JP4566820B2 - Negative resist composition and resist pattern forming method - Google Patents

Description

  The present invention relates to a negative resist composition and a resist pattern forming method.

In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, miniaturization has rapidly progressed 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 were used, but now KrF excimer laser (248 nm) is the center of mass production, and ArF excimer laser (193 nm) is mass-produced. It has begun to be introduced. Research is also being conducted on lithography technology using an F ₂ excimer laser (157 nm), EUV (extreme ultraviolet light), EB (electron beam) or the like as a light source (radiation source).

Such a resist for a short wavelength light source is required to have high resolution capable of reproducing a pattern with a fine dimension and high sensitivity to such a short wavelength light source. As one of the resists satisfying such conditions, a chemically amplified resist containing a base resin and an acid generator that generates an acid upon exposure is known. The chemically amplified resist includes an alkali in an exposed portion. There are a positive type in which the solubility is increased and a negative type in which the alkali solubility in the exposed portion is reduced.
Conventionally, as a negative resist composition used in a process using i-line or KrF excimer laser light (248 nm) as a light source, an acid generator, an alkali-soluble resin such as a novolac resin or polyhydroxystyrene, a melamine resin, A negative resist containing a combination with an amino resin such as a urea resin is used (for example, see Patent Document 1).

Further, negative resist compositions that can be applied to processes using an ArF excimer laser with a shorter wavelength have been proposed (for example, Non-Patent Documents 1 to 4, Patent Document 2).
For example, a negative resist composition containing a resin component having a carboxy group, a crosslinking agent having an alcoholic hydroxyl group, and an acid generator has been proposed. This is a type in which the resin component is changed from alkali-soluble to insoluble by the reaction of the carboxy group of the resin component and the alcoholic hydroxyl group of the crosslinking agent by the action of the acid generated from the acid generator.
A negative resist composition comprising a resin component having a carboxy group or carboxylic acid ester group and an alcoholic hydroxyl group, respectively, and an acid generator, wherein the carboxy group or carboxylic acid ester group in the resin component is alcoholic There has also been proposed a type in which a hydroxyl group is reacted between molecules by the action of an acid generated from an acid generator to change the resin component from alkali-soluble to insoluble.
Japanese Patent Publication No. 8-3635 JP 2000-206694 A Journal of Photopolymer Science and Technology (J. Photopolym. Sci. Tech.), Vol. 10, No. 4, 579-584 (1997) Journal of Photopolymer Science and Technology (J. Photopolym. Sci. Tech.), Vol. 11, No. 3, pp. 507-512 (1998) SPIE Advances in Resist Technology and Processing XIV, Vol. 3333, p417-424 (1998) SPIE Advances in Resist technology and Processing XIX, Vol. 4690 p94-100 (2002)

However, conventional negative resist compositions developed for ArF excimer lasers have insufficient solubility in alkaline developers. This leads to problems such as development residue when the film thickness is increased.
SUMMARY An advantage of some aspects of the invention is to provide a negative resist composition and a resist pattern forming method capable of improving solubility in an alkaline developer.

［式中、Ｒは水素原子、アルキル基、フッ素化アルキル基またはフッ素原子であり；ｍ、ｎ、ｐはそれぞれ独立して１〜５の整数である。］
で表される構成単位（ａ１１）であることを特徴とするネガ型レジスト組成物である。
本発明の第２の態様は、（Ａ）アルカリ可溶性樹脂成分、（Ｂ）露光により酸を発生する酸発生剤成分、および（Ｃ）架橋剤成分を含有するネガ型レジスト組成物であって、前記（Ａ）アルカリ可溶性樹脂成分が、フッ素化されたヒドロキシアルキル基を１つ有する脂肪族環式基を含有する構成単位（ａ１）と、フッ素化されたヒドロキシアルキル基を２つ以上有する脂肪族環式基を含有する構成単位（ａ２）とを含む高分子化合物（Ａ１）を含有し、前記構成単位（ａ２）が、下記一般式（ａ２−１）

［式中、Ｒは水素原子、アルキル基、フッ素化アルキル基またはフッ素原子であり；ｍ、ｎはそれぞれ独立して１〜５の整数であり；ｑは０または１〜５の整数であり；ｏは２又は３であり；Ｘは脂肪族環式基である。］
で表される構成単位（ａ２１）であることを特徴とするネガ型レジスト組成物である。
In order to achieve the above object, the first aspect of the present invention comprises (A) an alkali-soluble resin component, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component. A negative resist composition, wherein (A) the alkali-soluble resin component contains a structural unit (a1) containing an aliphatic cyclic group having one fluorinated hydroxyalkyl group, and a fluorinated hydroxy A polymer compound (A1) containing a structural unit (a2) containing an aliphatic cyclic group having two or more alkyl groups , wherein the structural unit (a1) is represented by the following general formula (a1-1):

[Wherein, R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom; m, n and p are each independently an integer of 1 to 5. ]
A negative resist composition characterized in that it is a structural unit (a11) represented by:
The second aspect of the present invention is a negative resist composition comprising (A) an alkali-soluble resin component, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component. The (A) alkali-soluble resin component contains a structural unit (a1) containing an aliphatic cyclic group having one fluorinated hydroxyalkyl group, and an aliphatic having two or more fluorinated hydroxyalkyl groups. A polymer compound (A1) containing a structural unit (a2) containing a cyclic group, wherein the structural unit (a2) is represented by the following general formula (a2-1):

[Wherein, R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom; m and n are each independently an integer of 1 to 5; q is an integer of 0 or 1 to 5; o is 2 or 3; X is an aliphatic cyclic group. ]
A negative resist composition characterized in that it is a structural unit (a21) represented by:

In the third aspect of the present invention, the negative resist composition of the first aspect of the present invention is applied onto a substrate, pre-baked, selectively exposed, and then subjected to PEB (post-exposure heating). The resist pattern forming method is characterized in that a resist pattern is formed by alkali development.

  ADVANTAGE OF THE INVENTION According to this invention, the negative resist composition which can improve the solubility with respect to an alkaline developing solution, and the resist pattern formation method are provided.

In the following description, the meanings of terms are as follows.
“Structural unit” refers to a monomer unit constituting a polymer (resin).
The “structural unit derived from an acrylate ester” means a structural unit constituted by cleavage of an ethylenic double bond of an acrylate ester. “Acrylic acid ester” includes not only an acrylic acid ester in which a hydrogen atom is bonded to a carbon atom at the α-position, but also a concept in which a substituent (an atom or group other than a hydrogen atom) is bonded to the α-position. To do. Examples of the substituent include a halogen atom such as a fluorine atom, a halogenated alkyl group such as an alkyl group and a fluorinated alkyl group, and the like.
In the “structural unit derived from an acrylate ester”, the term “α-position (α-position carbon atom)” means a carbon atom to which a carboxy group is bonded, unless otherwise specified.
The “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
“Exposure” is a concept that encompasses not only light irradiation but also radiation irradiation such as electron beam irradiation.

[Negative resist composition]
The negative resist composition of the present invention comprises (A) an alkali-soluble resin component (hereinafter sometimes referred to as (A) component) and (B) an acid generator component that generates acid upon exposure (hereinafter referred to as (B). Component) and (C) a crosslinking agent component (hereinafter also referred to as component (C)).
In such a negative resist composition, when an acid is generated from the component (B) by exposure (radiation irradiation) during formation of the resist pattern, the acid acts to crosslink between the component (A) and the component (C). Occurs and becomes insoluble in alkali.

<(A) component>
In the present invention, the component (A) includes a structural unit (a1) containing an aliphatic cyclic group having one fluorinated hydroxyalkyl group and an aliphatic group having two or more fluorinated hydroxyalkyl groups. A polymer compound (A1) containing a structural unit (a2) containing a cyclic group is contained.

・ Structural unit (a1)
In the resin for resist compositions of the present invention, by having the structural unit (a1), the effects of the present invention can be obtained and swelling of the resist pattern can be suppressed.

In the structural unit (a1), the aliphatic cyclic group has only one fluorinated hydroxyalkyl group.
In the fluorinated hydroxyalkyl group, a part or all of the remaining hydrogen atoms in the hydroxyalkyl group are substituted with fluorine in a hydroxyalkyl group in which part of the hydrogen atoms of the alkyl group is substituted with hydroxy groups. It is what. In the fluorinated hydroxyalkyl group, the hydrogen atom of the hydroxy group is easily liberated by fluorination.
In the fluorinated hydroxyalkyl group, the alkyl group is preferably linear or branched. Although carbon number of the said alkyl group is not specifically limited, 1-20 are preferable, 4-16 are more preferable, and it is most preferable that it is 4-12. The number of hydroxy groups is not particularly limited, but is preferably one.
Among them, as a fluorinated hydroxyalkyl group, a fluorinated alkyl group and / or a fluorine atom is bonded to the carbon atom to which the hydroxy group is bonded (here, the α-position carbon atom of the hydroxyalkyl group). Is preferred. In the fluorinated alkyl group bonded to the α-position, all of the hydrogen atoms of the alkyl group are preferably substituted with fluorine.

“Aliphatic” in “aliphatic cyclic group having a fluorinated hydroxyalkyl group” is a relative concept with respect to aromaticity, and means a group or compound having no aromaticity. It is defined as
The aliphatic cyclic group may be monocyclic or polycyclic. “Monocyclic aliphatic cyclic group” means a monocyclic group having no aromaticity, and “polycyclic aliphatic cyclic group” means a polycyclic group having no aromaticity. Means a group. In the structural unit (a1), the aliphatic cyclic group is preferably polycyclic.
An aliphatic cyclic group is a hydrocarbon group composed of carbon and hydrogen (alicyclic group), and a part of the carbon atoms constituting the ring of the alicyclic group is a heterogeneous group such as an oxygen atom, a nitrogen atom, or a sulfur atom. Heterocyclic groups and the like substituted with atoms are included. As the aliphatic cyclic group, an alicyclic group is preferable.
The aliphatic cyclic group may be either saturated or unsaturated, but is preferably saturated because it is highly transparent to ArF excimer laser and the like, and has excellent resolution and depth of focus (DOF). .
The aliphatic cyclic group preferably has 5 to 15 carbon atoms.

Specific examples of the aliphatic cyclic group include the following.
That is, examples of the monocyclic group include a group in which two or more hydrogen atoms are removed from a cycloalkane including a hydrogen atom substituted with a fluorinated hydroxyalkyl group (hereinafter the same). More specifically, a group in which two or more hydrogen atoms have been removed from cyclopentane or cyclohexane can be mentioned, and a group in which two hydrogen atoms have been removed from cyclohexane is preferred.
Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, or the like. More specifically, a group in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.
In addition, such polycyclic groups are appropriately selected from those proposed as many constituting acid dissociable, dissolution inhibiting groups in, for example, positive photoresist composition resins for ArF excimer laser processes. Can be used.
Of these, groups in which two hydrogen atoms have been removed from cyclohexane, adamantane, norbornane, and tetracyclododecane are preferred because they are readily available in the industry.
Of these exemplified monocyclic groups and polycyclic groups, groups in which two hydrogen atoms have been removed from norbornane are particularly preferred.

  The structural unit (a1) is preferably a structural unit derived from an acrylate ester, and has a structure in which the aliphatic cyclic group is bonded to the ester group [—C (O) O—] of the acrylate ester (carboxyl The structure in which the hydrogen atom of the group is substituted with the above aliphatic cyclic group is preferred.

  More specifically, the structural unit (a1) represented by the following general formula (a1-1) is preferable as the structural unit (a1).

［式中、Ｒは水素原子、アルキル基、フッ素化アルキル基またはフッ素原子であり、ｍ、ｎ、ｐはそれぞれ独立して１〜５の整数である。］

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom, and m, n and p are each independently an integer of 1 to 5. ]

R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom.
The alkyl group is preferably a lower alkyl group having 5 or less carbon atoms. For example, a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group And a methyl group is preferable.
The fluorinated alkyl group is preferably a group in which one or more hydrogen atoms of a lower alkyl group having 5 or less carbon atoms are substituted with a fluorine atom. Specific examples of the alkyl group are the same as described above.
The hydrogen atoms substituted with fluorine atoms may be part or all of the hydrogen atoms constituting the alkyl group.
In R, a hydrogen atom or an alkyl group is preferable, a hydrogen atom or a methyl group is particularly preferable, and a hydrogen atom is most preferable.
M and n are each independently an integer of 1 to 5, preferably an integer of 1 to 3, and most preferably 1.
p is an integer of 1 to 5, preferably an integer of 1 to 3, and 1 is most preferable.

  Among the structural units (a11) represented by the general formula (a1-1), α, α′-bis- (trifluoromethyl) -bicyclo [2.2.1] hept-5-ene-2-ethanol acrylate (In the examples described later, the structural unit derived from the monomer NBHFAA) is preferable from the viewpoint of effects, easy synthesis, and high etching resistance.

The structural unit (a1) can be used alone or in combination of two or more.
In the polymer compound (A1), the proportion of the structural unit (a1) is preferably from 30 to 80 mol%, more preferably from 35 to 70 mol%, more preferably from 40 to 65, based on the total of all the structural units of (A1). More preferred is mol%, and most preferred is 40 to 60 mol%. The effect by containing a structural unit (a1) is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

・ Structural unit (a2)
In the resin for resist compositions of the present invention, by containing the structural unit (a2), solubility in an alkali developer can be improved while suppressing pattern swelling.

In the structural unit (a2), the aliphatic cyclic group has two or more fluorinated hydroxyalkyl groups.
The fluorinated hydroxyalkyl group in the structural unit (a2) is the same as the fluorinated hydroxyalkyl group in the structural unit (a1). However, in the structural unit (a2), the carbon number of the alkyl group in the fluorinated hydroxyalkyl group is preferably 1 to 20, more preferably 3 to 16, and most preferably 3 to 12.
The aliphatic cyclic group in the structural unit (a2) is the same as the aliphatic cyclic group in the structural unit (a1). However, in the structural unit (a2), a monocyclic group is more preferable. The aliphatic cyclic group preferably has 3 to 20 carbon atoms, and more preferably 4 to 15 carbon atoms.

Specific examples of the aliphatic cyclic group in the structural unit (a2) include the following.
That is, examples of the monocyclic group include a group in which three or more hydrogen atoms are removed from a cycloalkane including a hydrogen atom substituted with a fluorinated hydroxyalkyl group (hereinafter the same). More specifically, a group in which 3 or more hydrogen atoms have been removed from cyclopentane or cyclohexane can be mentioned, and a group in which 3 hydrogen atoms have been removed from cyclohexane is preferred.
Examples of the polycyclic group include groups in which three or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, or the like. More specifically, a group obtained by removing three or more hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane can be used.
In addition, such polycyclic groups are appropriately selected from those proposed as many constituting acid dissociable, dissolution inhibiting groups in, for example, positive photoresist composition resins for ArF excimer laser processes. Can be used.
Of these, groups in which three hydrogen atoms have been removed from cyclohexane, adamantane, norbornane, and tetracyclododecane are preferred because they are easily available in the industry.
Among these exemplified monocyclic groups and polycyclic groups, a group in which three hydrogen atoms are removed from cyclohexane is particularly preferable.

The structural unit (a2) is preferably a structural unit derived from an acrylate ester.
As the structural unit (a2), more specifically, the structural unit (a21) represented by the following general formula (a2-1) is preferable.

［式中、Ｒは水素原子、アルキル基、フッ素化アルキル基またはフッ素原子であり；ｍ、ｎはそれぞれ独立して１〜５の整数であり；ｑは０または１〜５の整数であり；ｏは２又は３であり；Ｘは脂肪族環式基である。］

[Wherein, R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom; m and n are each independently an integer of 1 to 5; q is an integer of 0 or 1 to 5; o is 2 or 3; X is an aliphatic cyclic group. ]

R in the general formula (a2-1) is the same as R in the general formula (a1-1). R in the general formula (a2-1) is preferably a hydrogen atom or an alkyl group, particularly preferably a hydrogen atom or a methyl group, and most preferably a methyl group.
q is 0 or an integer of 1 to 5, preferably 0 or 1, and most preferably 0.
m and n are the same as m and n in the above formula (a1-1).
o is 2 or 3, with 2 being most preferred.

X is an (o + 1) -valent aliphatic cyclic group. Here, “(o + 1) -valent aliphatic cyclic group” means a group obtained by removing (o + 1) hydrogen atoms bonded to carbon atoms constituting the ring skeleton of the aliphatic cyclic group.
The aliphatic cyclic group as X may be monocyclic or polycyclic, and is particularly preferably monocyclic because it is excellent in the effects of the present invention.
X preferably has 3 to 20 carbon atoms, and more preferably 4 to 15 carbon atoms.
Specific examples of X include groups in which (o + 1) hydrogen atoms have been removed from polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. More specifically, groups obtained by removing (o + 1) hydrogen atoms from cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like can be mentioned. In the present invention, X is particularly preferably a group obtained by removing (o + 1) hydrogen atoms from cyclohexane.

As the structural unit (a2), one type or a mixture of two or more types can be used.
In the polymer compound (A1), the proportion of the structural unit (a2) is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, based on the total of all the structural units of (A1), and 3 to 18 More preferred is mol%. The effect by containing a structural unit (a2) is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

・ Structural unit (a3)
The polymer compound (A1) is a structural unit derived from an acrylate ester in addition to the structural units (a1) and (a2), and a structural unit containing a hydroxyl group-containing chain or cyclic alkyl group It is preferable that (a3) is included.
The hydroxyl group (alcoholic hydroxyl group) of the structural unit (a3) has high alkali solubility and high crosslinkability with the component (C). Therefore, by incorporating the structural unit (a3) into the component (A1), The difference (contrast) in solubility between the exposed area and the unexposed area in the alkaline developer is improved.

The structural unit (a3) containing a hydroxyl group-containing chain or cyclic alkyl group is, in other words, a structural unit derived from an acrylate ester and containing a hydroxyl group-containing cyclic alkyl group (a31), and acrylic acid. One or both of structural units derived from an ester and containing a hydroxyl group-containing chain alkyl group (a32). The structural unit (a31) does not contain a “hydroxyl group-containing chain alkyl group”, and the structural unit (a32) does not contain a “hydroxyl group-containing cyclic alkyl group”.
In particular, when the structural unit (a31) containing a hydroxyl group-containing cyclic alkyl group is used, an effect of suppressing pattern swelling can be expected. Further, the resolution is high and the exposure margin is also improved. Furthermore, it is excellent in contrast and etching resistance.
On the other hand, when the structural unit (a32) containing a hydroxyl group-containing chain alkyl group is used, the hydrophilicity of the entire component (A1) is increased, and the resolution is improved. Further, the controllability of the crosslinking reaction during pattern formation becomes good, and the pattern shape and resolution are improved. Further, the film density tends to be improved, whereby the film loss during etching can be suppressed and the heat resistance tends to be improved.

..Structural unit (a31)
Examples of the structural unit (a31) derived from an acrylate ester and containing a hydroxyl group-containing cyclic alkyl group include, for example, a hydroxyl group-containing cyclic group in the ester group [—C (O) O—] of the acrylate ester. And a structural unit to which an alkyl group is bonded. Here, the “hydroxyl group-containing cyclic alkyl group” is a group in which a hydroxyl group is bonded to a cyclic alkyl group.
It is preferable that 1-3 hydroxyl groups are couple | bonded, for example, More preferably, it is one.
The cyclic alkyl group may be monocyclic or polycyclic, but is preferably a polycyclic group. Moreover, it is preferable that carbon number of a cyclic alkyl group is 5-15.

Specific examples of the cyclic alkyl group include the following.
Examples of the monocyclic alkyl group include groups in which 2 to 4 hydrogen atoms are removed from a cycloalkane including a hydrogen atom substituted with a hydroxyl group (hereinafter the same). More specifically, a group in which 2 to 4 hydrogen atoms have been removed from cyclopentane or cyclohexane can be mentioned. Among these, a group in which 2 to 4 hydrogen atoms have been removed from cyclohexane is preferred.
Examples of the polycyclic cyclic alkyl group include groups in which 2 to 4 hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. More specifically, a group obtained by removing 2 to 4 hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.
Such a cyclic alkyl group may be appropriately selected and used from among many proposed as constituting an acid dissociable, dissolution inhibiting group in a resin for a photoresist composition for ArF excimer laser process, for example. it can. Among these, groups in which 2 to 4 hydrogen atoms are removed from cyclohexane, adamantane, norbornane, and tetracyclododecane are easy to obtain industrially and are preferable.
Among these exemplified monocyclic groups and polycyclic groups, groups in which 2 to 4 hydrogen atoms are removed from cyclohexane and adamantane are preferable, and groups in which 2 to 4 hydrogen atoms are removed from adamantane are particularly preferable. Is preferred.

  As a specific example of the structural unit (a31), for example, a structural unit (a310) represented by general formula (a3-1) shown below is preferable.

［式中、Ｒは水素原子、アルキル基、フッ素化アルキル基またはフッ素原子であり、ｓは１〜３の整数である。］

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom, and s represents an integer of 1 to 3. ]

R in the general formula (a3-1) is the same as R in the general formula (a1-1). R in the general formula (a3-1) is preferably a hydrogen atom or an alkyl group, particularly preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.
s is an integer of 1 to 3, and 1 is preferable.
The bonding position of the hydroxyl group is not particularly limited, but is preferably bonded to the 3rd position of the adamantyl group.

..Structural unit (a32)
Examples of the structural unit (a32) derived from an acrylate ester and having a hydroxyl group-containing chain alkyl group include, for example, a chain formed on the ester group [—C (O) O—] of the acrylate ester. Examples thereof include a structural unit to which a hydroxyalkyl group is bonded.
As the structural unit having a hydroxyl group-containing chain alkyl group, a structural unit (a320) represented by general formula (a3-2) shown below is particularly desirable.

［式中、Ｒは水素原子、アルキル基、フッ素化アルキル基またはフッ素原子であり、Ｒ^１はヒドロキシアルキル基である。］

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom, and R ¹ represents a hydroxyalkyl group. ]

R in the formula (a3-2) is the same as R in the general formula (a1-1). R in the general formula (a3-2) is preferably a hydrogen atom or an alkyl group, particularly preferably a hydrogen atom or a methyl group, and most preferably a methyl group.
The hydroxyalkyl group as R ¹ is preferably a lower hydroxyalkyl group having 10 or less carbon atoms, more preferably a lower hydroxyalkyl group having 2 to 8 carbon atoms, still more preferably a straight chain having 2 to 4 carbon atoms. It is a chain-like lower hydroxyalkyl group.
The number of hydroxyl groups and the bonding position in the hydroxyalkyl group are not particularly limited, but are usually one and preferably bonded to the terminal of the alkyl group.

The structural unit (a3) can be used alone or in combination of two or more.
In the present invention, the structural unit (a3) preferably includes at least the structural unit (a31), and particularly preferably includes both the structural unit (a31) and the structural unit (a32).
When both the structural unit (a31) and the structural unit (a32) are used, the ratio (molar ratio) between the structural unit (a31) and the structural unit (a32) in the polymer compound (A1) is the structural unit (a31). : The structural unit (a32) is preferably in the range of 9: 1 to 1: 9, more preferably 9: 1 to 2: 8, and still more preferably 9: 1 to 3: 7. 8: 2 to 5: 5 is most preferable.
By blending the structural unit (a31) and the structural unit (a32) in a well-balanced manner, an appropriate contrast can be obtained and the resolution can be improved. In addition, etching resistance is improved. Furthermore, a good exposure margin can be obtained.
In particular, the structural unit (a3) preferably includes both the structural unit (a310) and the structural unit (a320) because the effects of the present invention are excellent.

  When the structural unit (a3) is contained in the polymer compound (A1), the ratio of the structural unit (a3) to the total of all the structural units of the polymer compound (A1), that is, the structural unit (a31) and the structural unit The total proportion of the units (a32) is preferably 10 to 70 mol%, more preferably 15 to 65 mol%, still more preferably 20 to 60 mol%, and most preferably 25 to 55 mol%. The effect by containing a structural unit (a3) is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

・ Structural unit (a4)
In addition, as the component (A1), as the structural units other than the structural units (a1) to (a3), structural units that are conventionally used for known resin components for chemically amplified resist compositions are appropriately used. be able to.
For example, the component (A1) may include a structural unit (a4) derived from an acrylate ester containing a lactone-containing monocyclic or polycyclic group.
The lactone here refers to one ring containing the —O—C (O) — structure, and this is counted as the first ring. Therefore, when it has only a 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.
In the structural unit (a4), one or more hydrogen atoms of the lactone-containing monocyclic or polycyclic group are substituted with a fluorinated hydroxyalkyl group.

  When the lactone-containing monocyclic or polycyclic group of the structural unit (a4) is used for forming a resist film, it increases adhesion of the resist film to the substrate and increases hydrophilicity with the developer. It is effective. In addition, the effect of suppressing swelling is improved.

As the structural unit (a4), any structural unit can be used without particular limitation as long as it has a lactone ring having both the ester structure (—O—C (O) —) and a ring structure.
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.
In particular, a group obtained by removing one hydrogen atom from a lactone-containing tricycloalkane having the following structural formula is advantageous in that it is easily available industrially.
Among lactone-containing polycyclic groups, those having norbornane lactone are preferred.

  More specifically, examples of the structural unit (a4) include structural units represented by general formulas (a4-1) to (a4-5) shown below.

［式中、Ｒは前記と同じである。Ｒ’はそれぞれ独立して水素原子、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の整数である。］）

[Wherein, R is the same as defined above. R ′ is independently a hydrogen atom, an alkyl group, or an alkoxy group having 1 to 5 carbon atoms, and m ′ is an integer of 0 or 1. ])

The alkyl group for R ′ in formulas (a4-1) to (a4-5) is the same as the alkyl group for R in formula (a1-1). In general formulas (a4-1) to (a4-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Among the above, units represented by general formulas (a4-2) and (a4-3) are most preferable.

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 polymer compound (A1), the proportion of the structural unit (a4) is preferably 1 to 70 mol% with respect to the total of all the structural units of the polymer compound (A1). 3 to 50 mol% is more preferable, and 5 to 20 mol% is more preferable. The effect by containing a structural unit (a4) is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

-Mass average molecular weight The mass average molecular weight (Mw; polystyrene-converted mass average molecular weight by gel permeation chromatography) of the polymer compound (A1) is preferably 2000 to 30000, more preferably 2000 to 10000, still more preferably 3000 to 7000. is there. By setting it within this range, a good dissolution rate in an alkaline developer can be obtained, which is preferable from the viewpoint of high resolution. Within this range, the lower the molecular weight, the better characteristics tend to be obtained. The dispersity (Mw / Mn) is about 1.0 to 5.0, preferably 1.0 to 2.5.

  The polymer compound (A1) can be obtained, for example, by radical polymerization of a monomer for deriving each structural unit by a conventional method.

As the component (A), one or more of the above polymer compounds (A1) can be mixed and used. In addition to the polymer compound (A1), other polymer compounds known for negative resist compositions can be contained in the component (A). The proportion of the component A1) is preferably 50% by mass or more, more preferably 80% by mass or more, and most preferably 100% by mass.
The content of the component (A) in the negative resist composition may be adjusted according to the resist film thickness to be formed.

<(B) component>
<Acid generator component (B)>
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.

  As the onium salt acid generator, for example, an acid generator represented by the following general formula (b-0) can be preferably used.

[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 optionally substituted aryl group; n 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. Also. 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%, particularly hydrogen atoms. Are preferably substituted with a fluorine atom 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, branched or cyclic 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 anthracenyl 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.
n 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.

  Among these, a compound represented by the following chemical formula (b-0-1) is preferable.

  The acid generator represented by general formula (b-0) can be used alone or in combination of two or more.

  As other onium salt-based acid generators represented by the general formula (b-0), for example, compounds represented by the following general formula (b-1) or (b-2) are also preferably used. It is done.

［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.
As the alkoxy group which may substitute the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group and an ethoxy group are most preferable.
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, it is most preferable that all of R ¹ ″ to R ³ ″ are phenyl groups.

R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group.
The linear 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. Also. 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%, and particularly those in which all hydrogen atoms are substituted with fluorine atoms. Since the strength of the acid is increased, it is preferable.
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. Of R ⁵ ″ to R ⁶ ″, two or more are preferably aryl groups, and all of R ⁵ ″ to R ⁶ ″ are most preferably 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-based acid generator include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, and triphenylsulfonium trifluoromethane. Sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethane Sulfonate, its heptafluoropropane sulphonate or its Nafluorobutane sulfonate, trifluoromethane sulfonate of monophenyldimethylsulfonium, heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof, trifluoromethane sulfonate of diphenyl monomethylsulfonium, heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof, (4- Trifluoromethanesulfonate of methylphenyl) diphenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of (4-methoxyphenyl) diphenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, tri (4 -Tert-bu E) phenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, diphenyl (1- (4-methoxy) naphthyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate Is mentioned. 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.

  Moreover, what replaced the anion part by the anion part represented by the following general formula (b-3) or (b-4) in the said general formula (b-1) or (b-2) 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 the present invention, the oxime sulfonate-based 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. . 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^２１、Ｒ^２２はそれぞれ独立に有機基を表す。］

[In formula (B-1), R ²¹ and R ²² each independently represents an organic group. ]

In the present invention, the organic group is a group containing a carbon atom, and has an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom (fluorine atom, chlorine atom, etc.)). It may be.
The organic group for R ²¹ is preferably a linear, branched or cyclic alkyl group or aryl group. 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 ²¹ is particularly preferably a C 1-4 alkyl group having no substituent or a C 1-4 fluorinated alkyl group.

As the organic group for R ²² , a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^22, the same alkyl groups and aryl groups as those described above for R ²¹ can be used.
R ²² 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^３１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^３２はアリール基である。Ｒ^３３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 ³¹ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³² is an aryl group. R ³³ is an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３４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^３５は２または３価の芳香族炭化水素基である。Ｒ^３６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 the formula (B-3), R ³⁴ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁵ is a divalent or trivalent aromatic hydrocarbon group. R ³⁶ is an alkyl group having no substituent or a halogenated alkyl group. p ′ is 2 or 3. ]

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent for R ³¹ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably carbon atoms. Numbers 1 to 6 are most preferable.
R ³¹ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³¹ is preferably fluorinated by 50% or more of the hydrogen atom of the alkyl group, more preferably 70% or more, and even more preferably 90% or more.

As the aryl group of R ³² , 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 anthracyl group, a phenanthryl group, or the like. 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 ³² 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 for R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³³ 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 ³³ preferably has 50% or more of the hydrogen atom of the alkyl group, 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 ³⁴ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^31. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁵ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³² .
Examples of the alkyl group or halogenated alkyl group having no substituent for R ³⁶ include the same alkyl groups or halogenated alkyl groups as those having no substituent for R ³³ .
p ′ is preferably 2.

Specific examples of oxime sulfonate acid generators 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-dichlorobenzylcyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzylcyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzylcyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope Nthenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Moreover, the compound represented by the following chemical formula is mentioned.

  Moreover, the example of a preferable compound is shown below among the compounds represented by the said general formula (B-2) or (B-3).

  Of the above exemplified compounds, the following three 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.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane (when A = 3) and 1,4-bis (phenylsulfonyldiazo) having the following structure. Methylsulfonyl) butane (when A = 4), 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane (when A = 6), 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane (A = 10) 1), 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane (when B = 2), 1,3-bis (cyclohexylsulfonyldiazomethylsulfonyl) propane (when B = 3), 1,6- Bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane (when B = 6) (For B = 10) 1,10-bis (cyclohexyl diazomethylsulfonyl) decane and the like.

  In the present invention, it is particularly preferable to use an onium salt having a fluorinated alkyl sulfonate ion as an anion as the component (B).

(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 the negative resist composition of this invention 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.

<(C) component>
The component (C) is not particularly limited, and can be arbitrarily selected from cross-linking agents used in chemically amplified negative resist compositions known so far.
Specifically, for example, 2,3-dihydroxy-5-hydroxymethylnorbornane, 2-hydroxy-5,6-bis (hydroxymethyl) norbornane, cyclohexanedimethanol, 3,4,8 (or 9) -trihydroxytri Aliphatic cyclic carbonization having a hydroxyl group or a hydroxyalkyl group or both such as cyclodecane, 2-methyl-2-adamantanol, 1,4-dioxane-2,3-diol, 1,3,5-trihydroxycyclohexane Examples thereof include hydrogen and oxygen-containing derivatives thereof.

In addition, amino group-containing compounds such as melamine, acetoguanamine, benzoguanamine, urea, ethylene urea, propylene urea, glycoluril are reacted with formaldehyde or formaldehyde and lower alcohol, and the hydrogen atom of the amino group is hydroxymethyl group or lower alkoxymethyl. And a compound substituted with a group.
Of these, those using melamine are melamine-based crosslinking agents, those using urea are urea-based crosslinking agents, those using alkylene ureas such as ethylene urea and propylene urea are alkylene urea-based crosslinking agents, and glycoluril is used. This was called a glycoluril-based crosslinking agent. The component (C) is preferably at least one selected from the group consisting of melamine-based crosslinking agents, urea-based crosslinking agents, alkylene urea-based crosslinking agents, and glycoluril-based crosslinking agents, and glycoluril-based crosslinking agents are particularly preferred. preferable.

  Melamine-based crosslinking agents include compounds in which melamine and formaldehyde are reacted to replace the amino group hydrogen atom with a hydroxymethyl group, and melamine, formaldehyde and lower alcohol are reacted to convert the amino group hydrogen atom into a lower alkoxy group. Examples include compounds substituted with a methyl group. Specific examples include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxybutyl melamine, and the like, among which hexamethoxymethyl melamine is preferable.

  Urea-based crosslinking agents include compounds in which urea and formaldehyde are reacted to replace amino group hydrogen atoms with hydroxymethyl groups, and urea, formaldehyde and lower alcohols are reacted to convert amino group hydrogen atoms into lower alkoxy groups. Examples include compounds substituted with a methyl group. Specific examples include bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, bisbutoxymethylurea and the like, with bismethoxymethylurea being preferred.

  As an alkylene urea type crosslinking agent, the compound represented by the following general formula (C-1) is mentioned.

（式中のＲ^１’とＲ^２’はそれぞれ独立に水酸基又は低級アルコキシ基であり、Ｒ^３’とＲ^４’はそれぞれ独立に水素原子、水酸基又は低級アルコキシ基であり、ｖは０又は１〜２の整数である。）

(In the formula, R ^{1 ′} and R ^{2 ′} are each independently a hydroxyl group or a lower alkoxy group, R ^{3 ′} and R ^{4 ′} are each independently a hydrogen atom, a hydroxyl group or a lower alkoxy group, and v is 0 or 1) It is an integer of ~ 2.)

When R ^{1 ′} and R ^{2 ′} are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. ^'And R ^2' R 1 may be the same or may be different from each other. More preferably, they are the same.
When R ^{3 ′} and R ^{4 ′} are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ^{3 ′} and R ^{4 ′} may be the same or different from each other. More preferably, they are the same.
v is 0 or an integer of 1 to 2, preferably 0 or 1.
As the alkylene urea crosslinking agent, a compound in which v is 0 (ethylene urea crosslinking agent) and / or a compound in which v is 1 (propylene urea crosslinking agent) are particularly preferable.

  The compound represented by the general formula (C-1) can be obtained by a condensation reaction of alkylene urea and formalin and by reacting this product with a lower alcohol.

  Specific examples of the alkylene urea crosslinking agent include, for example, mono and / or dihydroxymethylated ethylene urea, mono and / or dimethoxymethylated ethylene urea, mono and / or diethoxymethylated ethylene urea, mono and / or dipropoxy Ethylene urea-based crosslinking agents such as methylated ethylene urea, mono and / or dibutoxymethylated ethylene urea; mono and / or dihydroxymethylated propylene urea, mono and / or dimethoxymethylated propylene urea, mono and / or diethoxymethyl Propylene urea-based crosslinkers such as propylene urea, mono and / or dipropoxymethylated propylene urea, mono and / or dibutoxymethylated propylene urea; 1,3-di (methoxymethyl) 4,5-dihydroxy-2- Imidazolidinone, 1,3-di (Metoki Like, etc.) -4,5-dimethoxy-2-imidazolidinone.

Examples of the glycoluril-based crosslinking agent include glycoluril derivatives in which the N position is substituted with one or both of a hydroxyalkyl group and an alkoxyalkyl group having 1 to 4 carbon atoms. Such a glycoluril derivative can be obtained by a condensation reaction between glycoluril and formalin and by reacting this product with a lower alcohol.
Specific examples of the glycoluril-based crosslinking agent include, for example, mono, di, tri and / or tetrahydroxymethylated glycoluril, mono, di, tri and / or tetramethoxymethylated glycoluril, mono, di, tri and / or Examples include tetraethoxymethylated glycoluril, mono, di, tri and / or tetrapropoxymethylated glycoluril, mono, di, tri and / or tetrabutoxymethylated glycoluril.

As the component (C), one type may be used alone, or two or more types may be used in combination.
(C) As for the compounding quantity of a component, 3-30 mass parts is preferable with respect to 100 mass parts of (A) component, 3-15 mass parts is more preferable, and 5-10 mass parts is the most preferable. When the content of the component (C) is at least the lower limit value, the crosslinking formation proceeds sufficiently and a good resist pattern can be obtained. Moreover, when it is below this upper limit, the storage stability of the resist coating solution is good, and the deterioration of sensitivity with time is suppressed.

<(D) component>
The negative resist composition of the present invention further includes (D) a nitrogen-containing organic compound (hereinafter referred to as “component (D)”) as an optional component in order to improve the resist pattern shape, stability over time and the like. Can be blended.
Since a wide variety of components (D) have already been proposed, any known one may be used, but aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred. .

Examples of the aliphatic amine include amines (alkyl amines or alkyl alcohol amines) in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms. Specific examples thereof include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di-n-heptylamine, Dialkylamines such as di-n-octylamine and dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-heptyl Trialkylamines such as amine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n -Ok Noruamin, alkyl alcohol amines such as tri -n- octanol amine. Among these, alkyl alcohol amines and trialkyl amines are preferable, and alkyl alcohol amines are most preferable. Of the alkyl alcohol amines, triethanolamine and triisopropanolamine are most preferred.
These may be used alone or in combination of two or more.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

<(E) component>
The negative resist composition of the present invention includes an organic carboxylic acid as an optional component for the purpose of preventing sensitivity deterioration due to the blending of the component (D) and improving the resist pattern shape, stability over time, etc. Alternatively, phosphorus oxo acid or its derivative (E) (hereinafter referred to as component (E)) can be contained. In addition, (D) component and (E) component can also be used together, and any 1 type can also be used.
As the organic carboxylic acid, for example, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Phosphorus oxoacids or derivatives thereof include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester and other phosphoric acid or derivatives thereof such as phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid- Like phosphonic acids such as di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester and derivatives thereof, phosphinic acids such as phosphinic acid, phenylphosphinic acid and their esters Among these, phosphonic acid is particularly preferable.
(E) A component is used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

<Organic solvent (S)>
The negative resist composition of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as “(S) component”).
Any organic solvent may be used as long as it can dissolve each component to be used to form a uniform solution, and one or two kinds of conventionally known solvents for chemically amplified resists can be used. These can be appropriately selected and used.
For example, lactones such as γ-butyrolactone, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate Polyhydric alcohols such as dipropylene glycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof, cyclic ethers such as dioxane, Methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, pyruvate Le, methyl methoxypropionate, esters such as ethyl ethoxypropionate can be exemplified.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
A mixed solvent obtained by mixing propylene glycol monomethyl ether acetate (PGMEA) and a 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.
In addition, as the organic solvent, 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.
Examples of the polar solvent include PGME and EL, and among them, PGME is preferable.
When blending PGME as the polar solvent, the mass ratio of PGMEA: PGME is preferably 9: 1 to 1: 9, more preferably 8: 2 to 2: 8, and most preferably 7: 3 to 4: 6.
The amount of the organic solvent used is not particularly limited, but is a concentration that can be applied to a substrate and the like, and is appropriately set according to the coating film thickness. Generally, the solid concentration of the resist composition is 2 to 20 mass. %, Preferably 5-15% by mass.

<Other ingredients>
The negative resist composition of the present invention may further contain miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving applicability, dissolution inhibitors, Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added and contained as appropriate.

<Pattern formation method>
[Resist pattern formation method]
In the resist pattern forming method, the negative resist composition of the present invention is applied on a substrate, pre-baked, selectively exposed, then subjected to PEB (post-exposure heating), and alkali-developed to form a resist pattern. It is characterized by forming.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the negative resist composition is applied onto a substrate with a spinner or the like, and prebaked for 40 to 120 seconds, preferably 60 to 90 seconds under a temperature condition of 80 to 150 ° C., for example, an ArF exposure apparatus. After selectively exposing ArF excimer laser light through a desired mask pattern, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds under a temperature condition of 80 to 150 ° C. . Subsequently, this is developed using an alkaline developer, for example, an aqueous 0.1 to 10% by mass tetramethylammonium hydroxide solution. In this way, a resist pattern faithful to the mask pattern can be obtained.
For example, a silicon wafer is used as the substrate. An inorganic substrate made of SiON or SiN can also be used. An organic or inorganic antireflection film may be provided between the substrate and the coating layer of the resist composition.

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.
In particular, the negative resist composition of the present invention is effective for an ArF excimer laser. This is because high resolution is required for a process using an ArF excimer laser as an exposure light source. In the negative resist composition of the present invention, the dissolution rate is improved, and as a result, the resolution and shape are improved. This is because it is possible to meet such strict requirements. Moreover, it is because it can be set as a highly transparent structure with respect to an ArF excimer laser.

According to the negative resist composition of the present invention, it is possible to improve the solubility in an alkali developer and form a good resist pattern. This is because the use of the structural units (a1) and (a2) containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group allows the resist film to be dissolved in an alkali developer while suppressing pattern swelling. It is estimated that the speed (Rmax) is increased.
By improving the alkali solubility, it is possible to prevent development residue even when the thickness of the resist film is increased. In addition, development residues can be suppressed even when a pattern having a large area, which generally tends to generate development residues, is formed.
Further, by improving the solubility in an alkali developer, the resolution is improved and the shape of the resist pattern is also improved.
In particular, in the case of a conventional ArF negative resist, when a resist pattern is formed on an inorganic substrate made of SiON, SiN, or the like, the pattern base tends to be indented inward, and pattern collapse occurs. Although easy, according to the negative resist composition of the present invention, good resolution and pattern shape can be obtained even on an inorganic substrate.
In addition, since the resolution is improved, the exposure margin is also improved.
Furthermore, since the resolution and the pattern shape are improved, the depth of focus (DOF) characteristics are improved, and LER (line edge roughness) is suppressed. Note that LER is uneven unevenness of the line side wall.
Furthermore, since the structural units (a1) and (a2) have an aliphatic cyclic group having a high carbon density, etching resistance is also improved.

  The monomer used in the following synthesis examples is represented by the following chemical formula.

<Synthesis Example 1>
NBHFAA 13.91 g, Fch 4.52 g and AdOHA 6.0 g and 0.6 g of dimethyl azobisisoacetate as a polymerization initiator were dissolved in 150 ml of THF (tetrahydrofuran). Nitrogen bubbling was performed for about 10 minutes, and the mixture was stirred for 4 hours while heating using an oil bath at 70 ° C., and then cooled to room temperature. Next, after concentrating the reaction solution with an evaporator, the concentrated solution was dissolved in 75 ml of THF, and poured into 2000 ml of heptane to precipitate a polymer compound (resin), followed by filtration.
The obtained polymer compound was dried in a dryer at 40 ° C. for 24 hours to obtain 22.9 g of a white solid (yield 93.7%).
The obtained polymer compound is designated as (A) -1. The structure of (A) -1 was as follows, the mass average molecular weight (Mw) was 5600, and the dispersity (Mw / Mn) was 1.96. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 53/12/35.

<Synthesis Example 2>
20.7 g of a white solid (polymer compound) was obtained in the same manner as in Synthesis Example 1 except that the amount of monomer used in Synthesis Example 1 was changed to NBHFAA 13.54 g, Fch 2.08 g, and AdOHA 6.0 g. (Rate 95.7%).
Let the obtained high molecular compound be (A) -2. The structure of (A) -2 was the same as that of the polymer compound (A) -1, and the mass average molecular weight (Mw) was 4900 and the dispersity (Mw / Mn) was 1.90. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 56/6/38.

<Synthesis Example 3>
23.4 g of a white solid (polymer compound) was obtained in the same manner as in Synthesis Example 1 except that the amount of monomer used in Synthesis Example 1 was changed to 13.78 g of NBHFAA, 6.79 g of Fch, and 6.0 g of AdOHA. Rate 88.0%).
The obtained polymer compound is designated as (A) -3. The structure of (A) -3 was the same as that of the polymer compound (A) -1, and the mass average molecular weight (Mw) was 6300, and the dispersity (Mw / Mn) was 1.79. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 50/17/33.

<Synthesis Example 4>
NBHFAA 13.91 g, Fch 2.55 g and AdOHA 6.0 g, and HEMA 1.80 g, and 0.6 g of dimethyl azobisisoacetate as a polymerization initiator were dissolved in 200 ml of THF (tetrahydrofuran). Nitrogen bubbling was performed for about 10 minutes, and the mixture was stirred for 4 hours while heating using an oil bath at 70 ° C., and then cooled to room temperature. Next, after concentrating the reaction solution with an evaporator, the concentrated solution was dissolved in 120 ml of THF, and poured into 1000 ml of heptane to precipitate a polymer compound (resin), followed by filtration.
The obtained polymer compound was dried in a dryer at 40 ° C. for 24 hours to obtain 16.7 g of a white solid.
Let the obtained high molecular compound be (A) -4. The structure of (A) -4 was as follows, the mass average molecular weight (Mw) was 5200, and the dispersity (Mw / Mn) was 1.62. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n / o = 47/6/31/16.

<Synthesis Example 5>
NBHFAA 7.00 g, Fch 1.27 g, AdOHA 3.0 g, and HEMA 0.90 g and dimethyl azobisisoacetate 0.3 g as a polymerization initiator were dissolved in 200 ml of THF (tetrahydrofuran). Nitrogen bubbling was performed for about 10 minutes, and the mixture was stirred for 4 hours while heating using an oil bath at 70 ° C., and then cooled to room temperature. Next, after concentrating the reaction solution with an evaporator, the concentrated solution was dissolved in 120 ml of THF, and poured into 1000 ml of heptane to precipitate a polymer compound (resin), followed by filtration.
The obtained polymer compound was dried in a dryer at 40 ° C. for 24 hours to obtain 7.12 g of a white solid.
The obtained polymer compound is designated as (A) -5. The structure of (A) -5 was the same as that of the polymer compound (A) -4, the mass average molecular weight (Mw) was 3500, and the dispersity (Mw / Mn) was 1.58. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n / o = 47/6/31/16.

<Comparative Synthesis Example 1>
13.58 g of NBHFAA and 6.0 g of AdOHA, and 0.5 g of dimethyl azobisisoacetate as a polymerization initiator were dissolved in 200 ml of THF (tetrahydrofuran). Nitrogen bubbling was performed for about 10 minutes, and the mixture was stirred for 4 hours while heating using an oil bath at 70 ° C., and then cooled to room temperature. Next, after concentrating the reaction solution with an evaporator, the concentrated solution was dissolved in 120 ml of THF, and poured into 1000 ml of heptane to precipitate a polymer compound (resin), followed by filtration.
The obtained polymer compound was dried in a dryer at 40 ° C. for 24 hours to obtain 14.1 g of a white solid (yield 72.0%).
The obtained polymer compound is designated as (A) -6. The structure of (A) -6 was as follows, the mass average molecular weight (Mw) was 4000, and the dispersity (Mw / Mn) was 1.59. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / n = 60/40.

In Synthesis Examples 1 to 5 and Comparative Synthesis Example 1, the structural unit derived from NBHFAA is included in the structural unit (a1), the structural unit derived from Fch is included in the structural unit (a2), and from AdOHA The derived structural unit is included in the structural unit (a31), and the structural unit derived from HEMA is included in the structural unit (a32).
Molar ratios of the structural units (a1), (a2), (a31), and (a32) in the polymer compounds (A) -1 to (A) -6 obtained in Synthesis Examples 1 to 5 and Comparative Synthesis Example 1 (L, m, n, o), mass average molecular weight (Mw), and dispersity (Mw / Mn) are summarized in Table 1 below.

<Examples 1 to 5, Comparative Example 1>
A negative resist composition was prepared with the composition shown in Table 2 below.
In addition, the symbol in Table 2 represents the following compound. Moreover, the numerical value in [] of Table 2 represents a compounding ratio (unit; mass part).
(B) -1: Triphenylsulfonium trifluoromethanesulfonate.
(B) -2: A compound represented by the chemical formula (b-0-1).

(C) -1: Tetramethoxymethylated glycoluril MX270 (manufactured by Sanwa Chemical Co., Ltd.).
(C) -2: Tetrabutoxymethylated glycoluril E-2403 (manufactured by Sanwa Chemical Co., Ltd.).
(D) -1: Triisopropanolamine.
(D) -2: Triethanolamine.
(E) -1: salicylic acid.
(S1): PGME.
(S2): PGMEA / PGME = 6/4 mixed solvent.

The following evaluation was performed using the obtained negative resist composition.
<Evaluation of dissolution rate>
A negative resist composition is uniformly applied on an 8-inch silicon substrate using a spinner, prebaked (PAB) on a hot plate at 80 ° C. for 60 seconds, and dried to form a resist film having a thickness of 200 nm. Formed.
When the obtained resist film was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C., the dissolution rate (unit: nm / second) of the resist film per unit time was measured.
Specifically, a substrate on which a resist film having a film thickness of 200 nm is formed is immersed in the tetramethylammonium hydroxide aqueous solution, and the time required for the resist film to completely dissolve is measured. The amount of reduction (nm / second) of the resist film was determined, and this value was taken as the dissolution rate.
The measurement results are shown in Table 2 below.

<Evaluation of development residue>
A negative resist composition was uniformly applied on the substrate using a spinner, prebaked (PAB) on the hot plate under the conditions shown in Table 2 below, and dried to form a resist film having a thickness of 300 nm.
As the substrate, Examples 1, 2, 4 and 5 use an inorganic substrate made of SiON. In Example 3 and Comparative Example 1, an organic antireflection film composition “ARC-29” was formed on an 8-inch silicon substrate. (Trade name, manufactured by Brewer Science Co., Ltd.) was applied using a spinner, baked on a hot plate at 215 ° C. for 90 seconds, and dried to form an organic antireflection film having a thickness of 77 nm. It was.
Next, an ArF excimer laser (193 nm) was selectively irradiated through the mask pattern by an ArF exposure apparatus NSR-S302 (manufactured by Nikon; NA (numerical aperture) = 0.60, 2/3 annular illumination). .
Then, PEB treatment was performed under the conditions shown in Table 2 below, followed by paddle development with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, and then water rinsing with pure water for 30 seconds, followed by shaking and drying To form a 150 nm line and space pattern (pitch 375 nm).
The surface of the substrate on which the pattern was formed was observed with a scanning electron microscope, and the presence or absence of a development residue was evaluated according to the following criteria. The results are shown in Table 2 below.
○: No development residue was found.
X: Development residue was generated.

From the results of Table 2, as compared with Comparative Example 1 using (A) -6 as the component (A), the dissolution rates of Examples 1 to 5 are remarkably improved, and even in a resist film having a film thickness of 300 nm. No development residue was generated.

Claims (11)

A negative resist composition comprising (A) an alkali-soluble resin component, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component,
The (A) alkali-soluble resin component contains a structural unit (a1) containing an aliphatic cyclic group having one fluorinated hydroxyalkyl group, and an aliphatic having two or more fluorinated hydroxyalkyl groups. A polymer compound (A1) containing a structural unit (a2) containing a cyclic group ,
The structural unit (a1) is represented by the following general formula (a1-1)

[Wherein, R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom; m, n and p are each independently an integer of 1 to 5. ]
A negative resist composition, which is a structural unit represented by formula (a11) . The structural unit (a2) is represented by the following general formula (a2-1)

[Wherein, R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom; m and n are each independently an integer of 1 to 5; q is an integer of 0 or 1 to 5; o is 2 or 3; X is an aliphatic cyclic group. ]
The negative resist composition of Claim 1 which is a structural unit (a21) represented by these. A negative resist composition comprising (A) an alkali-soluble resin component, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component,
The (A) alkali-soluble resin component contains a structural unit (a1) containing an aliphatic cyclic group having one fluorinated hydroxyalkyl group, and an aliphatic having two or more fluorinated hydroxyalkyl groups. A polymer compound (A1) containing a structural unit (a2) containing a cyclic group,
The structural unit (a2) is represented by the following general formula (a2-1)

[Wherein, R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom; m and n are each independently an integer of 1 to 5; q is an integer of 0 or 1 to 5; o is 2 or 3; X is an aliphatic cyclic group. ]
A negative resist composition, which is a structural unit (a21) represented by:   The proportion of the structural unit (a1) is 30 to 80 mol% and the proportion of the structural unit (a2) is 1 to 25 mol% in all the structural units of the polymer compound (A1). The negative resist composition as described in any one of these.   The polymer compound (A1) is further a structural unit derived from an acrylate ester and containing a hydroxyl group-containing cyclic alkyl group (a31) and a structural unit derived from an acrylate ester The negative resist composition as described in any one of Claims 1-4 containing one or both of the structural unit (a32) containing a containing chain | strand-shaped alkyl group.   The negative resist composition according to claim 5, wherein the structural unit (a3) includes both the structural unit (a31) and the structural unit (a32). The structural unit (a31) is represented by the following general formula (a3-1)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom, and s represents an integer of 1 to 3. ]
The negative resist composition of Claim 5 or 6 containing the structural unit (a310) represented by these. The structural unit (a3) is represented by the following general formula (a3-2)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom, and R ¹ represents a hydroxyalkyl group. ] The negative resist composition as described in any one of Claims 5-7 containing the structural unit (a320) represented by these.   The said (C) crosslinking agent component is at least 1 sort (s) chosen from the group which consists of a melamine type crosslinking agent, a urea type crosslinking agent, an alkylene urea type crosslinking agent, and a glycoluril type crosslinking agent. Negative resist composition as described in the above item.   Furthermore, the negative resist composition as described in any one of Claims 1-9 containing (D) nitrogen-containing organic compound.   After apply | coating the negative resist composition as described in any one of Claims 1-10 on a board | substrate, prebaking and selectively exposing, PEB (post-exposure heating) is given and alkali image development is carried out. And forming a resist pattern.