and increased roundness of the contact hole pattern A pattern can be formed.
Here, LER means roughness of the resist pattern side wall surface. LER is a cause of adverse effects on the formation of fine semiconductor elements, etc., because it may cause distortion of the hole pattern in the hole pattern and deterioration of the resist pattern shape such as variation in line width in the line and space pattern. There is a need for improvement.
The reason why the above effect is obtained is not clear, but by performing PEB or the like at a lower temperature than conventional, diffusion of the component (B) in the resist film is suppressed, so that the acid generated in the exposure region It is presumed that the diffusion to the unexposed area is suppressed, and as a result, the difference in solubility (dissolution contrast) in the alkaline developer between the unexposed area and the exposed area is improved. In addition, since PEB or the like can be performed at a lower temperature than conventional, the general formula “—C (R ¹ ) (R ² ) (R ³ ) (in the formula, R ¹ ) in the structural unit (a01) , R ² and R ³ are the same as defined above.) ”Is a group represented by the above-mentioned acid dissociable, dissolution inhibiting group in the component (a1) due to the action of the acid generated from the component (B). Since it dissociates easily even at a low temperature, it is presumed that the solubility of the polymer compound (A1) in an alkaline developer increases at a lower temperature than before. Furthermore, since the structural unit (a03) has a smaller molecular size than the conventional (a3) component having a polycyclic aliphatic hydrocarbon group such as an adamantyl group, it is suitable for forming a fine pattern. Guessed. Thus, when the polymer compound (A1) has the structural unit (a01), it is possible to lower the temperature of PEB and the like, and the structural unit (a03) makes it easy to form a fine pattern. It is presumed that the above effect can be obtained by synergistically exhibiting the above action.

≪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 positive 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. Forming a pattern.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the positive resist composition is coated on a support with a spinner or the like, and prebaked (post-apply bake (PAB)) at 40 to 120 ° C. under a temperature condition of 60 to 150 ° C., preferably 70 to 100 ° C. Second, preferably 60 to 90 seconds, and selectively exposed to ArF excimer laser light through a desired mask pattern by, for example, an ArF exposure apparatus, and then 50 to 150 ° C., preferably 50 to 80 ° C. Under temperature conditions, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process. In this way, a resist pattern faithful to the mask pattern can be obtained.

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.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).

The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation. The resist composition is effective for KrF excimer laser, ArF excimer laser, EB or EUV, particularly ArF excimer laser.

The exposure of the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be immersion exposure.
In immersion exposure, as described above, the portion between the lens, which has been conventionally filled with an inert gas such as air or nitrogen, and the resist film on the wafer is refracted larger than the refractive index of air. The exposure is performed in a state filled with a solvent having a high rate (immersion medium).
More specifically, in the immersion exposure, a solvent (immersion medium) having a refractive index larger than the refractive index of air between the resist film obtained as described above and the lowermost lens of the exposure apparatus. And in that state, it can be carried out by exposing through a desired mask pattern (immersion exposure).
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 exposed by the immersion exposure is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorine-based inert liquid include a fluorine-based compound such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as a main component. 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.).

  The positive resist composition of the present invention can also be applied to a double exposure method or a double patterning method.

≪Polymer compound≫
The polymer compound of the present invention has a structural unit (a01) represented by the general formula (a0-1) and a structural unit (a03) represented by the general formula (a0-3).
The description of the polymer compound of the present invention is the same as the description of the polymer compound (A1) cited as the component (A) of the positive resist composition of the present invention.

As described above, the polymer compound (A1) is a monomer derived from the target structural unit, such as azobisisobutyronitrile (AIBN) or dimethyl-2,2′-azobis (2-methylpropionate). It can obtain by making it superpose | polymerize by the well-known radical polymerization etc. which used radical polymerization initiators.
For example, the monomer that derives the structural unit (a01) includes the compound (01) represented by the following general formula (01), and the monomer that derives the structural unit (a03) includes the following general formula (03). The compound (03) represented by these is mentioned.

［式中、Ｒ、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４はそれぞれ前記と同じである。］

[Wherein R, R ¹ , R ² , R ³ , R ⁴ are the same as defined above. ]

The polymer compound (A1) of the present invention is a novel compound not conventionally known.
For example, when the polymer compound (A1) is blended with a positive resist composition together with the component (B), an acid is generated from the component (B) by exposure (irradiation with radiation). The bond between the carbon atom to which R ¹ , R ² and R ^{3 in} (a01) are bonded to the oxygen atom bonded to the carbon atom is broken, and the general formula “—C (R ¹ ) The group represented by (R ² ) (R ³ ) (wherein R ¹ , R ² and R ³ are the same as defined above) ”dissociates. As a result, the solubility of the polymer compound (A1) in the alkaline developer increases.
Therefore, the polymer compound (A1) is useful as a base resin for a chemically amplified positive resist composition and can be suitably used as the base component (A) of the positive resist composition of the present invention. .

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

Example 1 <Synthesis of Polymer Compound (I)>

10.45 g (66.97 mmol) of compound (1), 30.00 g (133.93 mmol) of compound (2), 4.11 g (22.32 mmol) of compound (3) was converted into 66.84 g of ethyl lactate. Dissolved. To this solution, 7.81 mmol of dimethyl azobisisobutyrate (Wako Pure Chemical Industries, Ltd .: V-601) was added as a polymerization initiator and dissolved. This reaction solution was added dropwise to 37.13 g of ethyl lactate heated to 80 ° C. in a nitrogen atmosphere over 6 hours. After completion of the dropping, the reaction solution was heated and stirred for 1 hour, and then 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. 25 g of polymer compound (I) was obtained.
About this high molecular compound (I), the mass mean molecular weight (Mw) of standard polystyrene conversion calculated | required by GPC measurement was 8900, and dispersion degree (Mw / Mn) was 1.61.
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 l1 / m1 / n1 = 30/60. / 10.

(Example 2) <Synthesis of polymer compound (II)>

10.45 g (66.97 mmol) of compound (1), 30.00 g (133.93 mmol) of compound (2), 3.84 g (22.32 mmol) of compound (4) were added to 66.44 g of ethyl lactate. Dissolved. To this solution, 7.81 mmol of dimethyl azobisisobutyrate (Wako Pure Chemical Industries, Ltd .: V-601) was added as a polymerization initiator and dissolved. This reaction solution was added dropwise to 36.90 g of ethyl lactate heated to 80 ° C. in a nitrogen atmosphere over 6 hours. After completion of the dropping, the reaction solution was heated and stirred for 1 hour, and then 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. 25 g of polymer compound (II) was obtained.
About this high molecular compound (II), the mass mean molecular weight (Mw) of standard polystyrene conversion calculated | required by GPC measurement was 8500, and dispersion degree (Mw / Mn) was 1.66.
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 l2 / m2 / n2 = 30/60. / 10.

Comparative Example 1 <Synthesis of Polymer Compound (III)>

11.38 g (66.97 mmol) of compound (5), 30.00 g (133.93 mmol) of compound (2), 5.27 g (22.32 mmol) of compound (6) were added to 69.98 g of ethyl lactate. Dissolved. To this solution, 7.81 mmol of dimethyl azobisisobutyrate (Wako Pure Chemical Industries, Ltd .: V-601) was added as a polymerization initiator and dissolved. This reaction solution was added dropwise to 38.87 g of ethyl lactate heated to 80 ° C. in a nitrogen atmosphere over 6 hours. After completion of the dropping, the reaction solution was heated and stirred for 1 hour, and then 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. 30 g of polymer compound (III) was obtained.
About this high molecular compound (III), the mass mean molecular weight (Mw) of standard polystyrene conversion calculated | required by GPC measurement was 7500, and dispersion degree (Mw / Mn) was 1.67.
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 13 / m3 / n3 = 30/60. / 10.

(Comparative Example 2) <Synthesis of Polymer Compound (IV)>

10.45 g (66.97 mmol) of compound (1), 30.00 g (133.93 mmol) of compound (2), 5.27 g (22.32 mmol) of compound (6) were added to 68.58 g of ethyl lactate. Dissolved. To this solution, 7.81 mmol of dimethyl azobisisobutyrate (Wako Pure Chemical Industries, Ltd .: V-601) was added as a polymerization initiator and dissolved. This reaction solution was added dropwise to 38.10 g of ethyl lactate heated to 80 ° C. in a nitrogen atmosphere over 6 hours. After completion of the dropping, the reaction solution was heated and stirred for 1 hour, and then 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. 30 g of polymer compound (IV) was obtained.
About this high molecular compound (IV), the mass mean molecular weight (Mw) of standard polystyrene conversion calculated | required by GPC measurement was 8000, and dispersion degree (Mw / Mn) was 1.60.
Further, 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 ¹⁴ / m4 / n4 = 30/60. / 10.

(Synthesis Example 1) <Synthesis of Compound (b)>
(I) 343.6 g of 30% aqueous sodium hydroxide solution was added dropwise to 150 g of methyl fluorosulfonyl (difluoro) acetate and 375 g of pure water while keeping the temperature at 10 ° C. or lower in an ice bath. After dropping, the mixture was refluxed at 100 ° C. for 3 hours, cooled and neutralized with concentrated hydrochloric acid. The obtained solution was added dropwise to 8888 g of acetone, and the precipitate was filtered and dried to obtain 184.5 g of compound (a) as a white solid (purity: 88.9%, yield: 95.5%). .

(Ii) 56.2 g of compound (a) and 562.2 g of acetonitrile were charged, 77.4 g of p-toluenesulfonic acid monohydrate was added, and the mixture was refluxed at 110 ° C. for 3 hours. Then, it filtered and the filtrate was concentrated and dried. To the obtained solid, 900 g of t-butyl methyl ether was added and stirred. Then, it filtered and the filtrate was dried, and 22.2 g (purity: 91.0%, yield: 44.9%) of compound (b) was obtained as a white solid.

(Synthesis Example 2) <Synthesis of Compound (f)>
(I) 4.34 g (purity: 94.1%) of the compound (b), 3.14 g of 2-benzyloxyethanol, and 43.4 g of toluene were added, and 0.47 g of p-toluenesulfonic acid monohydrate was added. And refluxed at 105 ° C. for 20 hours. The reaction solution was filtered, and 20 g of hexane was added to the filtrate and stirred. Filtration was performed again, and the residue was dried to obtain 1.41 g (yield: 43.1%) of compound (c).

(Ii) To 1.00 g of the compound (c) and 3.00 g of acetonitrile, 0.82 g of 1-adamantanecarbonyl chloride and 0.397 g of triethylamine were added dropwise under ice cooling. After completion of dropping, the mixture was stirred at room temperature for 20 hours and filtered. The filtrate was concentrated to dryness, dissolved in 30 g of dichloromethane and washed with water three times. The organic layer was concentrated and dried to obtain 0.82 g (yield: 41%) of compound (d).

(Iii) 0.384 g of the compound (e) was dissolved in 3.84 g of dichloromethane and 3.84 g of water, and 0.40 g of the compound (d) was added. After stirring for 1 hour, the organic layer was recovered by liquid separation treatment and washed with water 3.84 g three times. The obtained organic layer was concentrated and dried to obtain 0.44 g (yield: 81.5%) of compound (f).

<Preparation of resist composition>
(Example 3, Comparative Example 3)
Each component was mixed and dissolved with the composition and blending amount shown in Table 1 to prepare a positive resist composition solution.

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A) -1: the polymer compound (II).
(A) -2: the polymer compound (IV).
(A) -3: a copolymer represented by the following formula (A) -3 (mass average molecular weight (Mw) 10,000, dispersity (Mw / Mn) 1.8).
(A) -4: a copolymer represented by the following formula (A) -4 (mass average molecular weight (Mw) 7000, dispersity (Mw / Mn) 2.0).
(B) -1: Compound (f).
(D) -1: Stearyl diethanolamine.
(S) -1: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.

The copolymers represented by the formulas (A) -3 and (A) -4 were obtained by copolymerization by a known dropping polymerization method using monomers for deriving each structural unit. In formulas (A) -3 and (A) -4, the numbers attached to the lower right of () indicate the proportion (mol%) of each structural unit. This composition ratio was calculated by ¹³ C-NMR. Moreover, Mw and Mw / Mn were calculated | required on the polystyrene conversion reference | standard by a gel permeation chromatography (GPC).

<Evaluation of lithography properties>
[Resolution and sensitivity]
An organic antireflection film composition “ARC29” (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. Thus, an organic antireflection film having a film thickness of 85 nm was formed. Then, the positive resist compositions of Example 3 and Comparative Examples 3 to 5 obtained above were applied onto the antireflection film using a spinner, and conditions on a hot plate at 80 ° C. for 60 seconds were applied. The resist film having a film thickness of 120 nm was formed by performing pre-baking (PAB) treatment and drying.
Next, an ArF excimer laser (193 nm) is applied to the resist film with an ArF exposure apparatus NSR-S308F (Nikon Corp .; NA (numerical aperture) = 0.92, 2/3 annular illumination), and the target size is hole. Irradiation was selectively performed through a mask pattern (6% halftone) targeting a contact hole pattern (C / H pattern) of diameter (CD) (nm) / pitch (nm) = 85/135.
Then, a post-exposure heating (PEB) treatment is performed at 60 ° C. for 60 seconds, and a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution (product name: NMD-W, Tokyo Ohka Kogyo) at 23 ° C. (Industry Co., Ltd.) was subjected to alkali development under conditions for 30 seconds, then rinsed with pure water for 30 seconds, and then shaken off and dried.
As a result, a C / H pattern resist pattern in which holes with a hole diameter of 85 nm are arranged at equal intervals (pitch 135 nm) is formed on the resist film formed using the positive resist composition of Example 3. I was able to.
The optimum exposure dose Eop (mJ / cm ² ; sensitivity) at this time was determined to be 27.0 (mJ / cm ² ).
On the other hand, in the resist films formed using the positive resist compositions of Comparative Examples 4 to 5, the C / H pattern was not resolved. In the resist film formed using the positive resist composition of Comparative Example 3, although a C / H pattern could be formed, a part of the pattern was connected and a good pattern could not be formed.

[Roundness evaluation]
Each contact hole pattern formed above was observed from above using a scanning electron microscope (SEM), and the roundness of the hole pattern was evaluated. As a result, in Example 3, there were few unevenness | corrugations of the circumference part of the hole pattern observed from the sky, and the hole pattern was high in roundness as a whole, and was favorable shape. On the other hand, in Comparative Example 3, part of the hole pattern was connected and the roundness was low.

  From the above results, it was confirmed that the resist composition of Example 3 according to the present invention can obtain good lithography characteristics.

Claims (6)

A positive resist composition comprising a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure,
The polymer in which the substrate component (A) has a structural unit (a01) represented by the following general formula (a0-1) and a structural unit (a03) represented by the following general formula (a0-3) A positive resist composition comprising a compound (A1).

[Wherein, R is a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group, and a plurality of R may be the same or different; R ¹ is an alkyl group having 2 or more carbon atoms; R ² and R ³ are each independently an alkyl group, R ² and R ³ are bonded to each other to form a monocyclic structure having 8 or more carbon atoms; R ⁴ has a substituent. It may be a linear or monocyclic hydroxyalkyl group having 10 or less carbon atoms. ]   The positive resist composition according to claim 1, wherein the polymer compound (A1) further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.   The positive resist composition according to claim 1, further comprising a nitrogen-containing organic compound (D).   A step of forming a resist film on a support using the positive resist composition according to claim 1, a step of exposing the resist film, and an alkali developing of the resist film to form a resist A resist pattern forming method including a step of forming a pattern. A polymer compound comprising a structural unit (a01) represented by the following general formula (a0-1) and a structural unit (a03) represented by the following general formula (a0-3).

[Wherein, R is a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group, and a plurality of R may be the same or different; R ¹ is an alkyl group having 2 or more carbon atoms; R ² and R ³ are each independently an alkyl group, R ² and R ³ are bonded to each other to form a monocyclic structure having 8 or more carbon atoms; R ⁴ has a substituent. It may be a linear or monocyclic hydroxyalkyl group having 10 or less carbon atoms. ]   Furthermore, the high molecular compound of Claim 5 which has a structural unit (a2) induced | guided | derived from the acrylate ester containing a lactone containing cyclic group.