JP4980040B2 - Resist coating film forming material and resist pattern forming method - Google Patents

Description

  The present invention relates to a resist coating film forming material and a resist pattern forming method.

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

Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions. As a resist material satisfying such requirements, a chemically amplified resist containing a base resin whose alkali solubility is changed by the action of an acid and an acid generator that generates an acid upon exposure is used.
The reaction mechanism of the chemically amplified resist is that an acid is generated from an acid generator upon exposure, and the alkali solubility of the base resin is changed by the action of the acid. For example, in the case of a positive type, a resin having an acid dissociable, dissolution inhibiting group that is dissociated by the action of an acid generated from an acid generator is generally used as the base resin, and when an acid acts on the resin, The acid dissociable, dissolution inhibiting group is dissociated, and the alkali solubility of the resin is increased.
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 the mainstream (see, for example, Patent Document 1). “(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) acrylate ester means one or both of an acrylate ester having a hydrogen atom bonded to the α-position and a methacrylate ester having a methyl group bonded to the α-position.“ (Meth) acrylate ” , 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 methods for further improving the resolution, exposure (immersion exposure) is performed by interposing a liquid (immersion medium) having a higher refractive index than air between the objective lens of the exposure machine and the sample. A so-called immersion lithography (hereinafter referred to as “immersion exposure”) is known (for example, see Non-Patent Document 1).
According to immersion exposure, even when a light source having the same exposure wavelength is used, the same high resolution as when using a light source with a shorter wavelength or 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 forming 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.

Conventionally, a method of forming a resist pattern by providing a coating film (resist coating film) on a resist film has also been performed. The resist coating film is generally used for the purpose of protecting the resist film, improving etching resistance, and an upper antireflection film. In immersion exposure, a resist coating film is provided as a protective film (top coat) that prevents lens contamination of the exposure apparatus due to a sublimation substance (degassing) from the resist film. Currently used resist coating films are roughly classified into those soluble in a developer (alkaline aqueous solution) and those insoluble.
In general, a resin having a completely different structure from the resin component used for the resist film is used for the resist coating film in order to prevent mixing with the resist film. For example, when an ArF excimer laser is used as a light source, an acrylic resin is mainly used for the resist film (see, for example, Patent Document 1), while a main chain ring type is mainly used for the resist coating film. Resin is used. For example, in Patent Documents 2 to 3, as a resist coating film used in immersion exposure using an ArF excimer laser as a light source, -Q-NH-SO ₂ -R ⁵ (where Q is a straight chain having 1 to 5 carbon atoms). A chain or branched alkylene group, and R ⁵ is a fluorinated alkyl group.), A group represented by —CO—O—R ⁷ (wherein R ⁷ is a fluorinated alkyl group). A protective film or the like formed from a composition obtained by dissolving a main chain cyclic resin in an organic solvent is disclosed. Here, the “main chain cyclic resin” means that the structural unit constituting the resin has a monocyclic or polycyclic ring structure, and at least one, preferably 2 on the ring of the ring structure. It means that one or more carbon atoms have a structural unit constituting the main chain (hereinafter referred to as “main chain cyclic structural unit”). Examples of main chain cyclic structural units include structural units derived from polycycloolefins (polycyclic olefins), dicarboxylic anhydride-containing structural units, and the like.
JP 2003-241385 A International Publication No. 06/091523 Pamphlet WO 06/091802 pamphlet Proceedings of SPIE, 5754, 119-128 (2005).

However, the conventional resist coating film has various problems. For example, when the resist coating film is insoluble in alkali, the resist coating film is formed on the resist film after exposure and before development with a developer (alkaline aqueous solution) when forming a resist pattern. It is necessary to peel off cleanly, and it is necessary to consider the influence on the environment.
Further, when the resist coating film is alkali-soluble, there are problems that the lithography characteristics such as the shape of the resist pattern to be formed are deteriorated, and defects (defects) are easily generated on the surface of the resist pattern. Defects are general defects detected when a developed resist pattern is observed from directly above, for example, with a surface defect observation apparatus (trade name “KLA”) manufactured by KLA Tencor. Examples of such defects include scum, bubbles, dust, bridges (bridge structures between resist patterns), uneven color, and precipitates after development. Furthermore, such an alkali-soluble coating film is less useful in immersion exposure performed using an immersion medium such as water.
One of the causes of these problems is that the resin used for the resist coating film is of a different type from the resin used for the resist film. May be bad. Therefore, in order to avoid the above problem, it is possible to use the same kind of resin (acrylic resin) as the resin component used in the resist film, but simply using an acrylic resin on the resist film. When the organic solvent solution of the resin is applied, the resist film dissolves, resulting in problems such as a decrease in the thickness of the resist film and a complete dissolution of the resist film. It is difficult to form a cover film.
The present invention has been made in view of the above circumstances, and a resist coating film forming material capable of forming a coating film on the resist film without impairing lithography properties, and the resist coating film forming material An object of the present invention is to provide a method for forming a resist pattern using the above.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり；Ｙ ^１ は脂肪族環式基であり；Ｚは有機基であり；ａは１〜３の整数であり、ｂは０〜２の整数であり、かつａ＋ｂ＝１〜３であり；ｃ、ｄ、ｅはそれぞれ独立して０〜３の整数である。］ As a result of intensive studies, the present inventors have found that the above problems can be solved by a material obtained by dissolving a specific resin component in a specific organic solvent, and have completed the present invention.
That is, the first aspect of the present invention is a resist coating film forming material formed by dissolving at least a resin component (A) whose alkali solubility is increased by the action of an acid in an organic solvent (S),
The resin component (A) has a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester having an acid dissociable, dissolution inhibiting group. And
Resist coating film formation characterized in that the organic solvent (S) contains at least one organic solvent (S1) selected from the group consisting of an ether-based organic solvent having no hydroxyl group and an alcohol-based solvent Material.

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; Y ¹ is an aliphatic cyclic group; Z is an organic group; a is an integer of 1 to 3; Is an integer from 0 to 2 and a + b = 1 to 3; c, d and e are each independently an integer from 0 to 3. ]

Also, a second aspect of the present invention comprises a support, a chemically amplified resist composition using the process of forming a resist film, the resist film resist coating film formed of the first state-like on Forming a resist coating film using a material for forming a resist laminated body, exposing the resist laminated body, and applying a development process to the resist laminated body to form a resist pattern It is the resist pattern formation method containing.

In the present specification and claims, the “structural unit” means a monomer unit (monomer unit) constituting a resin (polymer, copolymer).
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
The “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups unless otherwise specified.
The “lower alkyl group” is an alkyl group having 1 to 5 carbon atoms.
“Exposure” is a concept that includes general irradiation of radiation.

  According to the present invention, a resist coating film forming material capable of forming a coating film on a resist film without impairing the lithography properties, and a resist pattern forming method using the resist coating film forming material can be provided.

≪Material for resist coating film formation≫
In the resist coating film forming material of the present invention, at least the resin component (A) whose alkali solubility is increased by the action of an acid (hereinafter referred to as component (A)) is an organic solvent (S) (hereinafter referred to as (S ) Component)).

<(A) component>
In the present invention, the component (A) has a structural unit (a) derived from an acrylate ester. Thereby, a resist coating film having a good matching with the resist film can be formed.
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.
Unless otherwise specified, “acrylic acid ester” includes an acrylic acid ester in which a hydrogen atom is bonded to the α-position carbon atom, and a substituent (an atom or group other than a hydrogen atom) on the α-position carbon atom. The concept includes those that are combined. 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.
Examples of the substituent which may be bonded to the α-position carbon atom (α-position substituent) include a lower alkyl group and a halogenated lower alkyl group.
Specific examples of the lower alkyl group as a substituent at the α-position 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 lower linear or branched alkyl group.
Examples of the halogenated lower alkyl group as the substituent at the α-position include groups in which part or all of the hydrogen atoms in the lower alkyl group have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
In the present invention, the α-position of the acrylate ester is preferably a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and is a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group. In view of industrial availability, a hydrogen atom or a methyl group is most preferable.
In the component (A), the proportion of the structural unit derived from the acrylate ester is preferably 50 to 100 mol%, more preferably 75 to 100 mol%, based on the total of all the structural units constituting the component (A). 100 mol% is particularly preferred.

  In the present invention, the component (A) includes a structural unit (a0) represented by the following general formula (a0-1), and a structural unit (a1) derived from an acrylate ester having an acid dissociable, dissolution inhibiting group. It is preferable to have. The component (A) is excellent in solubility in the component (S1), and the formed resist coating film has advantages such as excellent hydrophobicity and substance blocking properties. Such a resist coating film is preferably used in immersion exposure applications.

［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；Ｙ^１は脂肪族環式基であり；Ｚは有機基であり；ａは１〜３の整数であり、ｂは０〜２の整数であり、かつａ＋ｂ＝１〜３であり；ｃ、ｄ、ｅはそれぞれ独立して０〜３の整数である。］

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; Y ¹ is an aliphatic cyclic group; Z is an organic group; a is an integer of 1 to 3; Is an integer from 0 to 2 and a + b = 1 to 3; c, d and e are each independently an integer from 0 to 3. ]

[Structural unit (a0)]
In general formula (a0-1), R represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group.
The lower alkyl group or halogenated lower alkyl group for R is the same as the lower alkyl group or halogenated lower alkyl group which may be bonded to the α-position of the acrylate ester. Among them, R is preferably a hydrogen atom or a methyl group.

In general formula (a0-1), Y ¹ represents 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 a group, a compound, or the like that does not have aromaticity. The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a0) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
The structure of the basic ring (aliphatic ring) excluding the substituent of “aliphatic cyclic group” is not limited to being a ring composed of carbon and hydrogen (hydrocarbon ring), but is a hydrocarbon ring. It is preferable. The “hydrocarbon ring” may be either saturated or unsaturated, but is usually preferably saturated.
The aliphatic cyclic group may be either a polycyclic group or a monocyclic group. Specific examples of the aliphatic cyclic group include, for example, a monocycloalkane, bicycloalkane, tricycloalkane, which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group, Examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as tetracycloalkane. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
The aliphatic cyclic group in the structural unit (a0) is preferably a polycyclic group, and among them, a group obtained by removing two or more hydrogen atoms from adamantane is preferable.

In the general formula (a0-1), Z is an organic group.
Here, the “organic group” is a group containing a carbon atom and at least one other type of atom.
Basically, the organic group is preferably a group containing carbon and hydrogen as main constituent elements, for example, a hydrocarbon group; a group in which some or all of the hydrogen atoms of the hydrocarbon group are substituted with substituents; a hydrocarbon group And a group in which a part of the carbon atom is substituted with another atom or group other than a carbon atom and a hydrogen atom.
The hydrocarbon group may be a chain hydrocarbon group, a cyclic hydrocarbon group, or a group composed of a chain hydrocarbon group and a cyclic hydrocarbon group. Good. The hydrocarbon group is preferably an aliphatic hydrocarbon group, and more preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms.
The substituent is not particularly limited as long as it is an atom or group other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom (═O), a carboxy group, a hydroxyl group, and a cyano group.
Examples of the other atom or group in which part of the carbon atom of the hydrocarbon group may be substituted include an oxygen atom (—O—), a sulfur atom (—S—), a carbonyl group, and a carbonyloxy group. It is done.
As the organic group for Z, a group containing an alkyl group in the structure (an alkyl group-containing group) is particularly preferable.
Here, in the present specification and claims, the “alkyl group” represents a monovalent saturated hydrocarbon group as described above, and is a chain (straight chain or branched chain) alkyl group or cyclic. It includes an alkyl group having a structure.
Examples of the alkyl group in the alkyl group-containing group include linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms.

As the alkyl group-containing group, a tertiary alkyl group-containing group or an alkoxyalkyl group is particularly preferable.
Here, in the present specification and claims, the “tertiary alkyl group” refers to an alkyl group having a tertiary carbon atom.
The “tertiary alkyl group-containing group” refers to a group containing a tertiary alkyl group in its structure. The tertiary alkyl group-containing group may be composed only of a tertiary alkyl group, or may be composed of a tertiary alkyl group and another atom or group other than the tertiary alkyl group. .
Examples of the “atom or group other than the tertiary alkyl group” that constitutes the tertiary alkyl group-containing group together with the tertiary alkyl group include a carbonyloxy group, a carbonyl group, an alkylene group, an oxygen atom, and the like. .

Examples of the tertiary alkyl group-containing group for Z include a tertiary alkyl group-containing group having no cyclic structure, a tertiary alkyl group-containing group having a cyclic structure, and the like.
The tertiary alkyl group-containing group not having a cyclic structure is a group containing a branched tertiary alkyl group as the tertiary alkyl group and having no cyclic structure in the structure.
Examples of the branched tertiary alkyl group include groups represented by the following general formula (I).

In formula (I), R ^{21 to} R ²³ are each independently a linear or branched alkyl group. 1-5 are preferable and, as for carbon number of this alkyl group, 1-3 are more preferable.
Moreover, it is preferable that the total carbon number of group represented by general formula (I) is 4-7, it is more preferable that it is 4-6, and it is most preferable that it is 4-5.
Specific examples of the group represented by the general formula (I) include a tert-butyl group and a tert-pentyl group, and a tert-butyl group is more preferable.

Examples of the tertiary alkyl group-containing group that does not have a cyclic structure include the above-described branched tertiary alkyl group; the above-described branched tertiary alkyl group is a linear or branched alkylene group A tertiary alkyl group-containing chain alkyl group bonded to the above; a tertiary alkyloxycarbonyl group having the branched tertiary alkyl group described above as the tertiary alkyl group; And tertiary alkyloxycarbonylalkyl groups having a branched tertiary alkyl group.
The alkylene group in the tertiary alkyl group-containing chain alkyl group is preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and still more preferably an alkylene group having 1 to 2 carbon atoms. .
Examples of the chain-like tertiary alkyloxycarbonyl group include a group represented by the following general formula (II). ^R 21 ^{to R 23} in the formula (II) is the same as ^R 21 ^{to R 23} in general formula (I). The chain-like tertiary alkyloxycarbonyl group is preferably a tert-butyloxycarbonyl group (t-boc) or a tert-pentyloxycarbonyl group.
Examples of the chain-like tertiary alkyloxycarbonylalkyl group include a group represented by the following general formula (III). ^R 21 ^{to R 23} in the formula (III) are the same as ^R 21 ^{to R 23} in general formula (I). f is an integer of 1 to 3, and 1 or 2 is preferable. As the chain-like tertiary alkyloxycarbonylalkyl group, a tert-butyloxycarbonylmethyl group and a tert-butyloxycarbonylethyl group are preferable.
Of these, the tertiary alkyl group-containing group having no cyclic structure is preferably a tertiary alkyloxycarbonyl group or a tertiary alkyloxycarbonylalkyl group, more preferably a tertiary alkyloxycarbonyl group. Most preferred is a tert-butyloxycarbonyl group.

The tertiary alkyl group-containing group having a cyclic structure is a group having a tertiary carbon atom and a cyclic structure in the structure.
In the tertiary alkyl group-containing group having a cyclic structure, the cyclic structure preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and more preferably 6 to 10 carbon atoms constituting the ring. Most preferred. Examples of the cyclic structure include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Preferable 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 tertiary alkyl group-containing group having a cyclic structure include a group having the following group (1) or (2) as a tertiary alkyl group.
(1) A group in which a linear or branched alkyl group is bonded to a carbon atom constituting a ring of a cyclic alkyl group (cycloalkyl group), and the carbon atom is a tertiary carbon atom.
(2) A group in which an alkylene group having a tertiary carbon atom (branched alkylene group) is bonded to the carbon atom constituting the ring of the cycloalkyl group.

The linear or branched alkyl group in the group (1) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. .
Specific examples of the group (1) include 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 1-methyl-1-cycloalkyl group, 1-ethyl-1-cycloalkyl group and the like. Can be mentioned.

In the above (2), the cycloalkyl group to which the branched alkylene group is bonded may have a substituent. Examples of the substituent include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (═O), and the like.
Specific examples of the group (2) include groups represented by the following chemical formula (IV).

In the formula (IV), R ²⁴ is a cycloalkyl group which may or may not have a substituent. Examples of the substituent that the cycloalkyl group may have include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (═O).
R ²⁵ and R ²⁶ are each independently a linear or branched alkyl group, and examples of the alkyl group include the same alkyl groups as R ^{21 to} R ²³ in the formula (I). It is done.

Examples of the alkoxyalkyl group for Z include groups represented by the following general formula (V).
In the formula, R ⁴¹ is a linear, branched or cyclic alkyl group.
When R ⁴¹ 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 ⁴¹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
^R42 is a linear or branched alkylene group. The alkylene group preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and still more preferably 1 to 2 carbon atoms.
As the alkoxyalkyl group for Z, a group represented by the following general formula (VI) is particularly preferable.

In the formula (VI), R ⁴¹ is the same as described above, and R ⁴³ and R ⁴⁴ are each independently a linear or branched alkyl group or a hydrogen atom.
In R ⁴³ and R ⁴⁴ , 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, one of R ⁴³ and R ⁴⁴ is preferably a hydrogen atom and the other is a methyl group.

  Among these, as Z, a tertiary alkyl group-containing group is preferable, a tertiary alkyloxycarbonyl group is more preferable, a group represented by the general formula (II) is more preferable, and tert-butyloxycarbonyl The group (t-boc) is most preferred.

In the general formula (a0-1), a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b = 1 to 3.
a is preferably 1.
b is preferably 0.
a + b is preferably 1.
c is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.
d is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.
e is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.

  As the structural unit (a0), a structural unit represented by general formula (a0-2) shown below is particularly desirable.

［式中、Ｒ，Ｚ，ｂ，ｃ，ｄ，ｅは前記と同じである。］

[Wherein R, Z, b, c, d and e are the same as described above. ]

  The monomer for deriving the structural unit (a0) is, for example, a compound represented by the following general formula (a0′-1) (an acrylate ester containing an aliphatic cyclic group having 1 to 3 alcoholic hydroxyl groups). It can be synthesized by protecting some or all of the hydroxyl groups with Z using a known method.

［式中、Ｒ，Ｙ^１，ａ，ｂ，ｃ，ｄ，ｅは前記と同じである。］

[Wherein, R, Y ¹ , a, b, c, d, and e are the same as described above. ]

In the component (A), as the structural unit (a0), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a0) in the component (A) is preferably 5 to 90 mol%, and preferably 10 to 80 mol%, based on the total of all structural units constituting the component (A). More preferably, it is more preferably 20 to 75 mol%, and most preferably 30 to 65 mol%. When it is at least the lower limit, the solubility of the component (A) in the component (S) is improved, and when it is at most the upper limit, the balance with other structural units is good.

[Structural unit (a1)]
The structural unit (a1) is a structural unit derived from an acrylate ester having an acid dissociable, dissolution inhibiting group.
Here, in the present specification and claims, “acid dissociation” in an acid dissociable, dissolution inhibiting group means an acid contained in a resist film formed using a chemically amplified resist composition at the time of exposure. It means that it can be dissociated from the component (A) by the action of an acid generated from the generator component. The “dissolution-inhibiting group” is a group that has an alkali dissolution inhibiting property that makes the entire component (A) insoluble in alkali before dissociation and changes the entire component (A) to alkali-soluble after dissociation.
As the acid dissociable, dissolution inhibiting group in the structural unit (a1), those proposed so far as the acid dissociable, dissolution inhibiting group of the base resin for chemically amplified resist 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. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.

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

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

The “aliphatic cyclic group” in the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group indicates a monocyclic group or polycyclic group having no aromaticity.
The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like. The basic ring structure of the aliphatic cyclic group excluding substituents 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.
Specific examples of the aliphatic cyclic group include, for example, a monocycloalkane, bicycloalkane, tricycloalkane, which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group, Examples include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as tetracycloalkane. 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-2 -Adamantyl group, 2-ethyl-2-adamantyl group, etc. are mentioned. Alternatively, in a structural unit represented by the following general formula (a1 ″), an aliphatic cyclic group such as an adamantyl group, such as a group bonded to an oxygen atom of a carbonyloxy group (—C (O) —O—); And a group having a branched alkylene group having a tertiary carbon atom bonded thereto.

［式中、Ｒは上記と同じであり、Ｒ^１５、Ｒ^１６はアルキル基（直鎖、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 is the same as described above, and R ¹⁵ and R ¹⁶ represent an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms). ]

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

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

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

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

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

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

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

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

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

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

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group. It is particularly preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula, R ¹⁷ and R ¹⁹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon atoms), and the end of R ^{19 and} the end of R ¹⁷ And may be combined.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  As the structural unit (a1), 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, acetal type acid dissociable, dissolution inhibiting group and the like. .

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 4 carbon atoms or a divalent aliphatic cyclic group, and the aliphatic cyclic group is the above except that a group in which two or more hydrogen atoms are removed is used. The thing similar to description of an "aliphatic cyclic group" can be used.

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

［上記式中、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；ｍは０または１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。］

[In the above formula, 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; M represents 0 or 1; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. ]

In the R ¹ ′ and R ² ′, at least one is preferably a hydrogen atom, and more preferably both are hydrogen atoms. n is preferably 0 or 1.

X ′ is the same as the tertiary alkyl ester type acid dissociable, dissolution inhibiting group exemplified in X ¹ above.
Examples of the aliphatic cyclic group for Y include the same groups as those exemplified above in the description of “aliphatic cyclic group”.

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

Among the above, the structural unit represented by the general formula (a1-1) is preferable, and specifically, (a1-1-1) to (a1-1-6) or (a1-1-35) to (a1). It is more preferable to use at least one selected from structural units represented by -1-41).
Furthermore, as the structural unit (a1), in particular, those represented by the following general formula (a1-1-01) including the structural units of the formulas (a1-1-1) to (a1-1-4) The following general formula (a1-1-02) including the structural units of formulas (a1-1-35) to (a1-1-41) is also preferable.

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

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

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

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

In general formula (a1-1-01), R is the same as defined above.
The lower alkyl group for R ^{11 is the same as} the lower alkyl group for R ¹¹ . In consideration of solubility in the component (S), a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.

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.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
In the component (A), the proportion of the structural unit (a1) is preferably from 5 to 90 mol%, more preferably from 10 to 80 mol%, more preferably from 15 to 75 mol%, based on all structural units constituting the component (A). Is more preferable, and it is most preferable that it is 20-65 mol%. If it is above the lower limit, it occurs in the resist film coated with the coating film at the exposed portion of the resist coating film and diffuses into the resist coating film when exposure is performed during resist pattern formation. By the action of the acid thus produced, the alkali solubility of the exposed portion is sufficiently increased. Therefore, by developing, a resist pattern is formed on the lower resist film, and at the same time, a pattern having excellent followability to the resist pattern is formed on the resist coating film. Moreover, the balance with another structural unit becomes favorable by setting it as below an upper limit.

  In the case where the structural unit (a0) includes an acid dissociable, dissolution inhibiting group, the structural unit (a0) also corresponds to the structural unit (a1). Is included in the structural unit (a0) and not included in the structural unit (a1). That is, the structural unit (a1) does not include the structural unit represented by the general formula (a0-1).

[Structural unit (a2)]
In addition to the structural unit (a0) and the structural unit (a1), the component (A) may further have a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group. By adjusting the proportion of the structural unit (a2) in the component (A), the dynamic contact angle and static contact angle on the resist coating film surface can be adjusted.
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.

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, and m is an integer of 0 or 1] And 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).
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.
In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.
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 general formulas (a2-1) to (a2-5), and at least one selected from general formulas (a2-1) to (a2-3). It is preferable to use more than one species. Specifically, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-3-1), (a2-3) -2), at least one selected from (a2-3-9) and (a2-3-10) is preferably used.

In the component (A), as the structural unit (a2), one type of structural unit may be used alone, or two or more types may be used in combination.
When the structural unit (a2) is contained in the component (A), the proportion of the structural unit (a2) in the component (A) is from 1 to the total of all structural units constituting the component (A). 60 mol% is preferable, 10-50 mol% is more preferable, 15-40 mol% is further more preferable, and it is most preferable that it is 15-30 mol%. 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)]
In addition to the structural units (a0) and (a1) or in addition to the structural units (a0), (a1) and (a2), the component (A) is an acrylic further containing a polar group-containing aliphatic hydrocarbon group You may have the structural unit (a3) induced | guided | derived from an acid ester. The structural unit (a3) contributes to improving the resolution by, for example, increasing the hydrophilicity of the entire component (A), increasing the affinity with the developer, and improving the alkali solubility in the exposed area. In particular, when an alcohol solvent is used as the component (S1), it is preferable to include the structural unit (a3) because the solubility of the component (A) in the component (S) is improved.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a polycyclic aliphatic hydrocarbon group (polycyclic group). . 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 one or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, or the like. Specific examples include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

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

（式中、Ｒは前記に同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。）

(Wherein R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t 'is an integer of 1 to 3, and l is an integer of 1 to 5) And s is an integer of 1 to 3.)

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

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
When the structural unit (a3) is contained in the component (A), the proportion of the structural unit (a3) in the component (A) is 1 to 50 mol relative to all the structural units constituting the component (A). %, Preferably 5 to 40 mol%, more preferably 10 to 25 mol%. The effect by including a structural unit (a3) is fully acquired by setting it as more than a lower limit. By setting it to the upper limit value or less, it is possible to balance with other structural units, and the resist coating film to be obtained has high hydrophobicity and is suitable for immersion exposure.

In the structural unit (a0), when the aliphatic cyclic group of Y ¹ in the general formula (a0-1) is a hydrocarbon group and b is 1 or 2, the structural unit (a0) is Although it corresponds to the structural unit (a3) in that it is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group, in the present invention, the structural unit is a structural unit ( It is included in a0) and not included in the structural unit (a3). That is, the structural unit (a3) does not include the structural unit represented by the general formula (a0-1).

[Other structural units]
The component (A) may contain a structural unit (a4) other than the structural units (a0), (a1), (a2), and (a3) as long as the effects of the present invention are not impaired.
The structural unit (a4) is not particularly limited as long as it is another structural unit that is not classified into the above structural units (a0), (a1), (a2), and (a3). For ArF excimer laser, A number of hitherto known materials can be used for resist resins such as for excimer lasers (preferably for ArF excimer lasers).
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group is preferable. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the resin component of the resist composition.
In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, a tetracyclododecanyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

（式中、Ｒは前記と同じである。）

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

As the structural unit (a4), one type may be used alone, or two or more types may be used in combination.
When the structural unit (a4) is contained in the component (A), the proportion of the structural unit (a4) in the component (A) is from 1 to the total of all structural units constituting the component (A). It is preferably 30 mol%, more preferably 10 to 20 mol%.

  In the present invention, the component (A) is preferably a copolymer having at least the structural units (a0) and (a1). Examples of the copolymer include a binary copolymer composed of the structural units (a0) and (a1), a ternary copolymer composed of the structural units (a0), (a1), and (a2), Examples thereof include terpolymers composed of the structural units (a0), (a1) and (a3), quaternary copolymers composed of the structural units (a0), (a1), (a2) and (a3). . In particular, when a chain ether solvent such as diisopentyl ether is used as the component (S1), the binary copolymer is preferable. Further, when an alcohol solvent is used as the component (S1), a copolymer containing the structural unit (a3) is preferable.

Specific examples of the binary copolymer include a copolymer represented by the following general formula (A-21), a copolymer represented by the following general formula (A-22), and the following general formula ( And a copolymer represented by A-23).
Specific examples of the ternary copolymer include, for example, a copolymer represented by the following general formula (A-31), a copolymer represented by the following general formula (A-32), and the following general formula ( And a copolymer represented by A-33).
Specific examples of the quaternary copolymer include a copolymer represented by the following general formula (A-41).

［式中、Ｒ、Ｒ^２１〜Ｒ^２３およびｅは前記と同様であり、Ｒ^２７およびＲ^２８はそれぞれ独立して低級アルキル基であり、ｎ_２９は０〜３の整数である。］

[Wherein, R, R ^{21 to} R ²³ and e are the same as defined above, R ²⁷ and R ²⁸ each independently represent a lower alkyl group, and n ₂₉ represents an integer of 0 to 3. ]

［式中、Ｒ、Ｒ^２１〜Ｒ^２３、Ｒ^２７、Ｒ^２８およびｅは前記と同様である。］

[Wherein, R, R ^{21 to} R ²³ , R ²⁷ , R ²⁸ and e are the same as defined above. ]

［式中、Ｒ、Ｒ^２１〜Ｒ^２３、Ｒ^２７、ｅは前記と同様である。］

[Wherein, R, R ^{21 to} R ²³ , R ²⁷ and e are the same as defined above. ]

In the above formulas (A-21), (A-31) and (A-32), examples of the lower alkyl group for R ²⁷ include the same lower alkyl groups as those for R. R ²⁷ is preferably a methyl group or an ethyl group.
In the above formulas (A-22) and (A-33), examples of the lower alkyl group for R ²⁸ include the same as the lower alkyl group for R. R ²⁸ is preferably a methyl group or an ethyl group, and particularly preferably an ethyl group.
In the above formula (A-23), n29 is preferably 0 or 1, and 0 is particularly preferable.
These copolymers may be used individually by 1 type, and may use 2 or more types together.

The component (A) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). In addition, the component (A) is used in combination with a chain transfer agent such as, for example, HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH at the time of the polymerization. A —C (CF ₃ ) ₂ —OH group may be introduced into the.

The weight average molecular weight (Mw) of the component (A) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and most preferably 4000 to 10000. preferable. When the content is smaller than the upper limit of this range, the solubility in the component (S) is high. It is.
The degree of dispersion (Mw / number average molecular weight (Mn)) is not particularly limited, but is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and 1.2 to 2. 5 is most preferred. In addition, Mn shows a number average molecular weight.

The component (A) used in the present invention is soluble in the component (S). Whether the resin to be used can be dissolved in the component (S) is determined by, for example, mixing the resin and the component (S) so that the resin concentration becomes 1% by mass under the condition of 23 ° C. It can be judged by whether or not a transparent solution is obtained when ultrasonic waves are applied.
As the component (A) that is preferably used in the present invention, those having a solubility capable of obtaining a transparent solution within 0 to 30 minutes under the above conditions are preferable.
The solubility of the component (A) in the component (S) varies depending on the type of the component (S1) to be used, but the type and ratio of the structural unit constituting the component (A), the mass average molecular weight, etc. are adjusted. Can be adjusted. For example, in the component (A), the higher the proportion of the structural unit (a1) described later, the better the solubility in the component (S).

<(S) component>
In the present invention, the component (S) is at least one organic solvent (S1) selected from the group consisting of an ether-based organic solvent having no hydroxyl group and an alcohol-based solvent (hereinafter referred to as component (S1)). contains. By containing the component (S1), the resist coating film can be formed without damaging the resist film when the resist coating film forming material of the present invention is applied onto the resist film.

Here, the “ether organic solvent” is a compound that has an ether bond (C—O—C) in its structure and is liquid at normal temperature and pressure.
The boiling point (under normal pressure) of the ether organic solvent is preferably 30 to 300 ° C, more preferably 100 to 200 ° C, and further preferably 140 to 180 ° C. By being above the lower limit value of the temperature range, by setting the boiling point within the above range, the component (S) is sufficiently removed from the coating film by baking, and the formability of the resist coating film is improved.

As an ether organic solvent having no hydroxyl group, the resist film is difficult to dissolve when a resist coating film forming material is applied onto the resist film, and the effects of the present invention are excellent. The compound (s1-1) represented by -1) is preferable.
R ⁶⁰ —O—R ⁶¹ (s1-1)
[Wherein, R ⁶⁰ and R ⁶¹ each independently represent a monovalent hydrocarbon group. Alternatively, each of R ⁶⁰ and R ^{61 is a} divalent hydrocarbon group, and R ⁶⁰ and R ⁶¹ may be bonded to form a ring. ]

In the above formula, examples of the monovalent hydrocarbon group of R ⁶⁰ and R ⁶¹ include an alkyl group and an aryl group, and an alkyl group is preferable. Among ^them, it is preferable that any of R ^{60, R 61} is an alkyl ^group, more preferably a ^{R 60} and ^{R 61} are the same alkyl group.
As each of the alkyl groups of R ^60, R ^61, not particularly limited, for example, straight, branched or cyclic alkyl group, and the like. In the alkyl group, part or all of the hydrogen atoms may or may not be substituted with a halogen atom or the like.
The alkyl group preferably has 1 to 15 carbon atoms, and more preferably 1 to 10 carbon atoms because the applicability of the resist coating film forming material is good. Specific examples include an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a cyclopentyl group, and a hexyl group, and an n-butyl group and an isopentyl group are particularly preferable. .
The halogen atom that may be substituted for the hydrogen atom of the alkyl group is preferably a fluorine atom.

Each aryl group for R ⁶⁰ and R ⁶¹ is not particularly limited, and is, for example, an aryl group having 6 to 12 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 halogen atom 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. Specifically, a phenyl group, a benzyl group, a naphthyl group, etc. are mentioned, for example.
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 more preferable.
As the alkoxy group which may substitute the hydrogen atom of the said aryl group, a C1-C5 alkoxy group is preferable and a methoxy group and an ethoxy group are more preferable.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.

In the above formula, each of R ⁶⁰ and R ⁶¹ is a divalent hydrocarbon group, and R ⁶⁰ and R ⁶¹ may be bonded to form a ring.
Examples of the divalent hydrocarbon group include a group obtained by removing one hydrogen atom from the alkyl group or aryl group, that is, an alkylene group or an arylene group, and an alkylene group is particularly preferable. In the alkylene group or arylene group, a part of carbon atoms may be substituted with an oxygen atom.
R ⁶⁰ and R ⁶¹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 10 carbon atoms), and the end of R ^{60 and} the end of R ⁶¹ are bonded to each other. To form a ring.

  Specific examples of the ether compound (s1-1) include 1,8-cineol (boiling point 176 ° C.), dibutyl ether (boiling point 142 ° C.), diisopentyl ether (diisoamyl ether) (boiling point 171 ° C.), dioxane ( Boiling point 101 ° C.), anisole (bp 155 ° C.), ethyl benzyl ether (bp 189 ° C.), diphenyl ether (bp 259 ° C.), dibenzyl ether (bp 297 ° C.), phenetole (bp 170 ° C.), butyl phenyl ether, tetrahydrofuran ( Boiling point 66 ° C), ethyl propyl ether (boiling point 63 ° C), diisopropyl ether (boiling point 69 ° C), dihexyl ether (boiling point 226 ° C), dipropyl ether (boiling point 91 ° C), and the like.

  In the present invention, the ether-based organic solvent having no hydroxyl group is preferably a cyclic or chain ether-based organic solvent because it is excellent in the effects of the present invention. Among them, diisopentyl ether and / or 1,8- Preferably it contains cineol.

An “alcohol-based organic solvent” is a compound in which at least one hydrogen atom of an aliphatic hydrocarbon is substituted with a hydroxyl group, and is a compound that is liquid at normal temperature and normal pressure.
The boiling point of the alcohol-based organic solvent is preferably 80 to 160 ° C, more preferably 90 to 150 ° C, and most preferably 100 to 135 ° C from the viewpoint of applicability. Here, the monohydric alcohol means a case where the number of hydroxyl groups contained in the alcohol molecule is one, and a polyhydric alcohol and its derivatives (for example, a hydrogen atom of some hydroxyl groups is a substituent such as an alkyl group). Is not included).

In the present invention, the alcohol-based organic solvent preferably contains at least one selected from the group consisting of alcohols having 4 to 6 carbon atoms. Such an alcohol has a low compatibility with the resist film, and is therefore excellent in the effect of the present invention. Moreover, it is preferable also at points, such as being excellent in the solubility of (A) component, and high safety | security with respect to an environment.
As the alcohol having 4 to 6 carbon atoms, a monohydric alcohol is more preferable, and among them, a primary monohydric alcohol is most preferable.
Specific examples of the alcohol having 4 to 6 carbon atoms include n-pentanol (boiling point 138.0 ° C.), s-pentanol (boiling point 119.3 ° C.), t-pentanol (101.8 ° C.), isopentane Tanol (boiling point 130.8 ° C), isobutanol (boiling point 107.9 ° C), 2-ethylbutanol (boiling point 147 ° C), neopentanol (boiling point 114 ° C), n-butanol (boiling point 117.7 ° C), s -Butanol (boiling point 99.5 ° C), t-butanol (boiling point 82.5 ° C), n-hexanol (boiling point 157.1 ° C), 2-methyl-1-butanol (boiling point 128.0 ° C), 2-methyl -2-butanol (boiling point 112.0 ° C.), 4-methyl-2-pentanol (boiling point 131.8 ° C.) and the like.
In the present invention, particularly, the alcohol organic solvent is at least one selected from the group consisting of isobutanol (2-methyl-1-propanol), 4-methyl-2-pentanol and n-butanol. Is preferable, and isobutanol is particularly preferable.

(S1) A component may be used individually by 1 type and may use 2 or more types.
In the present invention, the component (S1) is preferably at least one selected from the group consisting of a cyclic or chain ether-based organic solvent having no hydroxyl group and an alcohol-based solvent, and in particular, diisopentyl ether. , 1,8-cineol and isobutanol are preferable.
In the component (S), the proportion of the component (S1) is preferably 50 to 100% by mass, preferably 75 to 100% by mass, and 90 to 100% of the total mass of the component (S) for the effect of the present invention. % By mass is more preferable, and 100% by mass is most preferable.

The component (S) may contain an organic solvent other than the component (S1) (hereinafter referred to as the component (S2)) as long as the effects of the present invention are not impaired. By using the component (S2) in combination, the solubility and other characteristics of the component (A) can be adjusted.
As the component (S2), for example, one or two or more arbitrary types that do not correspond to the component (S1) can be appropriately selected from conventionally known solvents for chemically amplified resists. The component (S2) is the same as the organic solvent (S ′) mentioned in the chemically amplified resist composition described in the resist pattern forming method described later (except for the component (S1)). .

The amount of component (S) used is not particularly limited as long as the concentration of component (A) is such that the resist coating film-forming material can be applied onto the resist film. It is set appropriately according to the coating film thickness.
The concentration of the component (A) in the resist coating film forming material is preferably in the range of 0.1 to 2% by mass, and more preferably 0.2 to 1% by mass.

<Optional component>
The resist coating film forming material of the present invention may contain components other than the component (A) and the component (S) as long as the effects of the present invention are not impaired. Examples of the other components include components generally blended in resist compositions, and specific examples include components ((A ′) listed in “Chemically Amplified Resist Composition” described later. Component, (B ′) component, (D ′) component, (E ′) component, etc.).
When the resist coating film forming material of the present invention is used for immersion exposure, in order to prevent elution of substances into the immersion medium, the (B ′) component, the (D ′) component, (E ′ ) It is preferable not to contain a low molecular weight compound such as a component.

The material for forming a resist coating film of the present invention is used for forming a coating film on a resist film formed using a chemically amplified resist composition, and the resist coating film of the present invention According to the forming material, the resist coating film can be formed on the resist film without impairing the lithography characteristics. Therefore, according to the resist coating film forming material of the present invention, a resist pattern having an excellent shape can be formed. For example, the verticality of the pattern side wall is high, and the roughness (surface roughness) of the surface is small. A resist pattern having a highly rectangular cross-sectional shape can be formed.
In addition, since the conventional resist coating film uses a resin that is completely different from the resin used for the resist film as described above, there is a problem that defects are likely to occur. The resist film and the resist coating film can be formed using the same acrylic resin. Therefore, defects can be reduced.

Further, the resist coating film formed using the resist coating film forming material of the present invention can remove the exposed portion together with the underlying resist film by development when forming a resist pattern. That is, the resist coating film can be patterned simultaneously with the resist film. Therefore, it is not necessary to provide a separate step for removing the resist coating film, and the resist pattern can be easily formed.
That is, the resist coating film formed on the resist film using the resist coating film forming material of the present invention is alkali-insoluble before exposure. When the resist film is selectively exposed through the resist coating film, an acid is generated from the “acid generator component that generates an acid by exposure” in the resist film of the exposed portion. The acid increases the alkali solubility of the resist film (positive type), and at the same time, part of the acid moves to the resist coating film on the resist film and acts on the component (A) to make the alkali soluble. Increase. Therefore, when selective exposure is performed in the formation of the resist pattern, the resist film and the resist coating film in the exposed portion turn into alkali-soluble, while the resist film and the resist coating film in the unexposed portion remain insoluble in alkali. Therefore, by performing alkali development, the resist coating film and the resist film in the exposed portion are removed, and a resist pattern is formed.
Further, since the resist coating film in the unexposed portion remains without being removed, the etching resistance of the resist pattern is improved as compared with the case where the resist coating film is not provided.

Furthermore, the resist coating film formed using the resist coating film forming material of the present invention can easily improve the surface hydrophobicity by selecting the type of the constituent unit of the component (A). . In addition, since it does not have to contain low molecular weight components (component (B ′), component (D), component (E), etc., which will be described later) contained in a normal chemically amplified resist composition, Substance elution from the resist film during exposure can be effectively suppressed. Therefore, the resist coating film forming material of the present invention is suitably used in immersion exposure applications.
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 of substances in the resist film (components (B ′) and (D ′) described later) into the immersion solvent (substance elution) Occurs. Substance elution causes phenomena such as alteration of the resist layer and change in the refractive index of the immersion solvent, thereby deteriorating the lithography properties. 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 conventional chemically amplified resist composition has an influence on the lithography properties, and thus it is difficult to increase the hydrophobicity. However, the material for forming a resist coating film of the present invention can easily increase the hydrophobicity. Therefore, the hydrophobicity of the resist coating film surface to be formed is increased, and the contact angle with water, for example, the static contact angle (the angle formed between the water droplet surface on the horizontal resist film and the resist film surface), the dynamic contact angle (Contact angle when water drops begin to fall when the resist film is tilted. Contact angle (advance angle) at the front end point of the water drop direction and contact angle (retreat angle) at the end point behind the drop direction) ), And the falling angle (the inclination angle of the resist film when the water droplet starts to fall when the resist film is inclined) can be easily changed. For example, the higher the surface hydrophobicity, the larger the static and dynamic contact angles, 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 inclined, the advance angle starts to move (drop) on the plane 2 when the droplet 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 moving (falling) on the plane 2), the angle θ2 formed by the droplet surface at the upper end 1b of the droplet 1 and the plane ₂ is the receding angle, The inclination angle θ _{3 of the} plane 2 is the falling angle.

The static contact angle, dynamic contact angle, and sliding angle can be measured, for example, as follows.
First, a resist composition solution is spin-coated on a silicon substrate, and then heated for 90 seconds under a predetermined condition, for example, a temperature condition of 110 to 115 ° C., to form a resist film.
Next, DROP MASTER-700 (manufactured by Kyowa Interface Science Co., Ltd.), AUTO SLIDING ANGLE: SA-30DM (manufactured by Kyowa Interface Science Co., Ltd.), AUTO DISPENSER: AD-31 (manufactured by Kyowa Interface Science Co., Ltd.) It can measure using commercially available measuring apparatuses, such as.

The resist coating film forming material of the present invention preferably has a measured value of the receding angle on the resist coating film surface formed using the resist coating film forming material of 60 degrees (°) or more, It is more preferably 60 to 150 °, particularly preferably 70 to 130 °, and most preferably 70 to 100 °. When the receding angle is 60 ° or more, the resist film surface is excellent in hydrophobicity and the substance elution suppression effect is improved, and when the receding angle is 150 ° or less, the lithography characteristics and the like are good.
For the same reason, the measured value of the static contact angle on the resist coating film surface is preferably 75 ° or more, more preferably 75 to 100 °, and more preferably 80 to 95 °. Particularly preferred.

  The size of the above-mentioned static contact angle, receding angle, etc. is determined by the composition of the resist coating film forming material, for example, the type of the component (A), the structural unit (component (a0), (a1) in the component (A) ), (A2), (a3), etc.), etc. For example, the use of a compound having a polycyclic group as the acid dissociable, dissolution inhibiting group in the structural unit (a1) in the component (A) increases the hydrophobicity of the resulting resist coating film, resulting in a static contact angle or receding angle. Becomes larger. Moreover, when the thing which has a monocyclic group is used as an acid dissociable, dissolution inhibiting group in a structural unit (a1), compared with the case where the thing which has a polycyclic group is used, hydrophobicity will fall.

As described above, according to the resist coating film forming material of the present invention, substance elution into the immersion solvent is suppressed. Therefore, by using the resist coating film forming material of the present invention in immersion exposure, it is possible to suppress the alteration of the resist film and the change in the refractive index of the immersion solvent. Therefore, 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. Although followability is required, the resist coating film formed from the resist coating film forming material has high hydrophobicity and high water following ability.
Thus, according to the resist coating film forming material of the present invention, characteristics (hydrophobicity, suppression of substance elution) required in immersion exposure without impairing lithography characteristics (sensitivity, resolution, etching resistance, etc.) Performance, water followability, etc.). Therefore, the resist coating film forming material is suitable for immersion exposure.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention includes a step of forming a resist film using a chemically amplified resist composition on a support, and a resist coating material using the resist coating film forming material of the present invention on the resist film. It includes a step of forming a coating film to obtain a resist laminate, a step of exposing the resist laminate, and a step of developing the resist laminate to form a resist pattern.

The resist pattern forming method in the present invention can be performed, for example, as follows.
First, a resist film is formed on a support using a chemically amplified resist composition.
The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).

The resist film can be formed by a conventionally known method. Specifically, for example, a chemically amplified resist composition is applied onto a support with a spinner or the like, and baked at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 90 seconds (pre-baking (post-apply baking). (PAB))) can be applied to form a resist film.
The thickness of the resist film is not particularly limited. Considering resolution, etching resistance and the like, it is preferably in the range of 30 to 400 nm, more preferably 50 to 300 nm.

  In the present invention, a positive type resist composition is used as the chemically amplified resist composition. Although the positive chemically amplified resist composition will be described in detail later, generally, a resin component whose alkali solubility is increased by the action of an acid and an acid generator component which generates an acid upon irradiation (exposure) of radiation. Containing. A resist film formed using such a resist composition is alkali-insoluble before exposure. When selective exposure is performed during resist pattern formation, an acid is generated from the acid generator component, and the acid is an alkali of the resin component. Increase solubility. As a result, the exposed portion of the resist film turns to alkali-soluble, while the unexposed portion remains insoluble in alkali and does not change, so that the exposed portion is dissolved and removed by alkali development to form a resist pattern.

Next, a resist coating film is formed on the resist film using the resist coating film forming material of the present invention to obtain a resist laminate.
The resist coating film can be formed by the same method as that for forming the resist film. Specifically, for example, a resist coating film forming material is applied onto the resist film with a spinner or the like, and subjected to a baking treatment at a temperature of 60 to 120 ° C. for 40 to 120 seconds, preferably 60 to 90 seconds. A coating film can be formed.
The thickness of the resist coating film is preferably 1 nm or more in consideration of the effect of providing the resist coating film, for example, improvement of surface hydrophobicity, suppression of substance elution during immersion exposure, improvement of etching resistance, etc. 5 nm or more is more preferable.
The upper limit of the thickness is not particularly limited, but is preferably 40 nm or less, more preferably 30 nm or less, and further preferably 25 nm or less. When the thickness is 40 nm or less, the above-described effects can be sufficiently obtained, and the resist coating film can be easily formed. For example, even when the resist coating film forming material does not contain an acid generator component, the acid generated in the lower resist film by exposure during the resist pattern formation sufficiently diffuses into the resist coating film. The alkali solubility of the resist coating film in the exposed area is sufficiently increased by the action of the acid. Therefore, by developing, a resist pattern is formed on the lower resist film, and at the same time, a pattern having excellent followability to the resist pattern is formed on the resist coating film. Therefore, a resist pattern having excellent lithography properties such as shape and resolution can be obtained.
The thickness of the resist coating film can be adjusted by adjusting the concentration of the component (A) in the resist coating film forming material, application conditions, and the like. For example, the lower the concentration of the component (A), the thinner the film thickness. The coating film is formed.

Next, the resist laminate is selectively exposed using a predetermined exposure light source with or without a desired mask pattern. That is, exposure is performed through the mask pattern, or drawing is performed by direct irradiation with an electron beam without using the mask pattern.
The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation. The present invention is particularly effective for ArF excimer lasers.

At this time, the selective exposure of the resist laminate may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be performed by immersion exposure.
The resist coating film formed from the resist coating film forming material of the present invention has higher hydrophobicity than a resist film formed using a general chemical amplification resist composition, Since it is excellent in the effect of suppressing substance elution, it is particularly suitable for immersion exposure.
As described above, in the immersion exposure, at the time of exposure, a portion between the lens and the resist laminate, which is conventionally filled with an inert gas such as air or nitrogen, has a refractive index larger than the refractive index of air. It can implement by exposing in the state satisfy | filled with the solvent (immersion medium) which has.
More specifically, in the immersion exposure, a solvent (immersion medium) having a refractive index larger than the refractive index of air is formed between the resist laminate obtained as described above and the lens at the lowest position of the exposure apparatus. ), And in that state, exposure (immersion exposure) can be performed through a desired mask pattern.

As the immersion medium, a solvent having a refractive index larger than that of air and smaller than that of the resist coating film and the resist film 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 that of air and smaller than that of the resist coating film and the resist film include water, fluorine-based inert liquid, silicon-based solvent, hydrocarbon-based solvent, and the like. Can be mentioned.
Specific examples of the fluorine-based inert liquid include fluorine-based 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.).
Since the resist coating film formed by using the resist coating film forming material is not particularly adversely affected by water, water is preferably used as a solvent having a refractive index larger than that of air. Water is also preferable from the viewpoints of cost, safety, environmental problems, and versatility.

  After the selective exposure, baking (post-exposure baking (PEB)) is preferably performed at 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 90 seconds. By performing PEB, acid diffusion in the resist film, dissociation of the acid dissociable, dissolution inhibiting group in the resist film, and the like are promoted, and a resist pattern can be formed with high sensitivity. Further, by promoting the diffusion of the acid in the resist film, the diffusion of the acid into the resist coating film is also promoted. Therefore, for example, even if the resist coating film forming material does not contain an acid generator component, the acid generated in the lower resist film by exposure sufficiently diffuses into the resist coating film, and the resist coating of the exposed portion Sufficiently increase the alkali solubility of the membrane.

  Next, the resist laminate is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), and preferably rinsed with pure water. The water rinsing can be performed, for example, by dropping or spraying water on the substrate surface while rotating the substrate to wash away the developer on the substrate and the resist composition for immersion exposure dissolved by the developer. And a resist pattern can be formed by drying.

<Chemically amplified resist composition>
The chemically amplified resist composition used in the present invention is a positive chemically amplified resist composition. Such a resist composition usually has a resin component (A ′) having an acid dissociable, dissolution inhibiting group and increased alkali solubility by the action of an acid (hereinafter referred to as component (A ′)), and radiation. What contains the acid generator component (B ') (henceforth (B') component) which generate | occur | produces an acid by irradiation (exposure) is used.
In such a resist composition, the component (A ′) is an alkali-insoluble one having a so-called acid dissociable, dissolution inhibiting group. When an acid is generated from the component (B ′) by exposure during the formation of the resist pattern, the acid By dissociating the acid dissociable, dissolution inhibiting group, the component (A ′) becomes alkali-soluble. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the resist composition on the substrate is selectively exposed, the exposed part turns to alkali-soluble while the unexposed part remains alkali-insoluble. Since it does not change, a resist pattern is formed by alkali development.

  As the component (A ′), a resin that is generally used as a base resin of a chemically amplified resist composition can be used, and those used for lithography using an ArF excimer laser are particularly preferable. As such a base resin, a resin having the structural unit (a1) as an essential structural unit, that is, an acrylic resin having an acid dissociable, dissolution inhibiting group is usually used. The acrylic resin may optionally further include one or more selected from the group consisting of the structural units (a2) to (a4). In particular, the structural units (a2) and (a3) may include It is preferable to have. In the present invention, in addition to these structural units, a resin having the structural unit (a0) is also preferably used.

  The component (B ′) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, 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 an acid generator represented by the following general formula (b-0).

［式中、Ｒ^５１は、直鎖、分岐鎖若しくは環状のアルキル基、または直鎖、分岐鎖若しくは環状のフッ素化アルキル基を表し；Ｒ^５２は、水素原子、水酸基、ハロゲン原子、直鎖若しくは分岐鎖状のアルキル基、直鎖若しくは分岐鎖状のハロゲン化アルキル基、または直鎖若しくは分岐鎖状のアルコキシ基であり；Ｒ^５３は置換基を有していてもよいアリール基であり；ｕ”は１〜３の整数である。］

[Wherein, R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic fluorinated alkyl group; R ⁵² represents a hydrogen atom, a hydroxyl group, a halogen atom, linear or A branched alkyl group, a linear or branched halogenated alkyl group, or a linear or branched alkoxy group; R ⁵³ is an aryl group which may have a substituent; u "Is an integer from 1 to 3.]

In the general formula (b-0), R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic 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 preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
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%. Those in which all hydrogen atoms are substituted with fluorine atoms are preferred because the strength of the acid is increased.
R ⁵¹ is most preferably a linear alkyl group or a fluorinated alkyl group.

R ⁵² is a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group, a linear or branched alkyl halide group, or a linear or branched alkoxy group.
In R ⁵² , examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom, and a fluorine atom is preferable.
In R ⁵² , the alkyl group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
In R ⁵² , the halogenated alkyl group is a group in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms. Examples of the alkyl group herein are the same as the “alkyl group” in R ⁵² . Examples of the halogen atom to be substituted include the same as those described above for the “halogen atom”. In the halogenated alkyl group, it is desirable that 50 to 100% of the total number of hydrogen atoms are substituted with halogen atoms, and it is more preferable that all are substituted.
In R ⁵² , the alkoxy group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
Among these, R ⁵² is preferably a hydrogen atom.

R ⁵³ is an aryl group which may have a substituent, and examples of the structure of the basic ring (matrix ring) excluding the substituent include a naphthyl group, a phenyl group, an anthryl group, and the like. From the viewpoint of absorption of exposure light such as ArF excimer laser, a phenyl group is desirable.
Examples of the substituent include a hydroxyl group and a lower alkyl group (straight or branched chain, preferably having 5 or less carbon atoms, particularly preferably a methyl group).
As the aryl group for R ^53, an aryl group having no substituent is more preferable.
u ″ is an integer of 1 to 3, preferably 2 or 3, and particularly preferably 3.

  Preferable examples of the acid generator represented by the general formula (b-0) include the following.

  Moreover, as an onium salt type acid generator other than the acid generator represented by general formula (b-0), the compound represented by the following general formula (b-1) or (b-2) is mentioned, for example.

［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；Ｒ^４”は、直鎖、分岐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; R ⁴ ″ represents a linear, branched or cyclic alkyl group or fluorinated group. Represents an alkyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. 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 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 be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, a straight, include alkyl groups such as branched or cyclic. 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.

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

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

  Specific examples of the onium salt acid generators represented by 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 trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate. 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, Preferably it is C3.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably It is C1-C7, More preferably, it is C1-C3.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

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

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

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

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

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

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

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

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

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

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

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

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, and most preferably a partially fluorinated alkyl group.
The fluorinated alkyl group in R ³⁵ preferably has 50% or more of the hydrogen atom of the alkyl group fluorinated, more preferably 70% or more, and even more preferably 90% or more. This is preferable because the strength of the acid is increased. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

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

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

  Of the above exemplified compounds, the following four compounds are preferred.

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

(B ') As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
Content of (B ') component in a resist composition 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.

In order to improve the resist pattern shape, the stability over time, etc., the resist composition is further mixed with a nitrogen-containing organic compound (D ′) (hereinafter referred to as (D ′) component) as an optional component. Can do.
Since a wide variety of components (D ′) have already been proposed, any known one can be used. Among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines, can be used. Is preferred. 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. The “aliphatic cyclic group” means a monocyclic group or polycyclic group having no aromaticity. 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-hexylamine, tri-n-pentylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, etc .; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more 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.
These may be used alone or in combination of two or more.
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 ′).

The resist composition is selected from the group consisting of organic carboxylic acids, phosphorus oxoacids and derivatives thereof as optional components for the purpose of preventing sensitivity deterioration, improving the resist pattern shape, stability over time, etc. At least one compound (E ′) (hereinafter referred to as component (E ′)).
Examples of the organic carboxylic acid include acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid. Among these, salicylic acid is preferable.
Examples of phosphorus oxo acids and derivatives thereof include phosphoric acid, phosphonic acid, phosphinic acid and the like, and among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of the phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
As the component (E ′), one type may be used alone, or two or more types may be used in combination.
The component (E ′) is used in a proportion of 0.01 to 5.0 parts by mass per 100 parts by mass of the component (A ′).

  The resist composition may further contain miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, dissolution inhibitors, plasticizers, stabilizers. Further, a colorant, an antihalation agent, a dye and the like can be added and contained as appropriate.

The resist composition can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as the (S ′) component).
As the component (S ′), any component can be used as long as it can dissolve each component to be used to form a uniform solution, and any one of conventionally known solvents for chemically amplified resists can be used. Or it can select and use 2 or more types suitably.
For example, lactones such as γ-butyrolactone;
Ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone;
Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol;
Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate or dipropylene glycol monoacetate, monomethyl ether, monoethyl ether, monopropyl of the polyhydric alcohols or the compound having an ester bond Derivatives of polyhydric alcohols such as ethers, monoalkyl ethers such as monobutyl ether or compounds having an ether bond such as monophenyl ether [in these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) Is preferred];
Cyclic ethers such as dioxane and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate;
Aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. be able to.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S ′), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
The amount of the component (S ′) used is not particularly limited, but is a concentration that can be applied to a substrate or the like and is appropriately set according to the coating film thickness. Generally, the solid content concentration of the resist composition is It is used in a range of 2 to 20% by mass, preferably 5 to 15% by mass.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
(A-01) to (A-07) and (A ′)-1 to (A ′)-2 used in Test Example 1 and Examples 1 to 9 below are monomers (1) to (6) shown below. ) Was synthesized by copolymerization using a known dropping polymerization method. The production method of the monomer (1) is shown in Synthesis Example 1 below.

<Synthesis Example 1: Synthesis of monomer (1)>
150 mL of THF (tetrahydrofuran) was placed in an eggplant flask, and 20 g of the above monomer (6) [1- (3-hydroxyladamantane methacrylate)] and 10 g of triethylamine were added. Thereafter, 22 g of t-butoxycarboxylic anhydride was added with ice cooling, and the mixture was stirred at room temperature for 3 hours. Next, the reaction solution was extracted with ethyl acetate and then concentrated to obtain the monomer (1).

<Test Example 1: Evaluation of solubility in component (S)>
The following resins (A-01) to (A-07) were evaluated for solubility in the component (S) by the following procedure. The molecular weight and dispersity of each resin were calculated from the GPC results, and the composition (ratio (mol%) of each structural unit) was calculated from ¹ H-NMR.
Moreover, the thermal decomposition temperature (Td) and glass transition temperature (Tg) of resin (A-01)-(A-07) were measured with the following method, respectively. Td (° C.) was measured with a thermal analyzer DSC6200 (product name, manufactured by Seiko Instrument) under a temperature rising condition of 10 ° C./min. Tg (° C.) was measured under a temperature rising condition of 10 ° C./min with a thermal analyzer TG / DTA6200 (product name, manufactured by Seiko Instrument).
(A-01): Mw = 8000 represented by the following chemical formula (A-01), Mw / Mn = 1.81, glass transition temperature (Tg) = 138.2 ° C., thermal decomposition temperature (Td) = 222. 3 ° C. copolymer. In formula (A-01), x ₁ : y ₁ = 37.0: 63.0 (molar ratio).
(A-02): A copolymer represented by the following chemical formula (A-02) having Mw = 6900, Mw / Mn = 1.61, Tg = 140.8 ° C., and Td = 219.8 ° C. Wherein _{(A-02), x 2} : y 2: z 2 = 27.6: 28.2: 43.2 (molar ratio).
(A-03): A copolymer represented by the following chemical formula (A-03): Mw = 7100, Mw / Mn = 1.79, Tg = 146.5 ° C., Td = 24.1 ° C. In formula (A-03), x ₃ : y ₃ : z ₃ = 33.6: 44.2: 22.2.
(A-04): A copolymer represented by the following chemical formula (A-04) having Mw = 7500, Mw / Mn = 1.65, Tg = 120.9 ° C., Td = 213.9 ° C. In formula (A-04), x ₄ : y ₄ : z ₄ = 18.1: 19.4: 62.5.
(A-05): Copolymer represented by the following chemical formula (A-05): Mw = 7400, Mw / Mn = 2.02, Tg = 134.1 ° C., Td = 218.9 ° C. Wherein _{(A-05), x 5} : y 5 = 54.9: is 45.1.
(A-06): A copolymer represented by the following chemical formula (A-06): Mw = 7700, Mw / Mn = 1.85, Tg = 135.9 ° C., Td = 213.5 ° C. In formula (A-06), x ₆ : y ₆ = 50.4: 49.6.
(A-07): Copolymer represented by the following chemical formula (A-07): Mw = 7500, Mw / Mn = 1.76, Tg = 100.8 ° C., Td = 218.5 ° C. In formula (A-07), x ₇ : y ₇ = 59.2: 40.8.

First, (S) component (23 ° C.) shown in Table 1 was added to (A-01) so that the resin concentration (mass%) shown in Table 1 was obtained. This was subjected to ultrasonic treatment (ultrasonic dissolution) or standing treatment for the time shown in Table 1. Table 1 shows the state before treatment (at the time of solvent addition) and after each treatment.
The following abbreviations have the following meanings.
DIAE: diisopentyl ether.
CNL: 1,8-cineole.
IBA: Isobutanol.

Next, (A-02) to (A-07) were evaluated for solubility in the component (S) by the following procedure.
First, (S) component (23 degreeC) shown in Table 2 was added with respect to each resin so that it might become the resin concentration (mass%) shown in Table 2, respectively, and the ultrasonic treatment for 30 minutes was performed. After the treatment, the resin was completely dissolved and the liquid became transparent, and the case where the resin did not become transparent was evaluated as x. The results are shown in Table 2. Moreover, the evaluation result of the above (A-01) is also shown in Table 2.

<Example 1>
(A-1) and DIAE were mixed and dissolved to prepare a resist coating film forming material having a resin concentration of 0.5% by mass.

The following evaluation was performed using the resist coating film forming material.
"Measurement of resist coating film formation and contact angle"
First, each component shown in Table 3 was mixed and dissolved to prepare a positive resist composition 1.

Each abbreviation in Table 3 has the following meaning, and the numerical value in [] is the blending amount (part by mass).
(A ′)-1: A copolymer represented by the following chemical formula (A ′)-1 and having Mw = 7000 and Mw / Mn = 1.8.
(A ′)-2: A copolymer represented by the following chemical formula (A ′)-2 and having Mw = 10000 and Mw / Mn = 1.8.
In the chemical formulas (A ′)-1 and (A ′)-2, the numerical value on the lower right of () indicates the ratio (mol%) of each structural unit.
(B ′)-1: a compound represented by the following formula (B ′)-1.
(B ′)-2: A compound represented by the following formula (B ′)-2.
(D ′)-1: tri-n-pentylamine.
(E ′)-1: salicylic acid.
(S ′)-1: γ-butyrolactone.
(S ′)-2: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.

Next, an organic antireflection film composition “ARC29A” (trade name, manufactured by Brewer Science Co., Ltd.) was applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to dry. As a result, an organic antireflection film having a thickness of 77 nm was formed. The positive resist composition 1 is applied onto the antireflection film using a spinner, prebaked (PAB) at 115 ° C. for 60 seconds on a hot plate, and dried to obtain a film thickness of 150 nm. The resist film was formed.
Next, the resist coating film forming material prepared above was applied onto the resist film using a spinner and heated at 90 ° C. for 60 seconds. As a result, a resist coating film having a thickness shown in Table 4 was formed on the resist film.
50 μL of water is dropped on the resist coating film side surface, and using a DROP MASTER-700 manufactured by Kyowa Interface Science Co., Ltd., a static contact angle, a falling angle, an advancing angle and a receding angle (in this example, these Are collectively referred to as contact angle, etc.).
As a reference example, the surface of the resist laminate without the above-described resist coating film, that is, the contact angle of the resist film surface was measured in the same manner as described above.
The results are shown in Table 4.

Further, a resist laminate is formed in the same manner as described above, and ArF excimer is used using an ArF exposure apparatus NSR-S-302A (Nikon Corp .; NA (numerical aperture) = 0.60, 2/3 annular illumination). Open frame exposure (exposure not through a mask) is performed with a laser (193 nm) (exposure amount 20 mJ / cm ² ), and the contact angle (contact angle after exposure, etc.) of the resist coating film side surface of the resist laminate is as described above. The measurement was performed in the same manner.
As a reference example, the surface of the resist laminate without the above-described resist coating film, that is, the contact angle of the resist film surface was measured in the same manner as described above.
The results are shown in Table 4.

  As shown in the above results, by providing a resist coating film on the resist film, the static contact angle and the dynamic contact angle (advanced forward) on the resist laminate surface compared to the reference example in which the resist coating film was not provided. Angle and receding angle) increased, and the falling angle decreased. From this result, it was confirmed that the formed resist coating film was a film having higher hydrophobicity than the underlying resist film.

"Elution evaluation in immersion exposure"
Using the resist coating film forming material of Example 1, a resist laminate was formed in the same manner as described above.
Next, using VRC310S (trade name, manufactured by SS Co., Ltd.), 1 drop (50 μl) of pure water is moved at room temperature at a constant linear velocity so as to draw a circle from the center of the wafer at room temperature. (Total contact area 221.56 cm ^{2 on the} surface of the resist laminate in contact with the droplets).
Thereafter, the droplets were collected and analyzed by an analyzer Agilent-HP1100 LC-MSD (trade name, manufactured by Agilent Technologies), and the cation part (PAG +) of the component (B ′) and the anion of the component (B ′) The elution amounts (no exposure) of parts (PAG-) and (D ′) components were determined. The results are shown in Table 5.
In Table 6, “Dinaftyl” indicates the cation moiety (dinaphthylphenylsulfonium) of (B ′)-1 and (B ′)-2. “Imine” and “PFBS” represent the anion moieties of (B ′)-1 and (B ′)-2, respectively.

In addition, a resist laminate is formed in the same manner as described above, and an ArF excimer laser (ArF exposure apparatus NSR-S302A (manufactured by Nikon; NA (numerical aperture) = 0.60, 2/3 annular illumination)) is used. 193 nm), and open frame exposure (exposure without a mask) was performed (exposure amount 20 mJ / cm ² ).
Next, the same analysis as described above was performed on the resist laminate after exposure. The results are shown in Table 5.

  As shown in Table 5, by forming a resist coating film using the resist coating film forming material of Example 1, in the immersion medium (water) both before and after immersion exposure. Material elution into the water was greatly reduced.

"Formation of resist pattern"
On the resist film formed in the same manner as described above, the resist coating film forming material is applied using a spinner and heated at 90 ° C. for 60 seconds to form a resist coating film having the thickness shown in Table 6. As a result, a resist laminate was obtained.
Next, an ArF excimer laser (193 nm) was applied to the resist laminate using an ArF exposure apparatus NSR-S-302 (Nikon Corp .; NA (numerical aperture) = 0.60, 2/3 annular illumination). , And selectively irradiated through a mask pattern (6% halftone reticle).
Then, PEB treatment was performed at 110 ° C. for 60 seconds, and further developed with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution at 23 ° C. for 30 seconds, then washed with water for 30 seconds, and then shaken and dried.
As a reference example, the same operation as described above was performed except that the resist coating film was not formed.

When the surface of the resist laminate after development was observed with a scanning electron microscope, a line-and-space resist pattern (L / S pattern) having a line width of 200 nm and a pitch of 400 nm was formed in each example. In particular, the resist pattern when the film thickness of the resist coating film was 10 nm had a high cross-sectional rectangularity and a good shape. The roughness was also equal to or better than that of the reference example.
Further, the optimum exposure amount (Eop) at which the L / S pattern was formed was determined. The results are shown in Table 6.

<Examples 2 to 5>
The components (A) and (S) shown in Table 7 were mixed and dissolved to prepare a resist coating film forming material having a resin concentration of 0.5% by mass.

The following evaluation was performed using the resist coating film forming material.
"Measurement of resist coating film formation and contact angle"
In the same manner as in Example 1, the resist coating film was formed and the contact angle before exposure was measured. The results are shown in Table 8.

  As shown in the above results, by providing a resist coating film on the resist film, the static contact angle and the dynamic contact angle (advanced forward) on the resist laminate surface compared to the reference example in which the resist coating film was not provided. Angle and receding angle) increased, and the falling angle decreased. From this result, it was confirmed that the formed resist coating film was a film having higher hydrophobicity than the underlying resist film.

"Formation of resist pattern"
Next, the resist coating film forming material of Examples 3 to 4 was used, and the resist pattern was formed in the same manner as in Example 1 except that the mask pattern was a target having an L / S pattern with a line width of 130 nm. Formation was performed.
When the surface of the resist laminate after development was observed with a scanning electron microscope, an L / S pattern having a line width of 130 nm and a pitch of 260 nm was formed in any of the examples.
Further, the optimum exposure amount (Eop) at which the L / S pattern was formed was determined. The results are shown in Table 9.

<Examples 6 to 8>
The components (A) and (S) shown in Table 10 were mixed and dissolved to prepare a resist coating film forming material having a resin concentration of 0.5% by mass.

The following evaluation was performed using the resist coating film forming material.
"Measurement of resist coating film formation and contact angle"
In the same manner as in Example 1, the resist coating film was formed and the contact angle and the like were measured. The results are shown in Table 11.

Further, a resist film is formed in the same manner as described above, and a resist coating film having a thickness shown in Table 12 is formed on the resist film using the resist coating film forming material of Example 8 (90 By baking at 60 ° C. for 60 seconds, a resist laminate was obtained. The resist laminate is masked with an ArF excimer laser (193 nm) using an ArF exposure apparatus NSR-S-302A (Nikon Corp .; NA (numerical aperture) = 0.60, 2/3 annular illumination). Irradiation selectively through a pattern (6% halftone reticle) (exposure amount 31 mJ / cm ² , exposure amount 28 mJ / cm ² ). Further, PEB treatment was performed at 110 ° C. for 60 seconds. After the PEB treatment, development processing was further performed at 23 ° C. with an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution for 30 seconds to form an L / S pattern having a line width of 120 nm and a pitch of 240 nm. After the development treatment, the contact angle and the like of the surface of the resist coating film of the resist laminate (contact angle after development treatment, etc.) were measured in the same manner as described above.
The results are shown in Table 12.

  As shown in the above results, it was confirmed that by providing the resist coating film on the resist film, a sufficient hydrophobicity improving effect can be obtained even when the film thickness is about 5 to 10 nm.

"Formation of resist pattern"
“Resist pattern formation” is performed in the same manner as in Example 1 except that the resist coating film forming material of Example 8 is used and a mask pattern that targets an L / S pattern with a line width of 120 nm is used. It was.
As a result, even when the resist coating film was formed, an L / S pattern having a line width of 120 nm and a pitch of 240 nm could be formed as in the reference example. Moreover, the cross-sectional shape of the formed L / S pattern had a high rectangularity and was a favorable shape.
Further, the optimum exposure amount (Eop) at which the L / S pattern was formed was determined. The results are shown in Table 13.
Thus, it was confirmed that even when the resist coating film was provided, a resist pattern could be formed with the same lithography characteristics as when the resist coating film was not provided.

"Elution evaluation in immersion exposure"
Using the resist coating film forming material of Example 8, elution in immersion exposure was evaluated in the same manner as in Example 1. The results are shown in Table 14.

As is clear from the above results, according to the resist coating film forming material of the present invention, the resist coating film can be formed on the resist film without damaging the resist film.
Further, the formed resist coating film has a high surface hydrophobicity, and can suppress substance elution from the resist film during immersion exposure. Therefore, the resist coating film forming material of the present invention is useful for immersion exposure applications.
Further, the resist coating film formed using the resist coating film forming material of the present invention can remove the exposed portion together with the underlying resist film by development when forming a resist pattern. Therefore, it is not necessary to provide a separate step for removing the resist coating film, and the resist pattern can be easily formed.

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

Claims (7)

At least a material for forming a resist coating film in which the resin component (A) whose alkali solubility is increased by the action of an acid is dissolved in an organic solvent (S),
The resin component (A) has a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester having an acid dissociable, dissolution inhibiting group. And
Resist coating film formation characterized in that the organic solvent (S) contains at least one organic solvent (S1) selected from the group consisting of an ether-based organic solvent having no hydroxyl group and an alcohol-based solvent Materials.

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; Y ¹ is an aliphatic cyclic group; Z is an organic group; a is an integer of 1 to 3; Is an integer from 0 to 2 and a + b = 1 to 3; c, d and e are each independently an integer from 0 to 3. ]   2. The resist coating film forming film according to claim 1, wherein the organic solvent (S1) is at least one selected from the group consisting of a cyclic or chain ether-based organic solvent having no hydroxyl group and an alcohol-based solvent. material.   The resist coating film forming material according to claim 2, wherein the organic solvent (S1) is at least one selected from the group consisting of diisopentyl ether, 1,8-cineol and isobutanol.   The resist coating film forming material according to claim 1, wherein Z in the general formula (a0-1) is a tertiary alkyloxycarbonyl group.   The said resin component (A) has the structural unit (a2) induced | guided | derived from the acrylate ester containing a lactone containing cyclic group further, For resist coating film formation as described in any one of Claims 1-4 material.   The resist coating according to claim 1, wherein the resin component (A) further has a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. Film forming material. A step of forming a resist film using a chemically amplified resist composition on a support, and a resist using the resist coating film forming material according to any one of claims 1 to 6 on the resist film. A resist pattern forming method including a step of forming a coating film to obtain a resist laminate, a step of exposing the resist laminate, and a step of developing the resist laminate to form a resist pattern.

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