JP2009019003A - Positive-type resist composition for liquid immersion lithography and resist pattern-forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new compound, to provide a positive-type resist composition using the compound, and having hydrophobicity suitable for liquid immersion lithography, and to provide a resist pattern-forming method. <P>SOLUTION: The compound is represented by general formula (F1) [wherein, X is a group for inhibiting acid-dissociable dissolution, and having a fluorine atom; and n is an integer of 1-4; R<SP>50</SP>is an n-valent organic group which may have a substituent; with the proviso that when n is 1, R<SP>50</SP>is an organic group free from a polymerizable group]. The positive-type resist composition for the liquid immersion lithography contains (A) a base material component the solubility of which in an alkali developing solution is increased by the action of an acid, (B) an acid-generating agent component generating the acid by the exposure, and (F) the compound represented by general formula (F1). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a positive resist composition for liquid immersion exposure and a method for forming a resist pattern, which are used for liquid immersion lithography.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to radiation such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film.
Along with the miniaturization of semiconductor elements, the wavelength of an exposure light source has been shortened and the projection lens has a high numerical aperture (high NA). Currently, an exposure of NA = 0.84 using an ArF excimer laser having a wavelength of 193 nm as a light source. A machine has been developed. Along with the shortening of the wavelength of the exposure light source, the resist material is required to be improved in lithography characteristics such as sensitivity to the exposure light source and resolution capable of reproducing a pattern with a fine dimension. As a resist material that satisfies such requirements, a chemically amplified resist containing a base resin whose solubility in an alkaline developer is changed by the action of an acid and an acid generator that generates an acid upon exposure is used.
Currently, as a base resin of a chemically amplified resist used in ArF excimer laser lithography and the like, a resin having a structural unit derived from (meth) acrylic acid ester in the main chain because of its excellent transparency near 193 nm ( Acrylic resin) is generally used.
Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.

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

In recent years, with respect to fluorine-containing compounds, attention has been paid to characteristics such as water repellency and transparency, and research and development in various fields has been actively conducted. For example, in the field of resist materials, acid instabilities such as methoxymethyl group, tert-butyl group, and tert-butyloxycarbonyl group are added to fluorine-containing polymer compounds for use as the base resin of positive chemically amplified resists. Introducing groups. However, when such a fluorine-based polymer compound is used as a base resin of a positive resist composition, there are disadvantages such as generation of a large amount of outgas after exposure and insufficient resistance to dry etching gas (etching resistance). is there.
Recently, a fluorine-containing polymer compound having an acid labile group containing a cyclic hydrocarbon group has been reported as a fluorine-containing polymer compound having excellent etching resistance (see, for example, Non-Patent Document 2).
Proceedings of SPIE, 5754, 119-128 (2005). Proceedings of SPIE, 4690, 76-83 (2002).

In immersion exposure, in addition to normal lithography characteristics (sensitivity, resolution, etching resistance, etc.), a resist material having characteristics corresponding to the immersion exposure technique is required. As a specific example, when the immersion medium is water and the immersion exposure is performed using a scanning immersion exposure machine as described in Non-Patent Document 1, the immersion medium is a lens. Water tracking is required to follow the movement of the water. If the water followability is low, the exposure speed is lowered, and there is a concern that the productivity may be affected. This water followability is thought to be improved by increasing the hydrophobicity of the resist film (hydrophobizing). On the other hand, even if the resist film is simply hydrophobized, there is an adverse effect on the lithography properties, for example, resolution. There is a tendency for the sensitivity to decrease and the amount of scum to increase. Further, when the hydrophobicity of the resist film is not high, the substance may be eluted from the resist film into the immersion solvent to contaminate the lens of the exposure apparatus, which may adversely affect the lithography characteristics. Therefore, further protection measures against this are required.
Thus, in immersion exposure, the development of materials with appropriate hydrophobicity is an important issue. However, there are currently few known materials that satisfy both lithography characteristics and characteristics required for immersion exposure.
The present invention has been made in view of the above circumstances, and provides a novel compound, a positive resist composition having hydrophobicity suitable for immersion exposure using the compound, and a resist pattern forming method. This is the issue.

The present inventors propose the following means in order to solve the above problems.
That is, the first aspect of the present invention is a compound represented by the following general formula (F1).

［式（Ｆ１）中、Ｘはフッ素原子を有する酸解離性溶解抑制基を示し；ｎは１〜４の整数を表す。Ｒ^５０はｎ価の有機基であって、置換基を有していてもよい。ただし、ｎが１の場合、Ｒ^５０は重合性基を含まない有機基である。］

[In formula (F1), X represents an acid dissociable, dissolution inhibiting group having a fluorine atom; n represents an integer of 1 to 4. R ⁵⁰ is an n-valent organic group and may have a substituent. However, when n is 1, R ⁵⁰ is an organic group containing no polymerizable group. ]

  The second aspect of the present invention includes a base material component (A) whose solubility in an alkaline developer is increased by the action of an acid, an acid generator component (B) that generates an acid upon exposure, and the general formula A positive resist composition for immersion exposure, comprising the compound (F) represented by (F1).

  The third aspect of the present invention includes a step of forming a resist film on a support using the positive resist composition for immersion exposure according to the second aspect, a step of immersing the resist film, and The resist pattern forming method includes a step of forming a resist pattern by alkali developing the resist film.

In the present specification and claims, an “organic group” is a group containing a carbon atom, and an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom (a fluorine atom, A chlorine atom, etc.).
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
“Lower alkyl group” refers to an alkyl group having 1 to 5 carbon atoms.
“Structural unit” means a monomer unit (monomer unit) constituting a resin (polymer, polymer compound).
“Exposure” is a concept including general irradiation of radiation.

  INDUSTRIAL APPLICABILITY According to the present invention, a novel compound, a positive resist composition having hydrophobicity suitable for immersion exposure using the compound, and a resist pattern forming method can be provided.

≪Compound≫
The compound of the present invention (hereinafter referred to as compound (F)) is represented by the general formula (F1).
In formula (F1), X represents an acid dissociable, dissolution inhibiting group having a fluorine atom.
X in the compound (F) has an alkali dissolution inhibiting property that makes the compound (F) hardly soluble in an alkali developer before dissociation, and is dissociated by the action of an acid to cause an alkali developer of the compound (F). So far, it can be appropriately selected from those proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists.
In X, the preferred acid dissociable, dissolution inhibiting group not substituted with a fluorine atom is a group that forms a chain or cyclic tertiary alkyl ester with the carboxy group in compound (F), an alkoxyalkyl. And acetal type acid dissociable, dissolution inhibiting groups such as groups, tertiary alkyloxycarbonyl groups, and alkoxycarbonylalkyl groups.

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.

Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.
“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 10 carbon atoms is preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the compound (F) 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 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. .
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- A 2-adamantyl group, a 2-ethyl-2-adamantyl group, and the like can be given. Alternatively, an aliphatic cyclic group such as an adamantyl group, a cyclohexyl group, a cyclopentyl group, a norbornyl group, a tricyclodecanyl group, or a tetracyclododecanyl group, and a branched chain alkylene having a tertiary carbon atom bonded thereto And a group having a 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, this 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.
Specific examples of the lower alkyl group for R ¹ ′ and R ² ′ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. And a linear or branched alkyl group such as 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 as those exemplified as the lower alkyl group for R ¹ ′ and R ² ′.
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とＲ^１９とが相互に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 R ¹⁷ and R ¹⁹ may be bonded to each other 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. And the like, in which a hydrogen atom is removed. Specific examples thereof include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Of these, a group in which one or more hydrogen atoms have been removed from adamantane is preferred.
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 R ¹⁹ and R ¹⁷ are You may couple | bond together. 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 4-7 membered ring, and more preferably a 4-6 membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

 The tertiary alkyl group in the “tertiary alkyloxycarbonyl group” is preferably a tertiary alkyl group having 4 to 8 carbon atoms, specifically, a tert-butyl group, a tert-pentyl group, or a tert-heptyl group. Etc. Specific examples of the tertiary alkyloxycarbonyl group include a tert-butyloxycarbonyl group and a tert-pentyloxycarbonyl group.

As the “alkoxycarbonylalkyl group”, a group represented by — (CH ₂ ) _{n ″} —C (═O) —O—R ²⁰ is preferable. R ²⁰ represents a linear, branched or cyclic alkyl group. And a group similar to R ^{19. The} n ″ is an integer of 1 to 3, and is preferably 1.

 Among the above, in X, the acid dissociable, dissolution inhibiting group that is not substituted with a fluorine atom is more preferably a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, and an aliphatic branched acid Particularly preferred is a dissociable, dissolution inhibiting group.

 In the compound (F), X is an acid dissociable, dissolution inhibiting group having a fluorine atom, and a part or all of the hydrogen atoms in the acid dissociable, dissolution inhibiting group are substituted with a fluorine atom. The fluorination rate of the acid dissociable, dissolution inhibiting group (the ratio of fluorine atoms in the acid dissociable, dissolution inhibiting group) is preferably 1 to 50%, more preferably 5 to 40, and more preferably 10 to 30. % Is most preferred.

  Among the above, X is particularly preferably a group represented by the following general formula (F1-1-1) because of excellent effects of the present invention.

［式（Ｆ１−１−１）中、Ｒ^１〜Ｒ^３はそれぞれ独立してアルキル基またはフッ素化アルキル基であって、前記フッ素化アルキル基はＲ^１〜Ｒ^３が結合している第三級炭素原子に隣接する炭素原子にはフッ素原子が結合していない基であり、かつ、Ｒ^１〜Ｒ^３の少なくとも一つは前記フッ素化アルキル基である。ただし、Ｒ^２およびＲ^３は相互に結合して、Ｒ^２とＲ^３と前記第三級炭素原子とからなる一つの環構造を形成していてもよい。］

[In Formula (F1-1-1), R ^{1 to} R ³ are each independently an alkyl group or a fluorinated alkyl group, and the fluorinated alkyl group is a ^third bonded to R ^{1 to} R ³ . The carbon atom adjacent to the secondary carbon atom is a group in which no fluorine atom is bonded, and at least one of R ^{1 to} R ³ is the fluorinated alkyl group. However, R ² and R ³ may be bonded to each other to form one ring structure composed of R ² , R ³ and the tertiary carbon atom. ]

In the formula (F1-1-1), R ^{1 to} R ³ are each independently an “alkyl group” or a fluorinated alkyl group.
Here, the “alkyl group” may be linear, branched or cyclic.
In the case of a linear or branched chain, the alkyl group preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When it is cyclic, the alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. For example, groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane can be exemplified. Specific examples thereof include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.

The fluorinated alkyl group is a group in which part or all of the hydrogen atoms in the alkyl group excluding the methyl group are substituted with fluorine atoms. However, it is a group in which no fluorine atom is bonded to the carbon atom adjacent to the tertiary carbon atom to which R ^{1 to} R ³ are bonded. Here, the alkyl group not substituted with a fluorine atom may be linear, branched or cyclic.
In the case of a linear or branched chain, the alkyl group not substituted with a fluorine atom preferably has 2 to 7 carbon atoms, more preferably 2 to 5 carbon atoms, and n- A butyl group is particularly preferred.
In the case of a ring, examples of the alkyl group not substituted with a fluorine atom include the same alkyl groups as those described above for the “alkyl group”.
The carbon atom to which the fluorine atom in the fluorinated alkyl group is bonded is preferably separated from the tertiary carbon atom to which R ^{1 to} R ³ are bonded.
Preferable examples of such fluorinated alkyl groups include 4,4,4-trifluoro-n-butyl group.
In formula (F1-1-1), at least one of R ^{1 to} R ³ is the fluorinated alkyl group. Among these, it is preferable that any one of R ^{1 to} R ³ is the fluorinated alkyl group, and the remaining two are alkyl groups.

However, in formula (F1-1-1), R ² and R ³ may be bonded to each other to form one ring structure composed of R ² , R ³ and the tertiary carbon atom. . In such a case, R ² and R ³ are preferably not fluorinated, and in this case, R ¹ is the fluorinated alkyl group. Examples of the cyclic alkyl group formed by R ² , R ³ and the tertiary carbon atom at this time are the same as those described above for the “alkyl group”.

  In said Formula (F1), n represents the integer of 1-4, it is preferable that it is 1-3, and since it is excellent in the effect of this invention, it is especially preferable that it is 1 or 2.

In Formula (F1), R ⁵⁰ is an n-valent organic group, and may have a substituent.
As the organic group for R ⁵⁰ , when it is a monovalent organic group, for example, a substituted or unsubstituted alkyl group is preferably exemplified.
Here, the substituted alkyl group means that part or all of the hydrogen atoms of the unsubstituted alkyl group are substituted with a substituent.
The unsubstituted alkyl group may be a linear, branched or cyclic alkyl group, or a combination of a linear or branched alkyl group and a cyclic alkyl group. Also good.
The linear or branched alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10, still more preferably 1 to 8, and particularly preferably 1 to 6. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group.
Examples of the cyclic alkyl group include groups in which one hydrogen atom has been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Specific examples include monocycloalkyl groups such as cyclopentyl group and cyclohexyl group, and polycycloalkyl groups such as adamantyl group, norbornyl group, isobornyl group, tricyclodecanyl group, and tetracyclododecanyl group.
A combination of a linear or branched alkyl group and a cyclic alkyl group includes a group in which a cyclic alkyl group is bonded as a substituent to a linear or branched alkyl group, and a substituent to the cyclic alkyl group. And a group in which a linear or branched alkyl group is bonded.

Moreover, as an organic group of R ⁵⁰ , when n is 1, for example, a substituted or unsubstituted aromatic group is also exemplified.
Here, the substituted aromatic group means that part or all of the hydrogen atoms of the unsubstituted aromatic group are substituted with a substituent.
As the unsubstituted aromatic group, an aryl group is preferable. As the aryl group, those having 6 to 20 carbon atoms are preferable, and examples thereof include a phenyl group and a naphthyl group.

In the organic group represented by R ⁵⁰ , examples of the substituent that the alkyl group or aromatic group may have include an unsaturated aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a substituent containing a hetero atom. It is done.
Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity.
Examples of the unsaturated aliphatic hydrocarbon group include an alkenyl group. Examples of the alkenyl group include those having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and a vinyl group and a propenyl group are preferable.
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, biphenyl group, fluorenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, and phenanthryl group. An alkylaryl group in which an alkyl group is bonded as a substituent to the aryl group; an arylalkyl group in which an aryl group is bonded as a substituent to the alkyl group; Examples of the alkylaryl group or the alkyl group in the arylalkyl group include those similar to the unsubstituted alkyl group.

The heteroatom in the “substituent containing a heteroatom” is an atom other than a carbon atom and a hydrogen atom. For example, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom (a fluorine atom, a chlorine atom, an iodine atom, a bromine atom, etc. ) And the like.
Examples of the substituent containing a hetero atom include an oxygen atom (═O), a halogen atom, a halogenated alkyl group, a hydroxyl group, a carboxy group, an amino group, a cyano group, a heterocyclic group, and a general formula R ²¹ —A′—. [Wherein R ²¹ represents a hydrocarbon group, and A ′ represents a linking group containing a hetero atom. ] Etc. which are represented by these.
Examples of the heterocyclic group include heteroaliphatic cyclic groups such as a tetrahydropyranyl group and a tetrahydrofuranyl group, and heteroaromatic cyclic groups such as a furfuryl group, a thiophenyl group, and a pyridyl group.

In the general formula R ²¹ -A'- group represented by a hydrocarbon group R ²¹ may be either an aliphatic hydrocarbon group may be an aromatic hydrocarbon group. Examples of the aliphatic hydrocarbon group include an alkyl group and an unsaturated aliphatic hydrocarbon group. Examples of the alkyl group include those similar to the unsubstituted alkyl group. Examples of the unsaturated aliphatic hydrocarbon group include the same ones as those exemplified as the substituent that the alkyl group may have.
Examples of the linking group containing a heteroatom of A ′ include a group containing a heteroatom exemplified in the substituent containing the heteroatom. For example, —O—, —C (═O) —, —C (═O ) —O—, —NH—, —NR ²² (R ²² is an alkyl group) —, —NH—C (═O) —, ═N— and the like.
Specific examples of the group represented by the general formula R ²¹ —A′— include an alkoxy group, a (meth) acryloyl group, an alkylcarbonyl group, and an alkylcarbonyloxy group.

In addition, when R ⁵⁰ is a divalent to tetravalent organic group (n is 2 to 4), the organic group of R ⁵⁰ includes 2 to 4 hydrogen atoms of the organic group exemplified in the case where n is 1. Preferred examples thereof include:

However, when n is 1, R ⁵⁰ is an organic group containing no polymerizable group. Specifically, ethylenic double bonds such as vinyl group (CH ₂ ═CH—), allyl group (CH ₂ ═CHCH ₂ —), propenyl group (CH ₃ CH═CH—), (meth) acryloyl group, such double bonds cycloolefin indicates that it is not included in R ^50.

Among the above, R ⁵⁰ is preferably a saturated hydrocarbon group or an aromatic group, and more preferably a saturated hydrocarbon group, because the effect of the present invention is excellent.
When R ⁵⁰ is a monovalent organic group (n is 1), an alkyl group is preferred, an unsubstituted alkyl group is more preferred, a linear, branched or cyclic alkyl group is particularly preferred, and a hexyl group or Most preferred is an adamantyl group.
When R ⁵⁰ is a divalent organic group (n is 2), an alkylene group is preferred, an unsubstituted alkylene group is more preferred, a linear, branched or cyclic alkylene group is particularly preferred, and a hexylene group Or the group which remove | excluded two hydrogen atoms from adamantane is the most preferable.

In ^{R 50 - (C (= O} ) -O-X) n - as the coupling location, for example, in the case of n = ^{1, R 50} is a straight-chain alkyl group, the terminal carbon of the alkyl group It is preferably an atom. When n = 2, it is preferable that R ⁵⁰ is a linear alkylene group and is a carbon atom at both terminals of the alkylene group.
For example, when n = 1 and R ⁵⁰ is an adamantyl group, it is preferably bonded to the 1-position of the adamantyl group. When n = 2 and R ⁵⁰ is a group obtained by removing two hydrogen atoms from adamantane, it is preferably bonded to the 1- and 3-positions of the adamantyl group. When n = 3 and R ⁵⁰ is a group obtained by removing three hydrogen atoms from adamantane, it is preferably bonded to the 1-position, 3-position and 5-position of the adamantyl group.

  Among the above, preferable examples of the compound (F) include compounds represented by the following formulas (F1-1) to (F1-5).

The compound (F) is a novel compound.
The manufacturing method of the compound (F) of this invention is not specifically limited, For example, the method shown below is mentioned suitably.
Under anhydrous conditions, particularly under an inert gas atmosphere such as nitrogen or argon, R ⁵⁰ — [C (═O) —OH] _n (where R ⁵⁰ and n are as defined above) is converted to thionyl chloride. to reflux and dissolved in (SOCl ^_2), R 50 - obtain _{[C (= O) -Cl]} n.
Next, in an anhydrous state, particularly in an inert gas atmosphere such as nitrogen or argon, R ^50- [C (= O) -Cl] A solution obtained by dissolving _n in an organic solvent such as tetrahydrofuran is added dropwise.
Next, water is added to the solution after the dropwise addition, the solution is concentrated to dryness, and liquid separation is performed using ethyl acetate or the like to obtain a compound (F).

≪Positive resist composition for immersion exposure≫
The positive resist composition for immersion exposure of the present invention generates a base component (A) (hereinafter referred to as component (A)) whose solubility in an alkaline developer is increased by the action of an acid, and generates an acid upon exposure. The acid generator component (B) (hereinafter referred to as “component (B)”) and the compound (F) represented by the general formula (F1) (hereinafter referred to as “component (F)”) are contained.

<(A) component>
The component (A) is not particularly limited as long as the solubility in an alkaline developer is increased by the action of an acid, and is a base component for a chemically amplified resist composition, such as a resist composition for ArF excimer laser, What is necessary is just to select arbitrarily from many proposed base-material components, such as a resist composition for KrF excimer lasers (preferably a resist composition for ArF excimer lasers).
Here, the “base component” means an organic compound having a film forming ability.
Preferable base material components include organic compounds having a molecular weight of 500 or more. When the molecular weight of the organic compound is 500 or more, the film forming ability is improved and a nano-level pattern is easily formed.
The organic compound having a molecular weight of 500 or more includes a low molecular weight organic compound having a molecular weight of 500 to 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, polymer compound). It is divided roughly. As the low molecular weight compound, a non-polymer is usually used. In the case of a resin (polymer, polymer compound), 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.

  In the positive resist composition for immersion exposure according to the present invention, as the component (A), preferably a base component having an acid dissociable, dissolution inhibiting group and increasing the solubility in an alkali developer by the action of an acid is used. It is done. A resist composition containing such a base component is insoluble in an alkali developer before exposure, and when an acid is generated from the component (B) by exposure during resist pattern formation, acid dissociable dissolution is caused by the action of the acid. The inhibitory group is dissociated, whereby the solubility of the entire component (A) in the alkali developer is increased and the alkali-insoluble is changed to alkali-soluble. 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 turns into alkali-soluble while the unexposed portion is alkali-insoluble. Since it remains unchanged, alkali development can be performed. Thereby, a resist pattern can be formed.

In the positive resist composition for immersion exposure according to the present invention, the component (A) may be referred to as a resin (A1) (hereinafter referred to as component (A1) whose solubility in an alkaline developer is increased by the action of an acid. Or a low molecular compound (A2) (hereinafter sometimes referred to as the component (A2)) whose solubility in an alkali developer is increased by the action of an acid, and a mixture thereof. May be.
In consideration of miscibility with component (F), availability, etc., component (A) is preferably component (A1).

[(A1) component]
As the component (A1), what has been proposed as a base resin for a positive chemically amplified resist can be used. Examples of the base resin include alkali-soluble groups (hydroxyl groups, carboxy groups, etc.). ), A resin in which part or all of the alkali-soluble group in the resin having an acid-dissociable, dissolution-inhibiting group is protected. Examples of the resin having an alkali-soluble group include a novolak resin, a resin having a structural unit derived from hydroxystyrene (polyhydroxystyrene, hydroxystyrene-styrene copolymer, etc.), and a structural unit derived from an acrylate ester. And a resin having a structural unit derived from cycloolefin.
In the present invention, the component (A1) is preferably a resin having a structural unit derived from an acrylate ester. Such a resin is particularly highly transparent to an ArF excimer laser, and can be suitably used in lithography using an ArF excimer laser.
In the component (A1), the proportion of the structural unit derived from the acrylate ester is preferably 20 mol% or more, more preferably 50 mol% or more based on the total of all the structural units constituting the component (A1). More preferably, 80 mol% or more is more preferable, and 100 mol% may be sufficient.

Here, in the present specification and claims, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position Include concepts. Examples of the substituent include a lower alkyl group and a halogenated lower alkyl group. The α-position (α-position carbon atom) of a structural unit derived from an acrylate ester is a carbon atom to which a carbonyl group is bonded unless otherwise specified.
In the acrylate ester, 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.
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, more preferably a hydrogen atom or a lower alkyl group. From the above availability, a hydrogen atom or a methyl group is most preferable.

・ Structural unit (a1)
In the present invention, the component (A1) preferably has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and is dissociated by the action of an acid. A1) 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.

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 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. .
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- A 2-adamantyl group, a 2-ethyl-2-adamantyl group, and the like can be given. 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 may be alkyl groups (both linear and branched, preferably 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, this 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.
As the acetal type acid dissociable, dissolution inhibiting group, the acid dissociable dissolution inhibiting group in the compound according to the first aspect of the present invention described above, the “acetal type acid dissociable, dissolution inhibiting group in a state not substituted with a fluorine atom” And the like.

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

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

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

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^２は酸解離性溶解抑制基を示し；Ｙ^２はアルキレン基また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 ² represents an acid dissociable, dissolution inhibiting group; Y ² represents an alkylene group or 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).
Y ² is preferably an alkylene group having 1 to 10 carbon atoms or a divalent aliphatic cyclic group, and a group in which two or more hydrogen atoms are removed is used as the aliphatic cyclic group. Except for the above, the same “aliphatic cyclic group” as described above can be used.
When Y ² is an alkylene group having 1 to 10 carbon atoms, it is more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. .
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. .

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

［式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５の低級アルキル基、または脂肪族環式基を表し；ｎ’は０〜３の整数を表し；Ｙ^２はアルキレン基または脂肪族環式基を表し；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。］

[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; Y ² represents an alkylene group or an aliphatic cyclic group; R is the same as defined above; and R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. Represents. ]

Wherein, X 'include the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n ', as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1)', R 2 '} , n' , Y and the like.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).

  Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among these, the structural unit represented by general formula (a1-1) is preferable, and specifically, (a1-1-1) to (a1-1-6) and (a1-1-35) to (a1- It is more preferable to use at least one selected from the group consisting of structural units represented by 1-41).
Furthermore, the structural unit (a1) is represented by the following general formula (a1-1-01) that includes the structural units represented by formula (a1-1-1) to formula (a1-1-4). And those represented by the following general formula (a1-1-02) including the structural units represented by the formulas (a1-1-35) to (a1-1-41) 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。）

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

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

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

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

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

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

・ Structural unit (a2)
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.
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.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.

As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, examples of the lactone-containing monocyclic group include groups in which one hydrogen atom has been removed from γ-butyrolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.

  More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり；Ｒ’は水素原子、低級アルキル基、または炭素数１〜５のアルコキシ基であり；ｍは０または１の整数であり；Ａは炭素数１〜５のアルキレン基または酸素原子である。］

[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, or an alkoxy group having 1 to 5 carbon atoms; m is an integer of 0 or 1] A is an alkylene group having 1 to 5 carbon atoms or an oxygen atom. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
The lower alkyl group for R ′ is the same as the lower alkyl group for R in the structural unit (a1).
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 of A include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
Below, the specific structural unit of the said general formula (a2-1)-(a2-5) is illustrated.

  Among these, it is preferable to use at least one selected from structural units represented by general formulas (a2-1) to (a2-5), and in general formulas (a2-1) to (a2-3) It is more preferable to use at least one selected from the structural units represented. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-3-1), (a2-3-2) ), (A2-3-9) and (a2-3-10) are preferably used.

In the component (A1), as the structural unit (a2), one type of structural unit may be used, or two or more types may be used in combination.
The proportion of the structural unit (a2) in the component (A1) is preferably 5 to 60 mol%, more preferably 10 to 60 mol%, with respect to the total of all structural units constituting the component (A1). 55 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 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 unit (a1) and the structural unit (a2). It is preferable to have a structural unit (a3). By having the structural unit (a3), the hydrophilicity of the component (A1) is increased, the affinity with the developer is increased, the solubility in the alkaline developer in the exposed area is improved, and the resolution is improved. Contribute.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, a hydroxyalkyl group, a hydroxyalkyl group in which part of the hydrogen atoms of the alkyl group is substituted with a fluorine atom, and the like, 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, the structural unit represented by the following formula (a3-1), the structural unit represented by the following formula (a3-2), and the following formula The structural unit represented by (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 the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t 'is an integer of 1 to 3, and l is an integer of 1 to 5. And s is an integer of 1 to 3.)

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

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

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

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on all structural units constituting the component (A1). More preferred is ˜25 mol%. By setting it to the lower limit value or more, the effect of containing the structural unit (a3) is 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 not classified into the above structural units (a1) to (a3), and for ArF excimer laser, for 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 for the structural unit (a1), for ArF excimer laser, for KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the base material 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。）

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

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

  In the present invention, the component (A1) is preferably a copolymer having the structural units (a1), (a2) and (a3). Examples of such a copolymer include a copolymer composed of the structural units (a1), (a2) and (a3), and a copolymer composed of the structural units (a1), (a2), (a3) and (a4). A polymer etc. can be illustrated.

  As the component (A1), a copolymer having three structural units represented by the following general formula (A1-11) is particularly preferable.

［式中、Ｒは前記と同じであり、Ｒ^１０は低級アルキル基である。］

[Wherein, R is the same as defined above, and R ¹⁰ represents a lower alkyl group. ]

In formula (A1-11), the lower alkyl group for R ^{10 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably a methyl group.

The component (A1) is obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate. be able to.
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 the 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

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography (GPC)) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 5000. ˜20,000 is most preferred. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and still more preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.

[(A2) component]
The component (A2) is preferably a low molecular compound having a molecular weight of 500 or more and 2000 or less and having an acid dissociable, dissolution inhibiting group and a hydrophilic group as exemplified in the description of the component (A1). Specific examples include those in which a part of the hydrogen atoms of the hydroxyl group of the compound having a plurality of phenol skeletons is substituted with the acid dissociable, dissolution inhibiting group.
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 positive resist composition for immersion exposure according to the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.
In the present invention, the component (A) preferably has no fluorine atom. Since the component (A) does not have a fluorine atom, lithography characteristics are particularly improved.

<(B) component>
(B) It does not specifically limit as a component, What has been proposed as an acid generator for chemical amplification type resists until now 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, poly (bissulfonyl) diazomethanes, and the like. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

  Examples of the onium salt acid generator include compounds represented by the following general formula (b-1) or (b-2).

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基またはアルキル基を表し；式（ｂ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２つが相互に結合して式中のイオウ原子と共に環を形成してもよく；Ｒ^４”は、直鎖状、分岐鎖状または環状のアルキル基またはフッ素化アルキル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

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

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

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

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

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

Specific examples of the onium salt acid generators represented by the formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. 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) phenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenylsulfonium trifluoromethanesulfonate, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydro 1- (4-methylphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutanesulfonate; 1- (thiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutanesulfonate; 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoro Lomethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- 4-ethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutanesulfonate; 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoro L-methane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of 1-phenyltetrahydrothiopyranium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyra Trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutane 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-methylphenyl) tetrahydrothiopyranium Examples thereof include trifluoromethanesulfonate, its heptafluoropropanesulfonate, and its nonafluorobutanesulfonate.
In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

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

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

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms 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, Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less This is preferable because the transparency to the surface is improved.
The proportion 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 hydrogen atoms are substituted with fluorine atoms. A perfluoroalkylene group or a perfluoroalkyl group.

  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 a lower 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, or an isopropyl group. , N-butyl group, or 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.
n ₁ is preferably 0 to 2, more preferably 0 or 1.
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) may be used.
Among these, a fluorinated alkyl sulfonate ion is preferable, a fluorinated alkyl sulfonate ion having 1 to 4 carbon atoms is more preferable, and a linear perfluoroalkyl sulfonate ion having 1 to 4 carbon atoms is particularly preferable. Specific examples include trifluoromethyl sulfonate ion, heptafluoro-n-propyl sulfonate ion, nonafluoro-n-butyl sulfonate ion, 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 or a fluorinated alkyl group having 1 to 4 carbon atoms which has no substituent.

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

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

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

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

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

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

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

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

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

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

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [Chemical 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. It is possible.

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, as the component (B), among the above, it is preferable to use an onium salt having a fluorinated alkyl sulfonate ion as an anion.
(B) Content of a component is 0.5-30 mass parts with respect to 100 mass parts of (A) component, Preferably it is 1-10 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.

<(F) component>
In the positive resist composition for immersion exposure according to the present invention, the component (F) is the same as the compound according to the first aspect of the present invention. By containing the component (F), the effect of having hydrophobicity suitable for immersion exposure can be obtained. And the water follow-up property that the immersion medium moves following the movement of the lens is improved.

As the component (F), it is preferable that R ⁵⁰ in the general formula (F1) is a saturated hydrocarbon group or an aromatic group because the effect of the present invention is excellent. In addition, it is also preferable that X in the general formula (F1) is a group represented by the general formula (F1-1-1).
In the present invention, the component (F) is preferably at least one selected from the compounds represented by the formulas (F1-1) to (F1-5), and the formula (F1-1) to Particularly preferred is at least one selected from the compounds represented by formula (F1-4).

(F) A component may be used individually by 1 type and may be used in combination of 2 or more type.
(F) It is preferable that the content rate of a component is 0.01-10 mass parts with respect to 100 mass parts of (A) component, It is more preferable that it is 0.1-7 mass parts, 0.3- It is particularly preferably 6 parts by mass, and most preferably 0.4-5 parts by mass. By setting the lower limit value or more, the effect of improving the hydrophobicity of the resist composition is excellent, and by setting the upper limit value or less, the lithography characteristics are improved.

<(D) component>
The positive resist composition for immersion exposure according to the present invention preferably further contains a nitrogen-containing organic compound (D) (hereinafter referred to as component (D)) as an optional component. As a result, the resist pattern shape, the stability over time and the like are improved.
Since a wide variety of component (D) has already been proposed, any known one can be used. Among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are used. preferable. An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, and the like; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, tri-n-pentylamine and tri-n-octylamine are particularly preferable, and tri-n-pentylamine is most preferable.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
As the component (D), any one type may be used alone, or two or more types may be used in combination.
When the component (D) is contained in the resist composition, the component (D) is usually used in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A).

<Optional component>
[(E) component]
The positive resist composition for immersion exposure of the present invention includes an organic carboxylic acid and phosphorus oxo as optional components for the purpose of preventing sensitivity deterioration and improving the resist pattern shape and stability with time. At least one compound (E) selected from the group consisting of an acid and a derivative thereof (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 phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
As the component (E), one type may be used alone, or two or more types may be used in combination.
As the component (E), an organic carboxylic acid is preferable, and salicylic acid is particularly preferable.
When the component (E) is contained in the resist composition, the component (E) is usually used at a ratio of 0.01 to 5.0 parts by mass per 100 parts by mass of the component (A).

  The positive resist composition for immersion exposure according to the present invention may further contain miscible additives, for example, an additional resin for improving the performance of the resist film and a surfactant for improving the coating property. Further, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

[(S) component]
The positive resist composition for immersion exposure of the present invention can be produced by dissolving a material in an organic solvent (hereinafter 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 and derivatives thereof; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether of the polyhydric alcohols or the compound having an ester bond , Monoalkyl ethers such as monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether Derivatives of polyhydric alcohols such as compounds having an ether bond such as propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred among them; cyclic ethers such as dioxane, , Methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, etc .; anisole, ethyl benzyl ether, cresyl methyl Ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene An aromatic organic solvent such as
These organic solvents may be used alone or as a mixed solvent of two or more. Of 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, but is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. is there.
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 99: 1.
Furthermore, as the component (S), a mixed solvent of the above-described mixed solvent of PGMEA and PGME and γ-butyrolactone is also preferable.
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 dissolution of the material in the component (S) can be carried out, for example, by simply mixing and stirring each of the above components by a conventional method, and if necessary, a disperser such as a dissolver, a homogenizer, or a three roll mill. May be dispersed and mixed. Moreover, after mixing, you may further filter using a mesh, a membrane filter, etc.

The positive resist composition for immersion exposure according to the present invention has a hydrophobic property suitable for immersion exposure, which is a characteristic required for a resist composition used for immersion exposure. Preferably used.
That is, as described above, the immersion exposure is performed by exposing the portion between the lens and the resist film on the wafer, which is conventionally filled with an inert gas such as air or nitrogen, at a time higher than the refractive index of air. This is a method including a step of performing exposure (immersion exposure) in a state filled with a solvent (immersion medium) having a large refractive index. In immersion exposure, when the resist film and the immersion solvent come into contact with each other, elution (substance elution) of substances ((B) component, (D) component, etc.) in the resist film into the immersion solvent occurs. Substance elution causes phenomena such as alteration of the resist layer and change in the refractive index of the immersion solvent, thereby deteriorating the lithography properties. The amount of this substance elution is affected by the characteristics of the resist film surface (for example, hydrophilicity / hydrophobicity). Therefore, for example, it is presumed that elution of the substance is reduced by increasing the hydrophobicity of the resist film surface.
The positive resist composition for immersion exposure according to the present invention contains the compound (F) having an ester bond in the molecule and containing an acid dissociable, dissolution inhibiting group having a fluorine atom. Compared with the case where F) is not contained, the hydrophobicity of the resist film formed using the said resist composition is high. Therefore, according to the positive resist composition for immersion exposure of the present invention, it is expected that substance elution during immersion exposure can be suppressed.
Moreover, the positive resist composition for immersion exposure according to the present invention also has various lithography properties. For example, by using the positive resist composition for immersion exposure according to the present invention, a fine resist pattern having a line width of a line and space (L / S) pattern of 120 nm or less can be formed.

The resist film formed by using the positive resist composition for immersion exposure according to the present invention contains the (F) component, so that the hydrophobicity of the resist film compared to the case where the (F) component is not contained. The contact angle against water, for example, the static contact angle (the angle between the water droplet surface on the horizontal resist film and the resist film surface), the dynamic contact angle (when the resist film is tilted, The contact angle (falling angle) when it starts to fall, the contact angle (advance angle) at the end point in the forward direction of the drop of water, and the contact angle (retreat angle) at the end point in the rearward direction of the drop) change. For example, the higher the hydrophobicity of the resist film, the larger the static contact angle, the advancing angle, and the receding angle, while the smaller the falling angle.
Here, as shown in FIG. 1, when the plane 2 on which the droplet 1 is placed is gradually tilted, the advancing angle starts to move (drop) on the plane 2 when the plane 1 is gradually inclined. Is the angle θ ₁ formed by the surface of the droplet at the lower end 1 a of the droplet 1 and the plane 2. At this time (when the droplet 1 starts to move (drop) on the plane 2), an angle θ2 formed by the droplet surface at the upper end 1b of the droplet 1 and the plane ₂ is a receding angle, The inclination angle θ _{3 of the} plane 2 is the falling angle.
In the present specification, the static contact angle, the advancing angle, the receding angle, and the falling angle are measured, for example, as follows.
First, a resist composition solution is spin-coated on a silicon substrate, and then heated at 110 ° C. for 60 seconds to form a resist film.
Next, with respect to the resist film, DROP MASTER-700 (product name, manufactured by Kyowa Interface Science Co., Ltd.), AUTO SLIDING ANGLE: SA-30DM (product name, manufactured by Kyowa Interface Science Co., Ltd.), AUTO DISPENSER: AD-31 ( It can be measured using a commercially available measuring device such as a product name (manufactured by Kyowa Interface Science Co., Ltd.).

In the positive resist composition for immersion exposure according to the present invention, the measured value of the receding angle in a resist film obtained using the resist composition is preferably 50 ° or more, more preferably 50 to 150 °. 50 to 130 ° is particularly preferable, and 53 to 100 ° is most preferable. When the receding angle is at least the lower limit value, the substance elution suppressing effect during immersion exposure is improved. The reason for this is not clear, but one of the main factors may be related to the hydrophobicity of the resist film. In other words, since the aqueous immersion medium is an aqueous medium such as water, it is highly hydrophobic, so that the immersion medium is quickly removed from the resist film surface when the immersion medium is removed after immersion exposure. It is presumed that the fact that it can be removed is affected. Further, when the receding angle is not more than the upper limit value, the lithography characteristics and the like are good.
For the same reason, the positive resist composition for immersion exposure according to the present invention preferably has a measured value of a static contact angle in a resist film obtained by using the resist composition of 60 ° or more, 63 More preferably, it is -95 degrees, and it is especially preferable that it is 65-95 degrees.
In the positive resist composition for immersion exposure according to the present invention, the measured value of the falling angle in a resist film obtained using the resist composition is preferably 36 ° or less, and preferably 10 to 36 °. Is more preferable, 7 to 30 ° is particularly preferable, and 14 to 27 ° is most preferable. When the sliding angle is less than or equal to the upper limit value, the substance elution suppression effect during immersion exposure is improved. Further, when the sliding angle is at least the lower limit value, the lithography properties and the like are good.

  The above-mentioned various angles (dynamic contact angles (advance angle, receding angle, sliding angle, etc.) are determined depending on the composition of the positive resist composition for immersion exposure, for example, the blending amount of the component (F) and the general formula. It can be adjusted by adjusting the value of n in (F1), the type of component (A), etc. For example, the higher the content ratio of component (F), the higher the hydrophobicity of the resulting resist composition, resulting in static contact. The corner becomes larger.

Further, in the present invention, as described above, it is expected that substance elution from the resist film during immersion exposure to the immersion solvent is suppressed. Therefore, in the immersion exposure, by using the positive resist composition for immersion exposure according to the present invention, it is possible to suppress the alteration of the resist film and the change in the refractive index of the immersion solvent. Accordingly, the shape of the resist pattern to be formed is improved, for example, by suppressing fluctuations in the refractive index of the immersion solvent.
In addition, contamination of the lens of the exposure apparatus can be reduced, and therefore protection measures for these can be omitted, contributing to simplification of the process and the exposure apparatus.
Further, as described above, when performing immersion exposure using a scanning immersion exposure machine as described in Non-Patent Document 1, the immersion medium moves following the movement of the lens. In the present invention, the resist film has high hydrophobicity and high water followability. Moreover, the positive resist composition for immersion exposure according to the present invention has good lithography characteristics, and can be used to form a resist pattern without any practical problems when used as a resist in immersion exposure.
As described above, the positive resist composition for immersion exposure according to the present invention has good lithography properties (sensitivity, resolution, etc.), as well as hydrophobicity, substance elution suppression ability, water followability, etc. It is excellent and has sufficient characteristics required for a resist material in immersion exposure.

≪Resist pattern formation method≫
Next, the resist pattern forming method of the present invention will be described.
The resist pattern forming method of the present invention includes a step of forming a resist film on a support using the positive resist composition for immersion exposure of the present invention, a step of immersing the resist film, and the resist film A step of forming a resist pattern by alkali development.

A preferred example of the method for forming a resist pattern of the present invention is shown below.
First, after applying the positive resist composition for immersion exposure of the present invention on a support with a spinner or the like, for example, pre-baking (post-apply baking (PAB) treatment) is performed at a temperature of 80 to 150 ° C. for 40 to 40 ° C. A resist film is formed by applying for 120 seconds, preferably 60 to 90 seconds.
The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include organic films such as an organic antireflection film (organic BARC) and a lower organic film in a multilayer resist method.
Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the resist pattern formed on the upper resist film is used as a mask. This is a method of patterning a lower organic film, and it is said that a pattern with a high aspect ratio can be formed. That is, according to the multilayer resist method, the required thickness can be secured by the lower organic film, so that the resist film can be thinned and a fine pattern with a high aspect ratio can be formed.
In the multilayer resist method, basically, a method of forming a two-layer structure of an upper resist film and a lower organic film (two-layer resist method), and one or more intermediate layers between the upper resist film and the lower organic film And a method of forming a multilayer structure of three or more layers (metal thin film etc.) (three-layer resist method).

  After the resist film is formed, an organic antireflection film may be further provided on the resist film to form a three-layer laminate including a support, a resist film, and an antireflection film. The antireflection film provided on the resist film is preferably soluble in an alkali developer.

  The steps so far can be performed using a known method. The operating conditions and the like are preferably set as appropriate according to the composition and characteristics of the positive resist composition for immersion exposure to be used.

Next, liquid immersion lithography is selectively performed on the resist film obtained above through a desired mask pattern. At this time, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index larger than that of air, and exposure (immersion exposure) is performed in this state.
The wavelength used for the exposure is not particularly limited, and can be performed using radiation such as an ArF excimer laser, a KrF excimer laser, or an F ₂ laser. The resist composition according to the present invention is effective for a KrF or ArF excimer laser, particularly an ArF excimer laser.

As the immersion medium, a solvent having a refractive index that is larger than the refractive index of air and smaller than the refractive index of the resist film formed by using the positive resist composition for immersion exposure of the present invention is preferable. . The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorinated inert liquid include fluorinated compounds such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as main components. Examples thereof include liquids, and those having a boiling point of 70 to 180 ° C are preferable, and those having a boiling point of 80 to 160 ° C are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).
In the present invention, water is preferably used as the immersion medium because the positive resist composition for immersion exposure of the present invention is not particularly adversely affected by water and is excellent in sensitivity and resist pattern profile shape. Water is also preferable from the viewpoints of cost, safety, environmental problems, and versatility.

  Next, after the immersion exposure process is completed, post-exposure heating (post-exposure baking (PEB)) is performed for 40 to 120 seconds, preferably 60 to 90 seconds, for example, under a temperature condition of 80 to 150 ° C., followed by an alkaline aqueous solution. Development processing is carried out using an alkaline developer comprising And preferably, water rinsing is performed using pure water. The water rinsing can be performed, for example, by dropping or spraying water on the substrate surface while rotating the substrate, and washing away the developer on the substrate and the positive resist composition for immersion exposure dissolved by the developer. Then, drying is performed to obtain a resist pattern in which a resist film (a coating film of a positive resist composition for immersion exposure) is patterned into a shape corresponding to the mask pattern.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
≪Synthesis of compounds≫
Compounds (F1-1) to (F1-4) were obtained by the synthesis examples of Examples 1 to 4 shown below.

(Example 1: Synthesis example of compound (F1-1))
Compound (F1-1) was synthesized by the following synthesis route.

[Synthesis of Adamantane Carbonyl Chloride (Compound 2)]
Under a nitrogen atmosphere, Compound 1 (10.00 g, 55.52 mmol) was dissolved in 45 ml of thionyl chloride (SOCl ₂ ). Subsequently, it was refluxed at 90 ° C. for 5 hours with stirring. Thereafter, the solution was vacuum-dried to obtain adamantane carbonyl chloride (Compound 2).

Under a nitrogen atmosphere, compound 2 (3.0 g 15.10 mmol) was added to a solution of compound 3 fluoroalcohol (3.04 g, 15.31 mmol) and triethylamine (3.098 g, 30.62 mmol) in 20 ml of THF. A solution dissolved in 20 ml of THF was added dropwise under ice cooling. Then, it returned to normal temperature and stirred. After 12 hours, water was added and the solution was concentrated to dryness. This was liquid-separated using ethyl acetate, the organic phase was obtained, and the compound (F1-1) was obtained by drying this.
The obtained compound (F1-1) was analyzed by ¹ H-NMR. The results are shown below.
¹ H-NMR (CDCl ₃ , 400 MHz): δ (ppm) 1.42-2.20 (m, 21H), 0.87 (t, 6H, H)

(Example 2: Synthesis example of compound (F1-2))
Compound (F1-2) was synthesized by the following synthesis route.

[Synthesis of Adamantane Dicarbonyl Chloride (Compound 5)]
Under a nitrogen atmosphere, adamantane 1,3-dicarboxylic acid (10.00 g, 44.59 mmol) was dissolved in 45 ml of thionyl chloride (SOCl ₂ ). Subsequently, it was refluxed at 90 ° C. for 5 hours with stirring. Thereafter, the solution was vacuum-dried to obtain adamantane dicarbonyl chloride (Compound 5).

Under a nitrogen atmosphere, Compound 5 (3.0 g, 11.49 mmol) was dissolved in a solution of Compound 3 fluoroalcohol (3.04 g, 15.31 mmol) and triethylamine (3.098 g, 30.62 mmol) in 20 ml of THF. Was added dropwise in ice-cooling. Then, it returned to normal temperature and stirred. After 12 hours, water was added and the solution was concentrated to dryness. This was separated using ethyl acetate to obtain an organic phase, which was dried to obtain a compound (F1-2).
The obtained compound (F1-2) was analyzed by ¹ H-NMR. The results are shown below.

¹ H-NMR (CDCl ₃ , 400 MHz): δ (ppm) 2.22 (m, 2H, Ha), 1.92 (m, 8H, Hb), 1.71 (m, 2H, Hc), 2. 08 (m, 4H, Hg), 1.60 (m, 4H, Hf), 1.47 (m, 12H, He), 0.87 (t, 12H, Hd)
From the results shown above, it was confirmed that the compound (F1-2) had a structure shown below.

(Example 3: Synthesis example of compound (F1-3))
Compound (F1-3) was synthesized by the following synthesis route.

Under a nitrogen atmosphere, a solution of compound 3 in a solution of fluorine alcohol (2.64 g) and triethylamine (1.40 g) in 20 ml of THF and a solution of compound 6 (2.97 g) in 20 ml of THF are cooled in ice. It was dripped. Then, it returned to normal temperature and stirred. After 12 hours, water was added and the solution was concentrated to dryness. This was separated using ethyl acetate to obtain an organic phase, which was dried to obtain a compound (F1-3).
The obtained compound (F1-3) was analyzed by ¹ H-NMR. The results are shown below.

¹ H-NMR (CDCl ₃ , 400 MHz): δ (ppm) 0.9 (m, 9H, Ha), 1.3 (m, 8H, Hb), 1.4-1.6 (m, 4H, Hc) ), 1.8 (t, 2H, Hd), 2.1 (m, 4H, He), 2.45 (t, 2H, Hf)
From the results shown above, it was confirmed that the compound (F1-3) had a structure shown below.

(Example 4: Synthesis example of compound (F1-4))
Compound (F1-4) was synthesized by the following synthesis route.

Under a nitrogen atmosphere, a solution of Compound 7 in 1,6-hexylene-dibenzene was added to a solution of Compound 3 fluoroalcohol (3.04 g, 15.31 mmol) and triethylamine (3.098 g, 30.62 mmol) in 20 ml of THF. A solution of carbonyl chloride (6.0 g, 10.94 mmol) dissolved in 20 ml of THF was added dropwise in an ice bath. Then, it returned to normal temperature and stirred. After 12 hours, water was added and the solution was concentrated to dryness. This was liquid-separated using ethyl acetate, the organic phase was obtained, and the compound (F1-4) was obtained by drying this.
The obtained compound (F1-4) was analyzed by ¹ H-NMR. The results are shown below.

¹ H-NMR (CDCl ₃ , 400 MHz): δ (ppm) 2.1-1.9 (m, 8H, Ha), 1.7-1.5 (m, 16H, Hb), 1.3-1. .1 (m, 8H, Hc), 0.9-0.7 (m, 12H, Hd)
From the results shown above, it was confirmed that the compound (F1-4) had a structure shown below.

≪Preparation and evaluation of positive resist composition≫
As the component (F) in Examples 5 to 8, the compounds (F1-1) to (F1-4) synthesized according to the synthesis examples of Examples 1 to 4 were used.
Further, in Examples 5 to 8 and Comparative Example 1, the resin (A) -1 used as the component (A) was copolymerized by a known dropping polymerization method using the following monomers (1) to (3). I got it.

GPC measurement was performed on the obtained resin (A) -1, and the mass average molecular weight (Mw) and the dispersity (Mw / Mn) were determined. The Mw was 7000 and the Mw / Mn was 1.8.
The structure of Resin (A) -1 is shown below. In the formula, the number attached to the lower right of () indicates the ratio (mol%) of each structural unit to the total of all structural units constituting the polymer compound. The proportion of each structural unit was calculated by carbon NMR.

<Preparation of positive resist composition>
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A) -1: the resin (A) -1.
(B) -1: (4-methylphenyl) diphenylsulfonium nonafluoro-n-butanesulfonate.
(F) -1: Compound (F1-1).
(F) -2: the compound (F1-2).
(F) -3: The compound (F1-3).
(F) -4: The compound (F1-4).
(D) -1: tri-n-pentylamine.
(S) -1: PGMEA.

  Using the obtained positive resist composition, the hydrophobicity of the resist film was evaluated by measuring the static contact angle of the resist film surface before exposure in the following procedure.

<Evaluation of hydrophobicity of resist film>
A positive resist composition having the composition shown in Table 1 was applied onto an 8-inch silicon wafer using a spinner, pre-baked on a hot plate at 110 ° C. for 60 seconds, and dried to thereby form a film having a thickness of 120 nm. A resist film was formed.
By dropping 2 μL of water onto the surface of the resist film (resist film before exposure) and measuring the static contact angle using DROP MASTER-700 (product name, manufactured by Kyowa Interface Science Co., Ltd.), the resist The hydrophobicity of the membrane was evaluated. The results are shown in Table 2.

From the results of Table 2, the resist films obtained using the positive resist compositions of Examples 5 to 8 have a static contact angle larger than that of the resist film obtained using the positive resist composition of Comparative Example 1. Since the value was large, it was confirmed that the film was highly hydrophobic.
Therefore, it was confirmed that the positive resist compositions of Examples 5 to 8 according to the present invention were suitable for immersion exposure.

<Lithography evaluation>
An organic antireflective coating composition “ARC95” (trade name, manufactured by Brewer Science) is applied onto an 8-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 77 nm was formed.
Then, the positive resist composition shown in Table 1 above was applied onto the organic antireflection film using a spinner, and a prebake (PAB) treatment was performed on a hot plate at 110 ° C. for 60 seconds. By drying, a resist film having a film thickness of 150 nm was formed.
Next, an ArF excimer laser (193 nm) was selectively irradiated through the mask pattern by an ArF exposure apparatus NSR-S302 (manufactured by Nikon; NA (numerical aperture) = 0.60, 2/3 annular illumination). . Then, a post-exposure heating (PEB) treatment was performed at 110 ° C. for 60 seconds, followed by development with an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution at 23 ° C. for 30 seconds. Water rinsing was performed using water, followed by shaking off and drying.
As a result, a line and space resist pattern (L / S pattern) having a line width of 120 nm and a pitch of 240 nm was formed in any of the examples using the positive resist composition.

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

Explanation of symbols

1 droplet 1a lower end 1b upper end 2 plane θ ₁ advancing angle θ ₂ receding angle θ ₃ falling angle

Claims (13)

The compound represented by the following general formula (F1).

[In formula (F1), X represents an acid dissociable, dissolution inhibiting group having a fluorine atom; n represents an integer of 1 to 4. R ⁵⁰ is an n-valent organic group and may have a substituent. However, when n is 1, R ⁵⁰ is an organic group containing no polymerizable group. ] The compound according to claim 1, wherein R ⁵⁰ is a saturated hydrocarbon group or an aromatic group. The compound according to claim 1 or 2, wherein X is a group represented by the following general formula (F1-1-1).

[In Formula (F1-1-1), R ^{1 to} R ³ are each independently an alkyl group or a fluorinated alkyl group, and the fluorinated alkyl group is a ^third bonded to R ^{1 to} R ³ . The carbon atom adjacent to the secondary carbon atom is a group in which no fluorine atom is bonded, and at least one of R ^{1 to} R ³ is the fluorinated alkyl group. However, R ² and R ³ may be bonded to each other to form one ring structure composed of R ² , R ³ and the tertiary carbon atom. ] A base component (A) whose solubility in an alkaline developer is increased by the action of an acid, an acid generator component (B) that generates an acid upon exposure, and a compound (F) represented by the following general formula (F1) And a positive resist composition for immersion exposure.

[In formula (F1), X represents an acid dissociable, dissolution inhibiting group having a fluorine atom; n represents an integer of 1 to 4. R ⁵⁰ is an n-valent organic group and may have a substituent. However, when n is 1, R ⁵⁰ is an organic group containing no polymerizable group. ] The positive resist composition for immersion exposure according to claim 4, wherein R ⁵⁰ is a saturated hydrocarbon group or an aromatic group. The positive resist composition for immersion exposure according to claim 4 or 5, wherein X is a group represented by the following general formula (F1-1-1).

[In Formula (F1-1-1), R ^{1 to} R ³ are each independently an alkyl group or a fluorinated alkyl group, and the fluorinated alkyl group is a ^third bonded to R ^{1 to} R ³ . The carbon atom adjacent to the secondary carbon atom is a group in which no fluorine atom is bonded, and at least one of R ^{1 to} R ³ is the fluorinated alkyl group. However, R ² and R ³ may be bonded to each other to form one ring structure composed of R ² , R ³ and the tertiary carbon atom. ]   The content rate of the said compound (F) is 0.01-10 mass parts with respect to 100 mass parts of said base-material components (A), The positive for immersion exposure as described in any one of Claims 4-6. Type resist composition.   The positive resist composition for immersion exposure according to any one of claims 4 to 7, wherein the substrate component (A) is a resin (A1) whose solubility in an alkaline developer is increased by the action of an acid. .   The positive resist composition for immersion exposure according to claim 8, wherein the resin (A1) has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.   The positive resist composition for immersion exposure according to claim 9, wherein the resin (A1) further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.   The positive resist composition for immersion exposure according to claim 9 or 10, wherein the resin (A1) further comprises a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.   The positive resist composition for immersion exposure according to any one of claims 4 to 11, comprising a nitrogen-containing organic compound (D).   A step of forming a resist film on a support using the positive resist composition for immersion exposure according to any one of claims 4 to 12, a step of immersion exposure of the resist film, and the resist film A resist pattern forming method including a step of forming a resist pattern by alkali development.

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