JP5608801B2 - COMPOUND, RESIST COMPOSITION AND METHOD FOR FORMING RESIST PATTERN - Google Patents

Description

  The present invention relates to a compound suitable as an acid generator for a resist composition, an acid generator comprising the compound, a resist composition containing the acid generator, and a resist pattern forming method using the 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. Currently, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has been started. Further, 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 that satisfies such requirements, a chemically amplified resist containing a base resin whose solubility in an alkaline developer is changed by the action of an acid and an acid generator that generates an acid upon exposure is used. For example, a positive chemically amplified resist contains, as a base resin, a resin whose solubility in an alkaline developer is increased by the action of an acid and an acid generator, and from the acid generator by exposure during resist pattern formation. When the acid is generated, the exposed portion becomes alkali-soluble.

Up to now, as the base resin for chemically amplified resist, polyhydroxystyrene (PHS), which is highly transparent to KrF excimer laser (248 nm), and a resin whose hydroxyl group is protected with an acid dissociable, dissolution inhibiting group (PHS resin) Has been used. However, since the PHS resin has an aromatic ring such as a benzene ring, the transparency to light having a wavelength shorter than 248 nm, for example, 193 nm, is not sufficient. For this reason, a chemically amplified resist having a PHS resin as a base resin component has drawbacks such as low resolution in a process using 193 nm light, for example.
Therefore, as a resist base resin currently used in ArF excimer laser lithography and the like, it has a structural unit generally derived from a (meth) acrylic acid ester in the main chain because it is excellent in transparency near 193 nm. Resin (acrylic resin) is used. In the case of the positive type, such a resin includes a structural unit derived from a (meth) acrylic acid ester containing a tertiary alkyl ester type acid dissociable, dissolution inhibiting group containing an aliphatic polycyclic group, for example, 2-alkyl. A resin having a structural unit derived from 2-adamantyl (meth) acrylate or the like is mainly used (for example, see Patent Document 1).

  The “(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. “(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.

  On the other hand, various acid generators used in chemically amplified resists have been proposed so far, such as onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, Diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators and the like are known. Currently, an acid generator containing a triphenylsulfonium skeleton, a dinaphthyl monophenylsulfonium skeleton, or the like is used as an acid generator (Patent Document 2).

JP 2003-241385 A Japanese Patent Laid-Open No. 2005-37888

  In recent years, miniaturization of resist patterns has been further advanced, and conventional resist compositions are required to further improve various lithographic properties in resist pattern formation. In particular, from the viewpoint of improving the process window in the lithography process, it is important to improve the exposure margin (Exposure Latitude (EL) margin) and the depth of focus (DOF). The EL margin is an exposure amount range in which a resist pattern can be formed with a dimension in which a deviation from a target dimension is within a predetermined range when exposure is performed while changing the exposure amount. The DOF is a depth of focus range in which a resist pattern can be formed with a dimension in which a deviation with respect to a target dimension is within a predetermined range when the focus is shifted up and down at the same exposure amount. The larger the area under the curve of the graph created with the EL margin as the vertical axis and the DOF as the horizontal axis, the wider the process window and the process margin. In other words, in order to widen the process window, it is required to improve both the EL margin and DOF characteristics. However, when one of these characteristics is improved, the other tends to deteriorate. difficult.

  The present invention has been made in view of the above circumstances, and is a novel composition suitable as a resist composition having improved process margin, a resist pattern forming method using the resist composition, and an acid generator for resist composition And an acid generator comprising the compound.

  A first aspect of the present invention that solves the above-described problems includes 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. A resist composition, wherein the acid generator component (B) includes an acid generator (B1) composed of a compound represented by the following general formula (b1-1): is there.

［式中、Ｒ^７”〜Ｒ^９”は、それぞれ独立に、アリール基またはアルキル基を表し；Ｒ^７”〜Ｒ^９”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^７”〜Ｒ^９”のうち少なくとも１つは、水素原子の一部または全部が、下記一般式（ｂ１４−１）で表される基、または、下記一般式（ｂ１４−２）で表される基で置換された置換アリール基であり；Ｒ^１は、置換基として酸素原子（＝Ｏ）を有する炭素数４〜２０の環状のアルキル基を表し；ｎ’は、０または１を表す。］

［式中、Ｒ^４７およびＲ^４８はそれぞれ独立して水素原子または直鎖状もしくは分岐鎖状のアルキル基であり、Ｒ^４９は炭素数１〜５のアルキル基、フッ素原子またはフッ素化アルキル基で置換されていてもよい環状のアルキル基である。ただし、Ｒ^４７およびＲ^４８のうち少なくとも１つは水素原子である。］

［式中、Ｒ^５０は直鎖状もしくは分岐鎖状のアルキレン基であり、Ｒ^５１は環状の第３級アルキルエステル型酸解離性基またはアセタール型酸解離性基である。］

[Wherein, R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group; any two of R ⁷ ″ to R ⁹ ″ are bonded to each other together with a sulfur atom in the formula A ring may be formed; at least one of R ⁷ ″ to R ⁹ ″ is a group in which part or all of the hydrogen atoms are represented by the following general formula (b14-1), or the following general formula A substituted aryl group substituted with a group represented by (b14-2); R ¹ represents a C 4-20 cyclic alkyl group having an oxygen atom (═O) as a substituent; n ′ Represents 0 or 1. ]

[Wherein, R ⁴⁷ and R ⁴⁸ each independently represent a hydrogen atom or a linear or branched alkyl group, and R ⁴⁹ represents an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. A cyclic alkyl group which may be substituted. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ]

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents a cyclic tertiary alkyl ester type acid dissociable group or acetal type acid dissociable group. ]

  Further, the second aspect of the present invention includes a step of forming a resist film on a support using the resist composition of the first aspect of the present invention, a step of exposing the resist film, and the resist film. Is a resist pattern forming method including a step of forming a resist pattern by alkali development.

  Furthermore, the third aspect of the present invention is a compound represented by the following general formula (b1-1).

［式中、Ｒ^７”〜Ｒ^９”は、それぞれ独立に、アリール基またはアルキル基を表し；Ｒ^７”〜Ｒ^９”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^７”〜Ｒ^９”のうち少なくとも１つは、水素原子の一部または全部が、下記一般式（ｂ１４−１）で表される基、または、下記一般式（ｂ１４−２）で表される基で置換された置換アリール基であり；Ｒ^１は、置換基として酸素原子（＝Ｏ）を有する炭素数４〜２０の環状のアルキル基を表し；ｎ’は、０または１を表す。］

[Wherein, R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group; any two of R ⁷ ″ to R ⁹ ″ are bonded to each other together with a sulfur atom in the formula A ring may be formed; at least one of R ⁷ ″ to R ⁹ ″ is a group in which part or all of the hydrogen atoms are represented by the following general formula (b14-1), or the following general formula A substituted aryl group substituted with a group represented by (b14-2); R ¹ represents a C 4-20 cyclic alkyl group having an oxygen atom (═O) as a substituent; n ′ Represents 0 or 1. ]

［式中、Ｒ^４７およびＲ^４８はそれぞれ独立して水素原子または直鎖状もしくは分岐鎖状のアルキル基であり、Ｒ^４９は炭素数１〜５のアルキル基、フッ素原子またはフッ素化アルキル基で置換されていてもよい環状のアルキル基である。ただし、Ｒ^４７およびＲ^４８のうち少なくとも１つは水素原子である。］

［式中、Ｒ^５０は直鎖状もしくは分岐鎖状のアルキレン基であり、Ｒ^５１は環状の第３級アルキルエステル型酸解離性基またはアセタール型酸解離性基である。］

[Wherein, R ⁴⁷ and R ⁴⁸ each independently represent a hydrogen atom or a linear or branched alkyl group, and R ⁴⁹ represents an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. A cyclic alkyl group which may be substituted. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ]

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents a cyclic tertiary alkyl ester type acid dissociable group or acetal type acid dissociable group. ]

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.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
The “lower alkyl group” means an alkyl group having 1 to 5 carbon atoms.
An “acid-dissociable group” is an organic group that can be dissociated by the action of an acid.

  According to the present invention, there are provided a novel compound suitable as an acid generator for a resist composition, an acid generator comprising the compound, a resist composition containing the acid generator, and a resist pattern forming method using the resist composition. Provided.

≪Compound≫
First, the compound represented by the above general formula (b1-1), which is the third aspect of the present invention (hereinafter, sometimes referred to as compound (b1-1)) will be described. The compound (b1-1) is suitably used as an acid generator for the resist composition which is the first aspect of the present invention.

First, the cation part of a compound (b1-1) is demonstrated.
In the general formula (b1-1), R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group. However, at least one of R ⁷ ″ to R ⁹ ″ is a substituted aryl group in which part or all of the hydrogen atoms are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group.
The aryl group for R ⁷ ″ to R ⁹ ″ 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 alkoxyalkyloxy. A substituent other than the group and the alkoxycarbonylalkyloxy group, for example, an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group and the like may or may not be substituted. Such an 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, Most preferred is a tert-butoxy group.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R ⁷ ″ to R ⁹ ″ is not particularly limited, and examples thereof include a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. 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.

At least one of R ⁷ ″ to R ⁹ ″ is a substituted aryl group in which part or all of the hydrogen atoms of the aryl group are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group. R 7 ^{"~R 9"} 2 or more of the may be the substituted aryl group, but is most preferably any one of R 7 ^{"~R 9"} is the substituted aryl group.

  Examples of the alkoxyalkyloxy group in which a hydrogen atom is substituted in the substituted aryl group include those represented by the following general formula (b14-1).

［式中、Ｒ^４７およびＲ^４８はそれぞれ独立して水素原子または直鎖状もしくは分岐鎖状のアルキル基であり、Ｒ^４９はアルキル基であり、Ｒ^４８およびＲ^４９は相互に結合して一つの環構造を形成していても良い。ただし、Ｒ^４７およびＲ^４８のうち少なくとも１つは水素原子である。］

[Wherein, R ⁴⁷ and R ⁴⁸ are each independently a hydrogen atom or a linear or branched alkyl group, R ⁴⁹ is an alkyl group, and R ⁴⁸ and R ⁴⁹ are bonded to each other. Two ring structures may be formed. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ]

In the formula, R ⁴⁷ and R ⁴⁸ are each independently a hydrogen atom or a linear or branched alkyl group, provided that at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom.
In R ⁴⁷ and R ⁴⁸ , the alkyl group preferably has 1 to 5 carbon atoms, preferably an ethyl group or a methyl group, and most preferably a methyl group.
One of R ⁴⁷ and R ⁴⁸ is preferably a hydrogen atom, the other is preferably a hydrogen atom or a methyl group, and both R ⁴⁷ and R ⁴⁸ are particularly preferably hydrogen atoms.
The alkyl group for R ⁴⁹ preferably has 1 to 15 carbon atoms and may be linear, branched or cyclic.
The linear or branched alkyl group for R ⁴⁹ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. Can be mentioned.
The cyclic alkyl group for R ⁴⁹ preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group, etc. And a group obtained by removing one or more hydrogen atoms from the polycycloalkane. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.

R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. In this case, a cyclic group is formed by R ⁴⁸ , R ⁴⁹ , the oxygen atom to which R ⁴⁹ is bonded, and the carbon atom to which the oxygen atom and R ⁴⁸ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring.

  Examples of the alkoxycarbonylalkyloxy group in which a hydrogen atom is substituted in the substituted aryl group include those represented by the following general formula (b14-2).

［式中、Ｒ^５０は直鎖状もしくは分岐鎖状のアルキレン基であり、Ｒ^５１は酸解離性基である。］

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents an acid dissociable group. ]

The linear or branched alkylene group for R ⁵⁰ preferably has 1 to 5 carbon atoms, such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, or a 1,1-dimethylethylene group. Etc.
The acid dissociable group in R ⁵¹ is not particularly limited as long as it is an organic group that can be dissociated by the action of an acid, but is a cyclic or chain tertiary alkyl ester type acid dissociable group; an acetal type such as an alkoxyalkyl group Examples include acid dissociable groups, and among these, tertiary alkyl ester type acid dissociable groups are preferable. Specifically, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 1-methyl-1-cyclopentyl group, 1-ethyl-1-cyclopentyl group, 1-methyl-1-cyclohexyl group, 1-ethyl-1-cyclohexyl group, 1- (1-adamantyl) -1-methylethyl group, 1- (1-adamantyl) -1-methylpropyl group, 1- (1-adamantyl) -1-methylbutyl group, 1- (1-adamantyl) -1-methylpentyl group; 1- (1-cyclopentyl) -1-methylethyl group, 1- (1-cyclopentyl) -1-methylpropyl group, 1- (1-cyclopentyl)- 1-methylbutyl group, 1- (1-cyclopentyl) -1-methylpentyl group; 1- (1-cyclohexyl) -1-methylethyl group, 1- (1-cyclohexyl) ) -1-methylpropyl group, 1- (1-cyclohexyl) -1-methylbutyl group, 1- (1-cyclohexyl) -1-methylpentyl group, tert-butyl group, tert-pentyl group, tert-hexyl group, etc. Is mentioned.

  In the substituted aryl group, the number of alkoxyalkyloxy groups or alkoxycarbonylalkyloxy groups substituted with hydrogen atoms is preferably 2 or less, and most preferably 1.

R ⁷ ″ to R ⁹ ″ other than the substituted aryl group are each preferably a phenyl group or a naphthyl group, and most preferably a phenyl group.

Any two of R ⁷ ″ to R ⁹ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula. In this case, it is preferable to form a 3- to 10-membered ring including a sulfur atom, and it is particularly preferable to form a 5- to 7-membered ring.

Next, the anion part of a compound (b1-1) is demonstrated.
In the general formula (b1-1), R ¹ represents a C 4-20 cyclic alkyl group having an oxygen atom (═O) as a substituent.
“Having an oxygen atom (═O) as a substituent” means that two hydrogen atoms bonded to one carbon atom constituting a cyclic alkyl group having 4 to 20 carbon atoms are replaced with an oxygen atom (═O). Means the group being
The cyclic alkyl group for R ¹ is not particularly limited as long as it has 4 to 20 carbon atoms, and may be any of a polycyclic group and a monocyclic group. For example, a monocycloalkane, a bicycloalkane, or a tricycloalkane. And groups obtained by removing one hydrogen atom from a polycycloalkane such as tetracycloalkane. As the monocyclic group, a group in which one hydrogen atom is removed from a monocycloalkane having 3 to 8 carbon atoms is preferable. Specific examples include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. it can. The polycyclic group preferably has 7 to 12 carbon atoms, and specifically includes an adamantyl group, norbornyl group, isobornyl group, tricyclodecanyl group, tetracyclododecanyl group and the like.
R ¹ is preferably a polycyclic alkyl group having 4 to 20 carbon atoms having an oxygen atom (═O) as a substituent. Industrially, 1 constitutes an adamantyl group, norbornyl group, or tetracyclododecanyl group. A group in which two hydrogen atoms bonded to carbon atoms are substituted with an oxygen atom (═O) is preferred, and a norbornyl group having an oxygen atom (═O) as a substituent is particularly preferred.

R ¹ may have a substituent other than the oxygen atom. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms.

  In the general formula (b1-1), n ′ represents 0 or 1. As the anion moiety in the compound (b1-1), n ′ is preferably 1.

The anion moiety in the compound (b1-1) in the present invention is preferably a camphorsulfonic acid ion represented by the following formula (b14-3-01) because of excellent effects of the present invention, and particularly camphorsulfone. The acid ion is preferably an ion represented by the following chemical formula (a sulfonate ion (—SO ₃ ⁻ ) bonded to a carbon atom of a methyl group bonded to the 1-position of the norbornane ring).

  Examples of the compound (b1-1) include (b1-1-1) to (b1-1-12). Preferably, they are (b1-1-1) to (b1-1-6).

<Method for producing compound>
Compound (b1-1) can be produced, for example, as follows. That is, the following general formulas (b1-14-01) and (b1-14) are contained in a solution of an organic acid H ⁺ B ⁻ (B ⁻ represents an anion part of an organic acid such as a methanesulfonate ion). −02) and the reaction is carried out, and then pure water and an organic solvent (for example, dichloromethane, tetrahydrofuran, etc.) are added to recover the organic layer. From the organic layer, the following general formula (b1- 14-03) is obtained.
Next, the compound represented by the general formula (b1-14-03) is dissolved in a mixed solvent of an organic solvent (for example, dichloromethane, tetrahydrofuran, etc.) and water, and an alkali metal salt of a desired anion X ⁻ is dissolved therein. L ⁺ X ⁻ (L ⁺ represents an alkali metal cation such as lithium ion, potassium ion, sodium ion, etc.) is added and reacted, followed by liquid separation and washing with water, and from the organic layer, the following general formula (b1 The compound represented by -14-04) is obtained.
Next, the compound represented by the general formula (b1-14-04) is dissolved in an organic solvent (for example, dichloromethane, tetrahydrofuran and the like), ice-cooled, a base (for example, sodium hydride and the like) is added, and the desired compound is added. Alkoxyalkyl group or halide of alkoxycarbonylalkyl group (for example, general formula “Cl—C (R ⁴⁷ ) (R ⁴⁸ ) —O—R ⁴⁹ ”, “Cl—R ⁵⁰ —C (═O) —O—R) ⁵¹ ”,“ Br—R ⁵⁰ —C (═O) —O—R ⁵¹ ”, etc., wherein R ^{47 to} R ⁵¹ are the same as described above), and —OH of —R ¹⁰ ″ —OH The compound (b1-1) is obtained by substituting the hydrogen atom of the group with the alkoxyalkyl group or alkoxycarbonylalkyl group.

［式中、Ｒ^８”およびＲ^９”は前記一般式（ｂ１−１）中のＲ^８”およびＲ^９”と同様であり；Ｒ^１０”は前記一般式（ｂ１−１）中のアリール基であるＲ^７”から１つの水素原子を除いたアリーレン基であり；Ｂ⁻は、有機酸のアニオン部であり；Ｌ^＋は、アルカリ金属カチオンであり；Ｒ^１およびｎ’は、前記一般式（ｂ１−１）中のＲ^１およびｎ’と同様である。］

Wherein, ^{R 8} "and ^{R 9"} is the same as ^{R 8} "and ^{R 9"} in the general formula ^{(b1-1); R 10} "is an aryl group in the general formula (b1-1) R ⁷ ″ is an arylene group obtained by removing one hydrogen atom; B ⁻ is an anion part of an organic acid; L ⁺ is an alkali metal cation; and R ¹ and n ′ are the general formulas The same as R ¹ and n ′ in (b1-1). ]

Further, the anion-exchange compound ^{(b1-14-03), L + [R} 1 - (CH 2) n'-SO 3] - prior to reacting with, ^{-R 10} of the compound (b1-14-03) The compound (b1-1) can also be obtained by replacing the hydrogen atom of the —OH group of —OH with the alkoxyalkyl group or alkoxycarbonylalkyl group and then performing anion exchange.

≪Acid generator≫
The acid generator of the fourth aspect of the present invention (hereinafter sometimes referred to as an acid generator (B1)) is composed of a compound represented by the general formula (b1-1). In the formula, R ⁷ ″ to R ⁹ ″, R ¹ and n ′ are the same as those described in the compound of the third aspect of the present invention.

≪Resist composition≫
The resist composition according to the first embodiment of the present invention comprises a base material component (A) whose solubility in an alkaline developer is changed by the action of an acid (hereinafter referred to as “component (A)”), and an acid generated upon exposure. And an acid generator component (B) (hereinafter referred to as component (B)).
When a resist film formed using such a resist composition is selectively exposed at the time of resist pattern formation, an acid is generated from the component (B), and the acid has a solubility in the alkaline developer of the component (A). Change. As a result, while the solubility of the exposed portion of the resist film in the alkaline developer changes, the unexposed portion does not change the solubility in the alkaline developer. In the case of the negative type, the unexposed part is dissolved and removed, and a resist pattern is formed.
The resist composition of the present invention may be a negative resist composition or a positive resist composition.

<(A) component>
As the component (A), organic compounds that are usually used as base material components for chemically amplified resists can be used singly or in combination of two or more.
Here, the “base material component” is an organic compound having a film forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and a nano-level resist pattern is easily formed.
The organic compound having a molecular weight of 500 or more is largely classified into a low molecular weight organic compound having a molecular weight of 500 or more and less than 2000 (hereinafter referred to as a low molecular compound) and a high molecular weight resin having a molecular weight of 2000 or more (polymer material). Separated. As the low molecular weight compound, a non-polymer is usually used. In the case of a resin (polymer, copolymer), a polystyrene-reduced mass average molecular weight by GPC (gel permeation chromatography) is used as the “molecular weight”. Hereinafter, the term “resin” refers to a resin having a molecular weight of 2000 or more.
As the component (A), a resin whose alkali solubility is changed by the action of an acid can be used, and a low molecular weight material whose alkali solubility is changed by the action of an acid can also be used.

When the resist composition of the present invention is a negative resist composition, as the component (A), a base material component that is soluble in an alkali developer is used, and a crosslinking agent is further added to the negative resist composition.
In such a negative resist composition, when an acid is generated from the component (B) by exposure, the acid acts to cause crosslinking between the base material component and the crosslinking agent, resulting in poor solubility in an alkali developer. To do. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the negative resist composition on the substrate is selectively exposed, the exposed portion turns into poorly soluble in an alkaline developer, while unexposed. Since the portion remains soluble in the alkali developer and does not change, a resist pattern can be formed by alkali development.
As the component (A) of the negative resist composition, a resin that is soluble in an alkali developer (hereinafter referred to as an alkali-soluble resin) is usually used.
As the alkali-soluble resin, a resin having a unit derived from at least one selected from α- (hydroxyalkyl) acrylic acid or a lower alkyl ester of α- (hydroxyalkyl) acrylic acid is a good resist with little swelling. A pattern can be formed, which is preferable. Α- (Hydroxyalkyl) acrylic acid includes acrylic acid in which a hydrogen atom is bonded to the α-position carbon atom to which the carboxy group is bonded, and a hydroxyalkyl group (preferably having 1 carbon atom) in the α-position carbon atom. One or both of [alpha] -hydroxyalkylacrylic acids to which (5) hydroxyalkyl groups) are attached.
As the crosslinking agent, for example, it is usually preferable to use an amino crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group because a good resist pattern with less swelling can be formed. It is preferable that the compounding quantity of a crosslinking agent is 1-50 mass parts with respect to 100 mass parts of alkali-soluble resin.

  When the resist composition of the present invention is a positive resist composition, as the component (A), a base material component whose solubility in an alkaline developer is increased by the action of an acid is used. The component (A) is hardly soluble in an alkali developer before exposure. When an acid is generated from the component (B) by exposure, the solubility in the alkali developer is increased by the action of the acid. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the positive resist composition on the substrate is selectively exposed, the exposed portion changes from poorly soluble to soluble in an alkaline developer. On the other hand, since the unexposed portion remains hardly soluble in alkali and does not change, a resist pattern can be formed by alkali development.

In the resist composition of the present invention, the component (A) is preferably a base material component whose solubility in an alkaline developer is increased by the action of an acid. That is, the resist composition of the present invention is preferably a positive resist composition.
The component (A) may be a resin component (A1) (hereinafter also referred to as component (A1)) whose solubility in an alkaline developer is increased by the action of an acid. It may be a low molecular compound (A2) (hereinafter sometimes referred to as the component (A2)) whose solubility in a liquid is increased, or a mixture thereof. Especially, it is preferable that this (A) component contains (A1) component.

[(A1) component]
As the component (A1), resin components (base resins) that are usually used as base components for chemically amplified resists can be used alone or in combination of two or more.
In this embodiment, the component (A1) preferably contains a structural unit derived from an acrylate ester.
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.
Note that the α-position (α-position carbon atom) of a structural unit derived from an acrylate ester means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
In the acrylate ester, as the lower alkyl group as a substituent at the α-position, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, Examples include lower linear or branched alkyl groups such as isopentyl group and neopentyl group.
Specific examples of the halogenated lower alkyl group include groups in which part or all of the hydrogen atoms in the above-mentioned “lower alkyl group as a substituent at the α-position” are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
In the present invention, the α-position of the acrylate ester is preferably a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and is a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group. In view of industrial availability, a hydrogen atom or a methyl group is most preferable.

In this embodiment, the component (A1) preferably contains a structural unit derived from hydroxystyrene.
Here, in the present specification and claims, the “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene.
“Hydroxystyrene” is a concept that includes hydroxystyrene and those in which the hydrogen atom at the α-position of hydroxystyrene is substituted with another substituent such as an alkyl group, and derivatives thereof. Note that the α-position (α-position carbon atom) of a structural unit derived from hydroxystyrene means a carbon atom to which a benzene ring is bonded, unless otherwise specified.
Specific examples of the alkyl group as a substituent at the α-position in hydroxystyrene include a lower alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. And a lower linear or branched alkyl group such as a group, tert-butyl group, pentyl group, isopentyl group and neopentyl group.

The component (A1) particularly preferably has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
In addition to the structural unit (a1), the component (A1) preferably further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.
The component (A1) is derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group in addition to the structural unit (a1) or in addition to the structural units (a1) and (a2). It is preferable to have a structural unit (a3).
In addition to the structural unit (a1), the component (A1) preferably further has a structural unit (a5) derived from hydroxystyrene.

・ Structural unit (a1)
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and dissociates with an acid. This increases the solubility of the entire component in an alkaline developer, and those that have been proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. .

Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.
Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.

“Aliphatic branched” means having a branched structure having no aromaticity.
The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
As the aliphatic branched acid dissociable, dissolution inhibiting group, a tertiary alkyl group having 4 to 8 carbon atoms is preferable, and specific examples include a tert-butyl group, a tert-pentyl group, and a tert-heptyl group. .

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a lower alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O) and the like.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include monocycloalkanes, bicycloalkanes, tricycloalkanes, tetracycloalkanes which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group. And groups obtained by removing one or more hydrogen atoms from a polycycloalkane. More specifically, 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 are exemplified. .

  Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include a group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group. Specifically, 2-methyl-2 -Adamantyl group, 2-ethyl-2-adamantyl group, etc. are mentioned. Alternatively, in the structural units represented by the following general formulas (a1 ″ -1) to (a1 ″ -6), an adamantyl group such as a group bonded to an oxygen atom of a carbonyloxy group (—C (O) —O—) An aliphatic cyclic group such as a cyclohexyl group, a cyclopentyl group, a norbornyl group, a tricyclodecanyl group, or a tetracyclododecanyl group, and a branched alkylene group having a tertiary carbon atom bonded thereto. Groups.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｒ^１５、Ｒ^１６はアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５である）を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹⁵ and R ^{16 each} represents an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms. Is). ]

  In the general formulas (a1 ″ -1) to (a1 ″ -6), the lower alkyl group or halogenated lower alkyl group of R is a lower alkyl group or halogenated lower alkyl which may be bonded to the α-position of the acrylate ester. It is the same as the alkyl group.

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

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または低級アルキル基を表し、ｎは０〜３の整数を表し、Ｙは低級アルキル基または脂肪族環式基を表す。］

[Wherein, R ¹ ′ and R ² ′ each independently represents a hydrogen atom or a lower alkyl group, n represents an integer of 0 to 3, and Y represents a lower alkyl group or an aliphatic cyclic group. ]

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

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

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

Examples of the lower alkyl group for Y include the same lower alkyl groups as those described above for R.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups that have been proposed in a number of conventional ArF resists. For example, the above “aliphatic ring” Examples thereof are the same as those in the formula group.

  Examples of the acetal type acid dissociable, dissolution inhibiting group also include a group represented by the following general formula (p2).

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状もしくは分岐鎖状のアルキル基または水素原子であり、Ｒ^１９は直鎖状、分岐鎖状または環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状または分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

[Wherein, R ¹⁷ and R ¹⁸ each independently represent a linear or branched alkyl group or a hydrogen atom, and R ¹⁹ represents a linear, branched or cyclic alkyl group. Alternatively, R ¹⁷ and R ¹⁹ may be each independently a linear or branched alkylene group, and the end of R ^{17 and} the end of R ¹⁹ may be bonded to form a ring. ]

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group.
In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ 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. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula, R ¹⁷ and R ¹⁹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon atoms), and the end of R ^{19 and} the end of R ¹⁷ And may be combined.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  As the structural unit (a1), structural units represented by general formula (a1-0-1) shown below, structural units represented by general formula (a1-0-2) shown below, and general formulas (a1-0- shown below) It is preferable to use one or more selected from the group consisting of the structural units represented by 3).

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

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

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

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

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^３は酸解離性溶解抑制基を示し；Ｙ^３は脂肪族環式基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X ³ represents an acid dissociable, dissolution inhibiting group; Y ³ represents an aliphatic cyclic group. ]

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

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).

Examples of the divalent linking group for Y ² include an alkylene group, a divalent aliphatic cyclic group, and a divalent linking group containing a hetero atom.
As the aliphatic cyclic group, those similar to the explanation of the “aliphatic cyclic group” can be used except that a group in which two or more hydrogen atoms are removed is used.
When Y ² is an alkylene group, it is preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Most preferably it is.
When Y ² is a divalent aliphatic cyclic group, a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane, or tetracyclododecane is particularly preferable. .
When Y ² is a divalent linking group containing a hetero atom, examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group or an acyl group), —S—. , —S (═O) ₂ —, —S (═O) ₂ —O—, “—Y ^a —O (oxygen atom) —Y ^b — (Y ^a and Y ^b are each independently a substituent. And a divalent hydrocarbon group which may have a hydrogen atom).

When Y ² is —NH—, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. It is particularly preferred that
When Y ² is “Y ^a —O—Y ^b ”, Y ^a and Y ^b are each independently a divalent hydrocarbon group which may have a substituent.
The hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.

The hydrocarbon group for Y ^a may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.

The aliphatic hydrocarbon group for Y ^a may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group for Y ^a include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group having a ring in the structure.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 2 to 5, and most preferably 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group, an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [— (CH ₂ ) ₃ -], tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as - _{CH (CH 3) CH 2 -} , - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 Alkylethylene groups such as CH ₃ ) CH ₂ —; alkyltrimethylene groups such as —CH (CH ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) CH ₂ —; —CH (CH ₃ ) CH _{2 CH 2 CH 2 -, - CH} 2 CH (CH 3) CH 2 CH 2 - , etc. And alkyl alkylene groups such as Le Kill tetramethylene group. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (═O), and the like.

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

As Y ^a , a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 2 to 5 carbon atoms is further preferable, and an ethylene group is most preferable.

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

In general formula (a1-0-3), R is the same as defined above.
X ³ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group, acetal type acid dissociable, dissolution inhibiting group, and the like. And an acetal type acid dissociable, dissolution inhibiting group is preferred, and specific examples include a group represented by the above formula (p1) and a group represented by the above formula (p2).
As the aliphatic cyclic group for Y ^3, the same as described above for the “aliphatic cyclic group” can be used except that a group in which two or more hydrogen atoms are removed is used.

  More specifically, examples of the structural unit (a1) include structural units represented by general formulas (a1-1) to (a1-5) shown below.

［式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５の低級アルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表し；Ｙ^２は２価の連結基を表し；Ｒは前記と同じであり、Ｒ^１’、Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５の低級アルキル基を表す。Ｙ^３は脂肪族環式基を示し、Ｒ^１７〜Ｒ^１９は前記と同じである。］

[Wherein, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a lower alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; n represents an integer of 0 to 3] Y ² represents a divalent linking group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. Y ³ represents an aliphatic cyclic group, and R ^{17 to} R ¹⁹ are the same as described above. ]

In the formula, X 'can be mentioned the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1) ', R 2'} , n, Y The same thing is mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).
The Y ^3, the same groups as those described above for ^{Y 3} in the general formula above (a1-0-3).
R ¹⁷ to R ¹⁹ include the same as ^R 17 ^{to R 19} in the general formula (p2) above.

Specific examples of the structural units represented by the general formulas (a1-1) to (a1-5) are shown below. In the following formulae, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among these, the structural unit represented by general formula (a1-1), (a1-3) or (a1-5) is preferable, and specifically, (a1-1-1) to (a1-1-4). , (A1-1-20) to (a1-1-23), (a1-1-32), (a1-3-25) to (a1-3-28) and (a1-5-1) to ( It is more preferable to use at least one selected from the group consisting of a1-5-5).
Furthermore, as the structural unit (a1), those represented by the following general formula (a1-1-01) that include structural units of the formula (a1-1-1) to the formula (a1-1-3), The following general formula including the structural units of formulas (a1-1-16) to (a1-1-17) and formulas (a1-1-20) to (a1-1-23) and (a1-1-32) What is represented by (a1-1-02), which is represented by the following general formula (a1-3-01) including the structural units of formulas (a1-3-25) to (a1-3-26) Or those represented by the following general formula (a1-3-02) including the structural units of formulas (a1-3-27) to (a1-3-28) are also preferable.

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

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹¹ represents a lower alkyl group. ]

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１２は低級アルキル基を示す。ｈは１〜６の整数を表す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹² represents a lower alkyl group. h represents an integer of 1 to 6. ]

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

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

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｒ^１４は低級アルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数であり、ｎ’は１〜６の整数である。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹⁴ represents a lower alkyl group, R ¹³ represents a hydrogen atom or a methyl group, and a represents an integer of 1 to 10. , N ′ is an integer of 1-6. ]

In general formula (a1-1-01), R is the same as defined above.
The lower alkyl group for R ^{11 is the same as} the lower alkyl group for R, and is preferably a methyl group or an ethyl group.
In general formula (a1-1-02), R is the same as defined above.
The lower alkyl group for R ^{12 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group. h is preferably 1 to 4, and most preferably 4.

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

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a1) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, more preferably 25 to 60 mol%, based on all structural units constituting the component (A1). Is more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.
When the structural unit represented by the general formula (a1-5) is contained in the component (A1), the proportion of the structural unit represented by the general formula (a1-5) is the total amount constituting the component (A1). 1-20 mol% is preferable with respect to a structural unit, 2-15 mol% is more preferable, and 3-12 mol% is further more preferable. Lithographic properties such as resolution can be improved by setting the value to the lower limit value or more, and balance with other structural units can be obtained by setting the upper limit value or less.

・ 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, and when it is only the lactone ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
The lactone cyclic group of the structural unit (a2) has an affinity for a developer containing water or a high-molecular compound (A1) when the polymer film (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 (a1).
Examples of the lower alkyl group for R ′ include the same as the lower alkyl group for R in the structural unit (a1).
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom or Groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorinated 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. Is mentioned.
In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Specific examples of the alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or sulfur atom of A ″ include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, —O—CH ₂ —. _{, -CH 2 -O-CH 2 -} , - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
Below, the specific structural unit of the said general formula (a2-1)-(a2-5) is illustrated. In the following formula, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

  As the structural unit (a2), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formulas (a2-1) to ( At least one selected from the group consisting of structural units represented by a2-3) is more preferred. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-7), (a2-3-1), and (a2-3-) It is preferable to use at least one selected from the group consisting of structural units represented by 5).

As the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a2) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, based on the total of all the structural units constituting the component (A1). 50 mol% is more preferable. By making it the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by making it the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a3)
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A1) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which part of hydrogen atoms of an alkyl group is substituted with a fluorine atom, and a hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a polycyclic aliphatic hydrocarbon group (polycyclic group). It is done. As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. The polycyclic group preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

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

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

[Wherein, R is 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.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, and more preferably 5 to 25 mol% with respect to all the structural units constituting the component (A1). Is more preferable. By setting it to the lower limit value or more, the effect of containing the structural unit (a3) can be sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a4)
The component (A1) may contain other structural units (a4) other than the structural units (a1) to (a3) as long as the effects of the present invention are not impaired.
The structural unit (a4) is not particularly limited as long as it is another structural unit that is not classified into the structural units (a1) to (a3) described above, and is for ArF excimer laser and KrF excimer laser (preferably ArF excimer). A number of hitherto known materials can be used for resist resins such as lasers.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing 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.

  Further, as other structural units other than the structural units (a1) to (a3), for example, a structural unit derived from hydroxystyrene (hereinafter referred to as “structural unit (a5)”), a structural unit derived from styrene. (Hereinafter referred to as “structural unit (a6)”) and the like are also preferable.

・ Structural unit (a5)
The structural unit (a5) is a structural unit derived from hydroxystyrene.
When the component (A1) has the structural unit (a5), in addition to the effects of the present invention, dry etching resistance is improved. Furthermore, the structural unit (a5) also has the advantage that the raw material hydroxystyrene is readily available and is inexpensive.
Specific examples of the structural unit (a5) include those having the following general formulas (a5-1) to (a5-2).

［式中、Ｒ^４は水素原子又は炭素数１〜５の低級アルキル基であり、Ｒ^５はハロゲン原子、炭素数１〜５の低級アルキル基又はハロゲン化アルキル基であり；ｐ’は１〜３の整数であり、ｑは０〜４の整数である。ただし、ｐ’＋ｑは１以上５以下である。式（ａ５−２）中、Ｘ^３は酸解離性溶解抑制基を示す。］

[Wherein R ⁴ is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, R ⁵ is a halogen atom, a lower alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group; Is an integer of 3, q is an integer of 0-4. However, p ′ + q is 1 or more and 5 or less. In formula (a5-2), X ³ represents an acid dissociable, dissolution inhibiting group. ]

In the formulas (a5-1) to (a5-2), R ⁴ is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms.
Examples of the lower alkyl group for R ⁴ include the same lower alkyl groups that may be bonded to the α-position of the hydroxystyrene.

In formulas (a5-1) to (a5-2), R ⁵ represents a halogen atom, a lower alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group.
Examples of the halogen atom for R ⁵ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
Examples of the lower alkyl group for R ⁵ include the same lower alkyl groups that may be bonded to the α-position of the hydroxystyrene.
Halogenated alkyl group for R ^5, part or all of the hydrogen atoms of the lower alkyl groups described above R ⁵ is exemplified been substituted with a halogen atom, it is preferably a fluorinated lower alkyl group.

In the formulas (a5-1) to (a5-2), p ′ is an integer of 1 to 3, and preferably 1.
The bonding position of the hydroxyl group may be any of the o-position, m-position and p-position of the phenyl group. When p ′ is 1, the p-position is preferred because it is readily available and inexpensive. When p ′ is 2 or 3, any substitution position can be combined.

In the formulas (a5-1) to (a5-2), q is an integer of 0 to 4, preferably an integer of 0 to 2, preferably 0 or 1, particularly industrially 0. It is preferable that
When q is 1, the substitution position of R ⁵ may be any of the o-position, the m-position, and the p-position. When q is 2, arbitrary substitution positions can be combined. The plurality of R ⁵ may be the same or different.
However, p ′ + q is 1 or more and 5 or less.

In formula (a5-2), X ³ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the same as X ³ in general formula (a1-0-3) described above. It is done.
X ³ is preferably an acetal type acid dissociable, dissolution inhibiting group, particularly preferably a group represented by the above formula (p1) or a group represented by the formula (p2).

  In the component (A1), as the structural unit (a5), one type of structural unit may be used alone, or two or more types may be used in combination.

  The proportion of the structural unit (a5) in the component (A1) is 45 to 90 moles relative to the total of all structural units constituting the component (A1) in the structure of the general formula (a5-1). %, More preferably 50 to 85 mol%, still more preferably 55 to 80 mol%. By setting it to be equal to or higher than the lower limit of the above range, moderate alkali solubility can be obtained. Moreover, the effect by containing a structural unit (a5) is fully acquired. By setting it to be equal to or less than the upper limit value of the range, it is possible to balance with other structural units.

  Moreover, in the thing of the structure of general formula (a5-2), it is preferable that it is 5-70 mol% with respect to the sum total of all the structural units which comprise the said (A1) component, and 5-65 mol% is more. Preferably, 5 to 60 mol% is more preferable, and 5 to 55 mol% is most preferable. By setting it to the lower limit value or more of the range, a good resist pattern can be obtained when the resist composition is used, and by setting the upper limit value or less, the balance with other structural units is good.

・ Structural unit (a6)
The structural unit (a6) is a structural unit derived from styrene.
In the present invention, the structural unit (a6) is not essential, but when it is contained, the solubility in an alkali developer can be adjusted. Moreover, since dry etching tolerance improves, it is preferable.
In this specification, “styrene” is a concept including styrene and those in which the α-position hydrogen atom of styrene is substituted with another substituent such as an alkyl group.
“Structural unit derived from styrene” means a structural unit formed by cleavage of an ethylenic double bond of styrene. In styrene, the hydrogen atom of the phenyl group may be substituted with a substituent such as an alkyl group having 1 to 5 carbon atoms.
Specific examples of the structural unit (a6) include those having the following general formula (a6-1).

［式（ａ６−１）中、Ｒ^４は前記と同じであり；Ｒ^７はハロゲン原子、炭素数１〜５の低級アルキル基又はハロゲン化アルキル基であり；ｒは０〜３の整数である。］

[In formula (a6-1), R ⁴ is as defined above; R ⁷ is a halogen atom, a lower alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group; and r is an integer of 0 to 3. . ]

In the general formula (a6-1), R ⁴ is the same as R ⁴ in the above formula (a5-1).
R ⁷ is the same as R ⁵ in the above formula (a5-1).
r is an integer of 0 to 3, preferably 0 or 1, and industrially particularly preferably 0.
When r is 1, the substitution position of R ⁷ may be any of the o-position, m-position and p-position of the phenyl group. When r is 2 or 3, arbitrary substitution positions can be combined. The plurality of R ⁷ may be the same or different.

As the structural unit (a6), one type may be used alone, or two or more types may be used in combination.
When the component (A1) has the structural unit (a6), the proportion of the structural unit (a6) in the component (A1) is 1 to 20 mol% with respect to the total of all the structural units constituting the component (A1). Preferably, 3-15 mol% is more preferable, and 5-15 mol% is further more preferable. The effect by having a structural unit (a6) as it is more than the lower limit of the said range is high, and the balance with another structural unit is favorable as it is below the upper limit of the said range.

  In the present invention, the component (A1) preferably contains a copolymer having the structural units (a1), (a2) and (a3). Examples of the copolymer include copolymers composed of the structural units (a1), (a2) and (a3), copolymers composed of the structural units (a1), (a2), (a3) and (a4). Can be mentioned. Moreover, as this copolymer, 1 type may be used independently and 2 or more types may be used together.

  Specifically, examples of the component (A1) include copolymers having the following structural units.

［式中、Ｒは前記と同じである。複数のＲはそれぞれ同じでも異なっていてもよい。］

[Wherein, R is the same as defined above. A plurality of R may be the same or different. ]

In the present invention, the component (A1) preferably contains a copolymer having the structural units (a1), (a3) and (a5).
Examples of the copolymer include the structural unit represented by the formula (a5-1), the structural unit represented by the formula (a3-1), and the structural unit represented by the formula (a5-2). And a copolymer composed of a structural unit represented by the formula (a1-5).

  Specifically, examples of the component (A1) include copolymers having the following structural units.

［式中、Ｒは前記と同じである。複数のＲはそれぞれ同じでも異なっていてもよい。Ｒ^１７〜Ｒ^１９は前記と同じである。複数のＲ^１７〜Ｒ^１９はそれぞれ同じでも異なっていてもよい。］

[Wherein, R is the same as defined above. A plurality of R may be the same or different. R ^{17 to} R ¹⁹ are the same as described above. The plurality of R ^{17 to} R ¹⁹ may be the same or different. ]

The component (A1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN).
Further, for the component (A1), in the polymerization, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that the terminal A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing
Further, the component (A1) suppresses acid dissociable dissolution of a hydrogen atom of a hydroxy group in a structural unit derived from hydroxystyrene or a hydrogen atom of a hydroxy group in the structural unit (a3) containing a hydroxy group as a polar group. It can also be obtained by carrying out a reaction for substitution with an organic group containing a group or an acid dissociable, dissolution inhibiting group.

The mass average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the component (A1) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 5000 to 20000. Most preferred. If it is smaller than the upper limit of this range, there is sufficient solubility in a resist solvent to be used as a resist, and if 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.

[(A2) component]
As the component (A2), a low molecular compound having a molecular weight of 500 or more and less than 2000 and having an acid dissociable, dissolution inhibiting group and a hydrophilic group as exemplified in the description of the component (A1) above is preferable. Specifically, a compound in which a part of hydrogen atoms of a hydroxyl group of a compound having a plurality of phenol skeletons is substituted with the acid dissociable, dissolution inhibiting group can be mentioned.
The component (A2) is, for example, a part of the hydrogen atom of the hydroxyl group of a low molecular weight phenol compound known as a sensitizer in a non-chemically amplified g-line or i-line resist or a heat resistance improver. Those substituted with a soluble dissolution inhibiting group are preferred and can be arbitrarily used.
Examples of such low molecular weight phenol compounds include bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl). ) Propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-trihydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-) 3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3, 4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyph Phenylmethane, bis (4-hydroxy-3-methylphenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl- 4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, Examples include 2, 3, 4 nuclei of formalin condensates of phenols such as phenol, m-cresol, p-cresol or xylenol. Of course, it is not limited to these.
The acid dissociable, dissolution inhibiting group is not particularly limited, and examples thereof include those described above.

As the component (A), one type may be used alone, or two or more types may be used in combination.
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) includes an acid generator composed of the compound (B1) represented by the general formula (b1-1) (hereinafter sometimes referred to as the component (B1)). The component (B1) is the same as the compound (B1) of the present invention.
(B1) A component can be used 1 type or in mixture of 2 or more types.
In the resist composition of the present invention, the component (B1) can be used alone as the component (B). When used by mixing with an acid generator other than the component (B1), the content of the component (B1) in the component (B) is preferably 10% by mass or more, and is 10 to 60% by mass. More preferably, the content is 15 to 50% by mass. By being at least the lower limit of the range, when a resist pattern is formed using the resist composition, lithography characteristics such as pattern shape, exposure (EL) margin, depth of focus (DOF), etc. are improved.
In particular, when a resist pattern is formed using a resist composition for immersion exposure or a resist composition for forming an upper resist film, the lithography characteristics are improved. When forming a three-layer resist laminate, it is preferable because matching with the lower layer film of the resist is good, and resist pattern tailing and the like can be suppressed.

  Moreover, in the resist composition of this invention, it is preferable that content of (B1) component is 0.5-60 mass parts with respect to 100 mass parts of said (A) component, and is 1-40 mass parts. More preferably, it is 1-30 parts by mass, most preferably 1-10 parts by mass. By being at least the lower limit of the range, lithography characteristics are improved particularly when a resist pattern is formed in a resist composition for immersion exposure or a resist composition for forming an upper resist film. On the other hand, storage stability will become favorable by being below an upper limit.

In the component (B), an acid generator (B2) other than the component (B1) (hereinafter referred to as the component (B2)) may be used in combination with the component (B1).
The component (B2) is not particularly limited as long as it is other than the component (B1), 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, Most preferred is a tert-butoxy group.
The alkoxy group that may be substituted for the hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may be substituted for 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 those described above for R ¹ ″ to R ³ ″.

Preferable examples of the cation moiety of the compound represented by the formula (b-1) include cation moieties represented by the following formulas (I-1-1) to (I-1-10). Among these, those having a triphenylsulfonium skeleton such as a cation moiety represented by formulas (I-1-1) to (I-1-8) are preferable.
In the following formulas (I-1-9) to (I-1-10), R ⁹ and R ¹⁰ are each independently a phenyl group, naphthyl group or carbon number 1 to 5 which may have a substituent. An alkyl group, an alkoxy group, and a hydroxyl group.
u is an integer of 1 to 3, and 1 or 2 is most preferable.

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 a halogen atom, a hetero atom, an alkyl group, and a formula: XQ ^1- [wherein 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, oxygen 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 —, —C (═O) —O—R. ⁹³ —O—C (═O) — (wherein R ^{91 to} R ⁹³ are each independently an alkylene group).
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. Among them, —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) — O—, —C (═O) —O—R ⁹³ — 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, more preferably 5 to 20, still more 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, such as 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, heicosyl 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 are removed from a monocycloalkane; a group in which one or more hydrogen atoms are 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 one or more hydrogen atoms from the polycycloalkane are substituted. 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.

In the present invention, ^{R 4} ", ^{X-Q 1} - as a substituent preferably has the case, ^{R 4."} The, ^{X-Q 1} -Y 1 - in the Formula, ^{Q 1} and X are the Y ¹ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. ] Is preferable.
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.
Moreover, the onium salt which replaced the anion part of these onium salts with alkyl sulfonates, such as methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, can also be used.
Moreover, the onium salt which replaced the anion part of these onium salts by the anion part represented by either of following formula (b1)-(b8) can also be used.

［式中、ｐは１〜３の整数であり、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｇは１〜２０の整数であり、ｔ３は１〜３の整数であり、Ｒ^７は置換基である。ｖ０は０〜３の整数である。］

[Wherein, p is an integer of 1 to 3, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, and r1 to r2 are each independently 0 to 3] It is an integer, g is an integer of 1 to 20, t3 is an integer of 1 to 3, and R ⁷ is a substituent. v0 is an integer of 0-3. ]

［式中、ｐ、Ｒ^７、Ｑ”はそれぞれ前記と同じであり、ｎ１〜ｎ５はそれぞれ独立に０または１であり、ｖ１〜ｖ５はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ５はそれぞれ独立に０〜３の整数である。］

[Wherein, p, R ⁷ and Q ″ are the same as defined above, n1 to n5 are each independently 0 or 1, v1 to v5 are each independently an integer of 0 to 3, w1 to w5 Are each independently an integer of 0 to 3.]

Examples of the substituent for R ⁷ are the same as those described above as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in X. Can be mentioned.
Code (r1 and r2, w1 to w5) attached to R ⁷ when is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.
r1 to r2 and w1 to w5 are each preferably an integer of 0 to 2, and more preferably 0 or 1.
t3 is preferably 1 or 2, and most preferably 1.
q3 is preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

  Moreover, as an onium salt type | system | group acid generator, in the said general formula (b-1) or (b-2), an anion part is represented by the following general formula (b-3) or (b-4). An onium salt-based acid generator replaced with 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 for R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 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 Nthenyl 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 18] to [Chemical 19]), pamphlet of International Publication No. 04/074242, An oxime sulfonate-based acid generator disclosed in Examples 1 to 40) on pages 65 to 85 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.

  As the component (B2), one type of acid generator may be used alone, or two or more types may be used in combination.

  Content of (B) component in the resist composition of this invention is 0.5-60 mass parts with respect to 100 mass parts of (A) component, Preferably it is 1-40 mass parts. 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.

<(D) component>
The resist composition of the present invention can contain a nitrogen-containing organic compound (D) (hereinafter referred to as “component (D)”) as an optional component.
The component (D) is not particularly limited as long as it acts as an acid diffusion control agent, that is, a quencher that traps the acid generated from the component (B) by exposure, and a wide variety of components have already been proposed. Therefore, it may be used arbitrarily from known ones, and among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred. An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include amines (alkyl amines or alkyl alcohol amines) in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms. Specific examples thereof include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di-n-heptylamine, Dialkylamines such as di-n-octylamine and dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-heptyl Trialkylamines such as amine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n -Ok Noruamin, alkyl alcohol amines such as tri -n- octanol amine.
Among these, alkyl alcohol amines and trialkyl amines are preferable, and alkyl alcohol amines are most preferable. Of the alkyl alcohol amines, triethanolamine and triisopropanolamine are most preferred.
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. By setting the content in the above range, the resist pattern shape, the stability over time, and the like are improved.

<Optional component>
[(E) component]
The resist composition of the present invention comprises, as optional components, an organic carboxylic acid, a phosphorus oxo acid, and derivatives thereof for the purpose of preventing sensitivity deterioration and improving the resist pattern shape, retention stability over time, and the like. 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.

[(S) component]
The resist composition of the present invention can be produced by dissolving the material in an organic solvent (S) (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, and 2-heptanone; many such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol Monohydric alcohols; compounds having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl of the polyhydric alcohols or compound having the ester bond Ether alkyl such as ether, monopropyl ether, monobutyl ether or monophenyl ether Derivatives of polyhydric alcohols such as compounds having a propylene glycol monomethyl ether acetate (PGMEA) or propylene glycol monomethyl ether (PGME) among these]; cyclic ethers such as dioxane, methyl lactate, Esters such as ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, Aromatic organics such as dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene A solvent etc. can be mentioned.
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. In general, the solid content concentration of the resist composition is 2 -20% by mass, preferably 5-15% by mass.

The resist composition of the present invention is a novel one that has not been conventionally known.
Further, since the compound (b1-1) of the present invention is contained as an acid generator, it is excellent in both EL margin and DOF characteristics and has a large process window. Therefore, by using the resist composition, the process margin when forming a resist pattern is improved. Further, by using the resist composition, film loss is suppressed, and a highly rectangular resist pattern with high rectangularity can be formed.
As described above, the EL margin is a range of exposure amount that can form a resist pattern with a dimension within which a deviation from the target dimension is within a predetermined range when the exposure amount is changed, that is, a mask pattern. This is the range of exposure amount that can provide a faithful resist pattern. The larger the value, the smaller the change in pattern size that accompanies fluctuations in the exposure amount, and the process margin is improved.

The reason for such an effect is not clear, but is presumed as follows.
The component (B1) has a structure in which a hydroxyl group bonded to an aryl group is protected by a tertiary alkyl ester type or an acetal type acid dissociable group such as an alkoxyalkyl group as a cation part, In the non-exposed part, the structure does not change. Therefore, it is considered that the compound represented by the general formula (b1-1) exhibits a dissolution inhibiting effect on the alkali developer with respect to the component (A1) in the non-exposed portion of the resist film.
On the other hand, in the exposed area, during the post-exposure heating (PEB) with the generated acid, the acid dissociable group is dissociated from the oxygen atom constituting the hydroxyl group, resulting in a compound in which the hydroxyl group is bonded to the aryl group, It is considered that the component (A1) exhibits an effect of promoting dissolution in an alkali developer.
Therefore, it is considered that the contrast of the exposed / non-exposed area can be increased.

  In addition, the component (B1) has a specific anion portion containing a cyclic group as the anion portion, so that the amount of acid after exposure is excessive as compared with the anion portion of a conventional acid generator such as nonafluorobutanesulfonate. Diffusion is suppressed. As a result, the EL margin is large, the process margin is improved, and a resist pattern with good lithography characteristics can be formed.

  As described above, by combining an anion portion having a specific structure with a cation portion having the same structure, both an EL margin and a DOF can be improved. It is speculated that a compound suitable for the above can be obtained. And by including (B1) component which consists of this compound, the resist composition of this invention has a larger process margin at the time of resist pattern formation than the conventional resist composition which does not contain (B1) component. It is considered to have excellent lithography properties.

  The resist composition of the present invention is more soluble in the organic solvent (S) component used to dissolve various components of the resist than the conventional resist composition not containing the component (B1). Is excellent. This is presumably because the affinity with an organic solvent was sufficiently increased by introducing an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group as a substituent into the aryl group in the cation part of the component (B1). The Thus, it is speculated that the fact that the uniformity of the distribution in the resist film is improved due to the excellent solubility in the organic solvent (S) component also contributes to the improvement of the lithography characteristics.

  Furthermore, the resist composition of the present invention can be suitably used as a resist composition for immersion exposure in a resist pattern forming method including an immersion exposure step, and good lithography characteristics can be obtained. Moreover, in the resist pattern formation method including the process of forming a 3 layer resist laminated body, it can be used suitably as a positive resist composition for upper layer resist film formation, and a favorable lithography characteristic is acquired. This is because the (B1) component is used as the (B) component, so that the resist composition of the present invention has an immersion exposure medium such as water as compared with the conventional resist composition not containing the (B1) component. This is presumed to be due to the small amount of substance elution.

  In the resist composition of the present invention, when the (B1) component is used in combination with an acid generator that is a stronger acid than the (B1) component, the (B1) component effectively acts as a quencher. It is considered that a good resist pattern can be formed.

≪Resist pattern formation method≫
Next, the resist pattern forming method of the second aspect of the present invention will be described.
The resist pattern forming method of the present invention includes a step of forming a resist film using the resist composition according to the first aspect of the present invention, a step of exposing the resist film, and an alkali development of the resist film to form a resist pattern It is a method including the process of forming.

The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the resist composition according to the first aspect of the present invention is applied onto a support with a spinner or the like, and prebaked (post-apply bake (PAB)) at 40 to 120 ° C. under a temperature condition of 80 to 150 ° C. Second, preferably 60 to 90 seconds, and selectively exposed to ArF excimer laser light through a desired mask pattern using, for example, an ArF exposure apparatus, and then heated after exposure under a temperature condition of 80 to 150 ° C. (Post exposure bake (PEB) treatment) is performed for 40 to 120 seconds, preferably 60 to 90 seconds. Subsequently, this is developed with an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide, 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 substrate 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. It is also effective for immersion exposure.

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, at the time of exposure, a solvent (having a refractive index larger than the refractive index of air) is formed between a lens and a resist film on the wafer, which is conventionally filled with an inert gas such as air or nitrogen. Exposure is performed in a state filled with the immersion medium.
More specifically, the immersion exposure is 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, exposure can be performed 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.).

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
In the following examples, the compound represented by the chemical formula (II) is referred to as “compound (II)”, and the compounds represented by other chemical formulas are also described in the same manner.

[Synthesis Example 1]
Compound (II) 4.34 g (purity: 94.1%), 2-benzyloxyethanol 3.14 g, toluene 43.4 g were charged, p-toluenesulfonic acid monohydrate 0.47 g was added, and 105 ° C. At reflux 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 (III).

^{1 H-NMR (DMSO-d6,400MHz} ): δ (ppm) = 4.74-4.83 (t, 1H, OH), 4.18-4.22 (t, 2H, H a), 3. 59-3.64 (q, 2H, ^Hb ).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 106.6.
From the results described above, it was confirmed that the compound (III) had a structure shown below.

[Synthesis Example 2]
To 1.00 g of compound (III) 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 (IV).

The obtained compound (IV) was analyzed by NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 8.81 (s, 1H, H ^c ), 4.37-4.44 (t, 2H, H ^d ), 4.17-4 .26 (t, 2H, H ^e ), 3.03-3.15 (q, 6H, H ^b ), 1.61-1.98 (m, 15H, Adamantane), 1.10-1.24 ( t, 9H, H ^a ).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 106.61.
From the results described above, it was confirmed that the compound (IV) had a structure shown below.

[Synthesis Example 3: Synthesis of Compound (B2-1)]
0.384 g of compound (V) was dissolved in 3.84 g of dichloromethane and 3.84 g of pure water, and 0.40 g of compound (IV) 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 (B2-1).

The obtained compound (B2-1) was analyzed by NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 7.57-7.87 (m, 14H, Phenyl), 4.40-4.42 (t, 2H, H ^b ), 4. 15-4.22 (t, 2H, H ^a ), 2.43 (s, 3H, H ^c ), 1.60-1.93 (m, 15H, Adamantane).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 106.7.
From the results shown above, it was confirmed that the compound (B2-1) had a structure shown below.

[Synthesis Example 4: Synthesis of Compound (B2-3)]
To 60.75 g of methanesulfonic acid controlled at 20 ° C. or less, 8.53 g of phosphorus oxide, 8.81 g of 2,5-dimethylphenol and 12.2 g of diphenyl sulfoxide were added little by little. After aging for 30 minutes while controlling the temperature at 15 to 20 ° C., the temperature was raised to 40 ° C. and aging was performed for 2 hours. Thereafter, the reaction solution was dropped into 109.35 g of pure water cooled to 15 ° C. or lower. After completion of the dropwise addition, 54.68 g of dichloromethane was added, and after stirring, the dichloromethane layer was recovered. A separate container was charged with 386.86 g of hexane at 20 to 25 ° C., and the dichloromethane layer was added dropwise. After completion of the dropwise addition, the mixture was aged at 20 to 25 ° C. for 30 minutes and then filtered to obtain 17.14 g (yield: 70.9%) of the target compound (VI).
The obtained compound (VI) was analyzed by NMR.
¹ H-NMR (DMSO-d6, 600 MHz): δ (ppm) = 7.61-7.72 (m, 10H, phenyl), 7.14 (s, 2H, H ^c ), 3.12 (s, 3H, H ^b ), 2.22 (s, 6H, H ^a ).
From the results shown above, it was confirmed that the compound (VI) had a structure shown below.

4 g of compound (VI) was dissolved in 79.8 g of dichloromethane. After confirming dissolution, 6.87 g of potassium carbonate was added, and 3.42 g of methyl adamantane bromoacetate was added. After reaction for 24 hours under reflux, filtration, washing with water were performed, and crystallization was performed with hexane. The obtained powder was dried under reduced pressure to obtain 3.98 g (yield 66%) of the target compound (VII).
The obtained compound (VII) was analyzed by NMR.
¹ H-NMR (CDCl ₃ , 400 MHz): δ (ppm) = 7.83-7.86 (m, 4H, Phenyl), 7.69-7.78 (m, 6H, Phenyl), 7.51 ( s, 2H, H ^d ), 4.46 (s, 2H, H ^c ), 2.39 (s, 6H, H ^a ), 2.33 (s, 2H, Adamantan), 2.17 (s, 2H) , Adamantan), 1.71-1.98 (m, 11H, Adamantan), 1.68 (s, 3H, H ^b ), 1.57-1.61 (m, 2H, Adamantan).
From the results shown above, it was confirmed that the compound (VII) had a structure shown below.

  4.77 g of compound (VII) was dissolved in 23.83 g of dichloromethane and 23.83 g of pure water, and 3.22 g of compound (IV) 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 4.98 g (yield 87%) of compound (B2-3).

The obtained compound (B2-3) was analyzed by NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 7.76-7.88 (m, 10H, Phenyl), 7.62 (s, 2H, Phenyl), 4.64 (s, 2H) , H ^b ), 4.43-4.44 (t, 2H, H ^e ), 4.22-4.23 (t, 2H, H ^d ), 1.51-2.36 (m, 38H, Adamantan + H ^a + ^Hc ).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 106.7.
From the results above, it was confirmed that the compound (B2-3) had a structure shown below.

<Synthesis of acid generator (B1)>
In this example, the compound (B1-1) used as the acid generator (B1) was synthesized according to the synthesis examples shown below.

[Example 1: Synthesis example of compound (B1-1)]
Compound (X) [wherein X ⁻ is a mixture of Br ⁻ and Cl ⁻ {Br ⁻ / Cl ⁻ = 84/16 (wt%)}] is mixed with 20.00 g of dichloromethane and 10.00 g of pure water. After dissolving in a solvent, 6.176 g of compound (XI) was added and stirred at room temperature for 5 hours. Thereafter, the organic layer was recovered by liquid separation treatment and washed with water. The obtained organic layer was concentrated and dried to obtain 9.17 g of compound (B1-1).

The obtained compound (B1-1) was analyzed by NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 0.07 (s, 3H, CH ₃ ), 1.02 (s, 3H, CH ₃ ), 1.23-1.25 (d , 2H, camphor), 1.49-1.96 ( m, 18H, Adamantan + camphor), 2.18-2.36 (m, 10H, Adamantan + camphor), 2.32 (s, 6H, CH 3), 2. 67-2.71 (t, 1H, camphor) , 2.82-2.86 (d, 1H, camphor), 4.61 (s, 2H, CH 2), 7.60-7.86 (m, 12H, Ar)
From the results above, it was confirmed that the compound (B1-1) had a structure shown above.

<Evaluation of solubility of acid generator in organic solvent>
(Example 2, Comparative Examples 1-2)
Using the above compound (B1-1), the following compound (B2-2), and a compound (b′-01) (di (1-naphthyl) phenylsulfonium nonafluorobutanesulfonate) widely used as an acid generator, The solubility of the acid generator in the following organic solvents was evaluated by the following evaluation methods.
(Organic solvent)
PGMEA: Propylene glycol monomethyl ether acetate.
PGME: Propylene glycol monomethyl ether.
EL: ethyl lactate.

[Evaluation method]
A predetermined amount of the organic solvent was added to each powder of the compound used as the acid generator and mixed, and the concentration (mass%) at which the solution was dissolved at room temperature (23 ° C.) was evaluated.
The obtained evaluation results are shown in Table 1. The solubility of the compound (B1-1) according to the present invention in PGME, PGMEA, and EL, which are general resist solvents, is a compound (b′-01) widely used as an acid generator, It was confirmed that the compound was superior to the following compound (B2-2).

<Preparation of resist composition (1)>
(Examples 3-4, Reference Examples 1-2)
Each component shown in Table 2 was mixed and dissolved to prepare a positive resist composition.

In Table 2, each abbreviation indicates the following, and the numerical value in [] is the blending amount (part by mass).
(A) -1: a copolymer represented by the following chemical formula (A1-11-1), Mw10000, Mw / Mn = 1.5. In the formula, the variable at the lower right of () is a1 / a2 / a3 = 40/40/20, and indicates the ratio (mol%) of each structural unit.

  (A) -2: a copolymer represented by the following chemical formula (A1-11-2), Mw7000, Mw / Mn = 1.5. In the formula, the variable at the lower right of () is a1 / a2 / a3 = 35/45/20, and indicates the ratio (mol%) of each structural unit.

(B) -1: Compound (B2-1) represented by the following chemical formula (B2-1).
(B) -2: Compound (B2-2) represented by the following chemical formula (B2-2).
(B) -3: Compound (B2-3) represented by the following chemical formula (B2-3).
(B) -4: Compound (B1-1) represented by the following chemical formula (B1-1).

(D) -1: tri-n-pentylamine.
(E) -1: salicylic acid.
(S) -1: γ-butyrolactone.
(S) -2: Mixed solvent of PGMEA / PGME = 6/4 (mass ratio).

<Evaluation of lithography characteristics (1)>
Using the obtained resist composition, a resist pattern was formed by the following procedure, and the lithography characteristics were evaluated.

[Resist pattern formation]
An organic antireflection film composition “ARC95” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto a 12-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a thickness of 90 nm was formed. Each of the positive resist compositions prepared above is applied onto the antireflection film using a spinner, prebaked (PAB) on a hot plate at 110 ° C. for 60 seconds, and dried. Thus, a resist film having a thickness of 100 nm was formed.
Next, a protective film forming coating solution “TILC-057” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the resist film using a spinner and heated at 90 ° C. for 60 seconds. A top coat having a thickness of 35 nm was formed.
Next, an ArF immersion exposure apparatus NSR-S609B (manufactured by Nikon Corporation; NA (numerical aperture) = 1.07, σ Di-pole 35 (0.78 / 0.97)) is used as a top through the mask pattern. The resist film on which the coat was formed was selectively irradiated with an ArF excimer laser (193 nm).
Thereafter, PEB treatment was performed at 100 ° C. for 60 seconds, and further developed with a 2.38 mass% TMAH aqueous solution NMD-3 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. for 10 seconds, and then pure water was added for 15 seconds. The sample was rinsed with water and dried by shaking.
As a result, in each example, a line and space pattern (hereinafter referred to as “LS pattern”) having a line width of 50 nm and a pitch of 100 nm was formed on the resist film.
The sensitivity at the time of forming the 50 nm LS pattern was determined as the optimum exposure dose Eop (mJ / cm ² ). Table 3 shows the Eop of each positive resist composition.

[sensitivity]
In the above resist pattern formation, the optimum exposure dose Eop (mJ / cm ² ; sensitivity) for forming an LS pattern having a line width of 50 nm and a pitch of 100 nm was determined. The results are shown in Table 3.

[EL margin evaluation]
The exposure amount when the line of the LS pattern is formed within the range of ± 5% (47.5 nm to 52.5 nm) of the target dimension (line width 50 nm) is obtained, and the EL margin (unit:%) is calculated by the following formula. Asked. The results are shown in Table 3.
EL margin (%) = (| E1-E2 | / Eop) × 100
E1 represents an exposure amount (mJ / cm ² ) when an LS pattern having a line width of 47.5 nm is formed, and E2 represents an exposure amount (mJ / cm ² ) when an LS pattern having a line width of 52.5 nm is formed. cm ² ).

[Evaluation of depth of focus (DOF)]
In the above Eop, the focal point was appropriately shifted up and down, and the depth of focus (DOF, unit: μm) was determined within the range in which the LS pattern was resolved and the pattern could be formed. The results are shown in Table 3.

[Measurement of elution amount]
The positive resist composition prepared above was applied onto an 8-inch silicon wafer using a spinner, pre-baked (PAB) at 110 ° C. for 60 seconds on a hot plate, and dried to obtain a film thickness. A 100 nm resist film was formed.
Next, using VRC310S (trade name, manufactured by S.E.S. Co., Ltd.), 1 drop (150 μl) of pure water is moved at room temperature to draw a circle from the center of the wafer at a constant linear velocity. (The total contact area of the resist film in contact with the droplet was 221.56 cm ² ).
Thereafter, the droplets are collected and analyzed by an analyzer Agilent-HP1100 LC-MSD (trade name, manufactured by Agilent Technologies), and the total elution amount of the component (B) before exposure, The elution amount of the cation part and the anion part (× 10 ⁻¹² mol / cm ² · s) was determined. About the anion part of (B) component, the elution amount was calculated | required separately for camphorsulfonic acid (CS) and other than that. The results are shown in Table 3.

  As is apparent from the results in Table 3, Examples 3 to 4 according to the present invention have a larger EL margin and a smaller change in the resist pattern dimension when the exposure amount fluctuates than Reference Examples 1 and 2. I was able to confirm. Furthermore, it was confirmed that Examples 3 to 4 according to the present invention had the same or higher DOF value than Reference Examples 1 and 2, and good lithography characteristics. That is, from these results, by including the compound (B1-1) of the present invention as an acid generator, a resist composition that is excellent in both EL margin and DOF and improved in process margin can be obtained. Is clear.

  Moreover, from the result of Table 3, Examples 3-4 have few elution amounts of the anion part of (B) component in the immersion medium (water) before and behind exposure processing compared with Reference Examples 1-2. It was. Further, in Example 3, the amount of elution of the cation part of the component (B) in the immersion medium (water) before and after the exposure processing is smaller than that in Reference Example 1, and Example 4 is a reference. Compared with Example 2, the elution amount of the cation part of the component (B) in the immersion medium (water) before and after the exposure processing was reduced. Therefore, it was confirmed that Examples 3 to 4 have a high substance elution suppressing effect during immersion exposure. That is, from these results, it is clear that the resist composition of the present invention has a good lithographic property even when used for immersion exposure because the substance elution into the immersion medium (water) is small. It is.

<Preparation of resist composition (2)>
(Examples 5 to 8, Comparative Example 3)
Each component shown in Table 4 was mixed and dissolved to prepare a positive resist composition.

In Table 4, each abbreviation indicates the following, and the numerical value in [] is the blending amount (part by mass).
(A) -3: a copolymer represented by the following chemical formula (A1-11-3), Mw9200, Mw / Mn = 1.5. In the formula, the variable at the lower right of () is a51 / a3 / a52 / a15 = 57/23/14/6, and indicates the ratio (mol%) of each structural unit.

(B) -2: Compound (B2-2) represented by the chemical formula (B2-2).
(B) -4: Compound (B1-1) represented by the chemical formula (B1-1).
(D) -2: Trioctylamine.
(E) -1: salicylic acid.
(S) -3: PGMEA / PGME = 3/7 (mass ratio) mixed solvent.

<Evaluation of lithography characteristics (2)>
Using the obtained resist composition, a resist pattern was formed by the following procedure, and the lithography characteristics were evaluated.

[Resist pattern formation]
The positive resist composition obtained in the above preparation (2) was coated on an 8-inch silicon substrate that had been subjected to hexamethyldisilazane (HMDS) treatment at 90 ° C. for 30 seconds. ”, Manufactured by Tokyo Electron Co., Ltd.), pre-baked (PAB) at 100 ° C. for 90 seconds, and dried to form a resist film having a thickness of 200 nm.
Next, drawing (exposure) was performed on the resist film at an acceleration voltage of 70 keV using an electron beam drawing machine HL-800D (VSB) (manufactured by Hitachi).
Thereafter, a baking (PEB) treatment was performed at 110 ° C. for 90 seconds, and a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) at 23 ° C. (trade name: NMD-3, Tokyo Ohka Kogyo Co., Ltd.) For 60 seconds, and then rinsed with pure water for 15 seconds.
As a result, in each example, a line and space pattern (LS pattern) having a line width of 100 nm and a pitch of 200 nm was formed.

[sensitivity]
In the above resist pattern formation, the optimum exposure dose Eop (mJ / cm ² ; sensitivity) for forming an LS pattern with a line width of 100 nm and a pitch of 200 nm was determined. The results are shown in Table 5.

[Evaluation of film thickness and cross-sectional shape of resist pattern]
The height change in the cross section of the obtained LS pattern and the cross-sectional shape thereof were observed using a scanning electron microscope (trade name: S-9220, manufactured by Hitachi, Ltd.).
For film reduction, the amount of change in height decreased from the initial film thickness (200 nm) was observed and indicated as “film reduction (nm)”. The film reduction is more preferable as the value of “film reduction (nm)” is smaller. The results are shown in Table 5.
The cross-sectional shape of the resist pattern was evaluated based on the following criteria. The results are shown in Table 5.
○: The top portion was not rounded, and the side wall of the line was perpendicular to the substrate surface at the interface with the substrate, and the rectangularity was high.
(Triangle | delta): There was no roundness of the top part, but it was a little undercut shape.
X: The top part was round.

[EL margin evaluation]
The exposure amount when the line of the LS pattern was formed within the range of ± 10% (90 nm to 110 nm) of the target dimension (line width 100 nm) was determined, and the EL margin was determined by the same formula as above. The results are shown in Table 5.

  As is clear from the results in Table 5, Examples 5 to 8 according to the present invention have a smaller “film reduction (nm)” value and a higher cross-sectional shape than those of Comparative Example 3. It was confirmed that a resist pattern having a good shape could be formed. Furthermore, it was confirmed that Examples 5 to 8 according to the present invention had a larger EL margin and a smaller change in the resist pattern dimension when the exposure amount changed compared to Comparative Example 3.

Claims (7)

A resist composition 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,
The resist composition, wherein the acid generator component (B) includes an acid generator (B1) composed of a compound represented by the following general formula (b1-1).

[Wherein, R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group; any two of R ⁷ ″ to R ⁹ ″ are bonded to each other together with a sulfur atom in the formula A ring may be formed; at least one of R ⁷ ″ to R ⁹ ″ is a group in which part or all of the hydrogen atoms are represented by the following general formula (b14-1), or the following general formula A substituted aryl group substituted with a group represented by (b14-2); R ¹ represents a C 4-20 cyclic alkyl group having an oxygen atom (═O) as a substituent; n ′ Represents 0 or 1. ]

[Wherein, R ⁴⁷ and R ⁴⁸ each independently represent a hydrogen atom or a linear or branched alkyl group, and R ⁴⁹ represents an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. A cyclic alkyl group which may be substituted. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ]

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents a cyclic tertiary alkyl ester type acid dissociable group or acetal type acid dissociable group. ]   The base component (A) contains a resin component (A1) whose solubility in an alkaline developer is increased by the action of an acid, and the resin component (A1) has a substituent bonded to the α-position carbon atom. The resist composition according to claim 1, which has a structural unit (a1) which is a structural unit derived from an acrylate ester which may be contained and contains an acid dissociable, dissolution inhibiting group.   The resin component (A1) further includes a structural unit (a2) that is a structural unit derived from an acrylate ester in which a substituent may be bonded to the carbon atom at the α-position and includes a lactone-containing cyclic group. The resist composition according to claim 2.   The resin component (A1) is further a structural unit derived from an acrylate ester in which a substituent may be bonded to a carbon atom at the α-position and containing a polar group-containing aliphatic hydrocarbon group ( The resist composition according to claim 2 or 3, which has a3).   The resist composition as described in any one of Claims 1-4 containing a nitrogen-containing organic compound (D).   A step of forming a resist film on the support using the resist composition according to any one of claims 1 to 5, a step of exposing the resist film, and an alkali developing of the resist film to form a resist pattern A resist pattern forming method including a step of forming a film. The compound represented by the following general formula (b1-1).

[Wherein, R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group; any two of R ⁷ ″ to R ⁹ ″ are bonded to each other together with a sulfur atom in the formula A ring may be formed; at least one of R ⁷ ″ to R ⁹ ″ is a group in which part or all of the hydrogen atoms are represented by the following general formula (b14-1), or the following general formula A substituted aryl group substituted with a group represented by (b14-2); R ¹ represents a C 4-20 cyclic alkyl group having an oxygen atom (═O) as a substituent; n ′ Represents 0 or 1. ]

[Wherein, R ⁴⁷ and R ⁴⁸ each independently represent a hydrogen atom or a linear or branched alkyl group, and R ⁴⁹ represents an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. A cyclic alkyl group which may be substituted. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ]

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents a cyclic tertiary alkyl ester type acid dissociable group or acetal type acid dissociable group. ]