JP2008107677A - Negative resist composition and method for forming resist pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative resist composition capable of giving a resist pattern with high rectangularity, and to provide a method for forming a resist pattern. <P>SOLUTION: The negative resist composition contains an alkali-soluble resin component (A), an acid generator component (B) generating an acid by exposure and a crosslinking agent component (C); wherein the alkali-soluble resin component (A) contains a structural unit (a0) expressed by general formula (a0) by 0.1 to 10 mol% with respect to the total of the whole structural units constituting the resin component (A), and a structural unit containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group. In formula (a0), R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; each of R<SP>1</SP>and R<SP>2</SP>independently represents a lower alkyl group or an alkoxy group; n<SP>1</SP>is an integer 0 to 2; n<SP>2</SP>is an integer 0 to 3; and p is an integer 1 to 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

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

  Conventionally, as a negative resist material 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 urea resin, etc. A chemically amplified negative resist composition containing a combination with an amino resin is used (see, for example, Patent Document 1).

Further, as a negative resist material applied to a process using an ArF excimer laser having a shorter wavelength, as a material having improved transparency with respect to an ArF excimer laser, for example, a resin component having a carboxy group, a crosslinking agent having an alcoholic hydroxyl group And a negative resist composition containing 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 both a carboxy group or carboxylic acid ester group and an alcoholic hydroxyl group, and an acid generator, wherein the carboxy group or carboxylic acid ester group and the alcoholic hydroxyl group in the resin component Have been proposed in which the resin component is changed from alkali-soluble to insoluble by reacting between the molecules by the action of an acid generated from an acid generator (for example, Non-Patent Documents 1 to 4, Patents). Reference 2).
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, when a resist pattern is formed on a support using the conventional negative resist composition as described above, for example, there is a problem that a resist pattern having a high rectangularity is difficult to obtain due to a skirt shape. .
This invention is made | formed in view of the said situation, Comprising: It aims at providing the negative resist composition which can form a resist pattern with high rectangularity, and a resist pattern formation method.

In order to achieve the above object, the present invention employs the following configuration.
That is, the first aspect of the present invention is a negative resist composition comprising an alkali-soluble resin component (A), an acid generator component (B) that generates an acid upon exposure, and a crosslinking agent component (C). In the alkali-soluble resin component (A), the structural unit (a0) represented by the following general formula (a0) is 0.1 to the total of all the structural units constituting the alkali-soluble resin component (A). It is a negative resist composition characterized by having a structural unit containing an aliphatic cyclic group having 10 mol% to 10 mol% and having a fluorinated hydroxyalkyl group.

［式中、Ｒは水素原子、ハロゲン原子、低級アルキル基またはハロゲン化低級アルキル基を表し；Ｒ^１およびＲ^２はそれぞれ独立して低級アルキル基またはアルコキシ基を表し；ｎ^１は０〜２の整数であり、ｎ^２は０〜３の整数であり、ｐは１〜３の整数である。］

In the formula, R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹ and R ² each represents a lower alkyl group or an alkoxy group; n ¹ is 0-2 is an integer, ^{n 2} is an integer of 0 to 3, p is an integer of 1 to 3. ]

  The second aspect of the present invention includes a step of forming a resist film on a support using the negative resist composition of the first aspect, a step of exposing the resist film, and developing the resist film. Then, a resist pattern forming method comprising a step of forming a resist pattern.

In the present specification and claims, the “structural unit” means a monomer unit (monomer unit) constituting a resin component (polymer).
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
“Lower alkyl group” means an alkyl group having 1 to 5 carbon atoms.
“Exposure” is a concept that encompasses not only light irradiation but also whole irradiation of radiation such as electron beam irradiation.

  According to the negative resist composition and the resist pattern forming method of the present invention, a resist pattern with high rectangularity can be formed.

≪Negative resist composition≫
The negative resist composition of the present invention is an alkali-soluble resin component (A) (hereinafter referred to as “component (A)”), an acid generator component (B) that generates acid upon exposure (hereinafter referred to as “component (B)”). ) And a crosslinking agent component (C) (hereinafter referred to as the component (C)).
Such a negative resist composition is alkali-soluble before exposure. When an acid is generated from the component (B) by exposure, the acid acts to cause crosslinking between the component (A) and the component (C). It becomes insoluble in alkali. Therefore, in the formation of the resist pattern, when the resist film formed by applying the negative resist composition on a support such as a substrate is selectively exposed, the exposed portion becomes alkali-insoluble, while the unexposed portion is It remains alkali-soluble and can be negatively developed to form a negative resist pattern.

<(A) component>
In this invention, (A) component has 0.1-10 mol% of structural unit (a0) represented by the said general formula (a0) with respect to the sum total of all the structural units which comprise (A) component. And a structural unit containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group (hereinafter referred to as “structural unit (a1)”). The component (A) has a specific proportion of the structural unit (a0) and the structural unit (a1), so that when a negative resist composition is formed, a resist pattern with high rectangularity can be formed.
In addition to the structural unit (a0) and the structural unit (a1), the component (A) further includes a structural unit derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group (hereinafter referred to as “structural unit (a2) ) ").).
The component (A) has a cyclic structure in addition to the structural unit (a0) and the structural unit (a1), or in addition to the structural unit (a0), the structural unit (a1), and the structural unit (a2). In addition, it is preferable to have a structural unit derived from acrylic acid having an alcoholic hydroxyl group in the side chain (hereinafter referred to as “structural unit (a3)”).

Here, in the present specification and claims, “acrylic acid” is not only acrylic acid (CH ₂ ═CH—COOH) in which a hydrogen atom is bonded to a carbon atom at α-position, but also a carbon atom at α-position. The concept includes α-substituted acrylic acid in which the hydrogen atom bonded to is substituted with other substituents, and acrylic acid derivatives such as the following acrylic esters. 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.
“Acrylic acid ester” is not only an acrylic acid ester in which a hydrogen atom is bonded to a carbon atom at the α-position, but also an α-substituted acrylic acid in which the hydrogen atom bonded to the carbon atom in the α-position is substituted with another substituent. The concept includes esters. 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 “acrylic acid” and “acrylic acid ester”, “α-position (α-position carbon atom)” refers to a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
“Structural unit derived from acrylic acid” means a structural unit formed by cleavage of an ethylenic double bond of acrylic acid.
“A structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
In acrylic acid and acrylic acid ester, as an alkyl group as a substituent at the α-position, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl And a lower linear or branched alkyl group such as a group, an isopentyl group and a neopentyl group.
The α-position of acrylic acid and acrylate ester is preferably a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group, and preferably a hydrogen atom, a fluorine atom, a lower alkyl group or a fluorinated group. A lower alkyl group is more preferable, and a hydrogen atom or a methyl group is more preferable in terms of industrial availability.

・ Structural unit (a0)
The structural unit (a0) is a structural unit represented by the general formula (a0).
In the general formula (a0), R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group. The halogen atom, lower alkyl group or halogenated lower alkyl group of R is the same as the halogen atom, lower alkyl group or halogenated lower alkyl group which may be bonded to the α-position of the acrylate ester, and is a hydrogen atom or methyl A group is particularly preferred, and a hydrogen atom is most preferred.
R ¹ and R ² each independently represents a lower alkyl group or an alkoxy group.
Examples of the lower alkyl group for R ¹ and R ² include the same lower alkyl groups as those described above for R.
As the alkoxy group for R ¹ and R ^2, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group and an ethoxy group are particularly preferable.
n ¹ is an integer of 0 to 2, preferably 0 or 1, and most preferably 0 because the effect of the present invention is improved.
n ² is an integer of 0 to 3, preferably 0 or 1, and most particularly preferably from 0 reasons industry.
p is an integer of 1 to 3, and is most preferably 1.

In the general formula (a0), the terminal oxygen atom of “—C (O) —O—” bonded to the α-position carbon atom may be bonded to the 1-position of the naphthyl group, It may be bonded to the 2nd position. Especially, it is preferable that it couple | bonds with the 1st-position.
The bonding position of the hydroxyl group may be any position other than the bonding position of the terminal oxygen atom.
When the terminal oxygen atom is bonded to the 1-position of the naphthyl group, when p is 1, the bonding position of the hydroxyl group may be any of the 2- to 8-positions of the naphthyl group, particularly the 4-position. Alternatively, the 5th position is preferred, and the 5th position is most preferred because it is readily available and inexpensive. When the terminal oxygen atom is bonded to the 2-position of the naphthyl group, the hydroxyl-bonding position may be any position other than the 2-position, and preferably the 6-position or the 7-position. The 6-position is particularly preferred.
As for the bonding position of the hydroxyl group, when p is 2 or 3, any position other than the bonding position of the terminal oxygen atom can be arbitrarily combined.
When n ¹ is 1, R ¹ may be substituted at any position other than the hydroxyl bonding position. When n ¹ is 2, the substitution position of R ¹ can be arbitrarily combined with any position other than the hydroxyl bonding position.
The substitution position of R ² may be any position other than the bonding position of the terminal oxygen atom when n ² is 1. When n ² is 2 or 3, the substitution position of R ² can be arbitrarily combined with a position other than the bonding position of the terminal oxygen atom.
When the substitution position of R ¹ is the 5th to 8th position, the substitution position of R ² is preferably the 1st to 4th position.

  Specific examples of the structural unit (a0) represented by the general formula (a0) are shown below.

  Among these, at least one type of structural unit selected from the chemical formulas (a0-1) to (a0-8) is preferable because the effects of the present invention are good, and among them, the chemical formula (a0-1) to At least one structural unit selected from (a0-4) is particularly preferred, and chemical formula (a0-1) or (a0-2) is most preferred.

In the component (A), the structural unit (a0) can be used alone or in combination of two or more.
The proportion of the structural unit (a0) in the component (A) is 0.1 to 10 mol% and 1 to 8 mol% with respect to the total of all the structural units constituting the component (A). Preferably, it is 3-7 mol% and most preferable. By being above the lower limit of the above range, a resist pattern with high rectangularity can be formed. On the other hand, by being below the upper limit value, the swelling of the pattern is suppressed and the resolution is improved. Moreover, the balance with other structural units is favorable.

・ Structural unit (a1)
The structural unit (a1) is a structural unit containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group.
The “fluorinated hydroxyalkyl group” is a group in which part or all of the hydrogen atoms bonded to the carbon atom of the alkyl group in the alkyl group having a hydroxy group (hydroxyl group) are substituted with a fluorine atom. In such a group, the hydrogen atom of the hydroxyl 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 hydroxyl groups is not particularly limited, but is preferably 1 or 2, and more preferably 1.
Among the above, as the fluorinated hydroxyalkyl group, a fluorinated alkyl group and / or a fluorine atom is bonded to a carbon atom to which a hydroxyl group is bonded (here, the α-position carbon atom of the hydroxyalkyl group). What is doing is preferable. In the fluorinated alkyl group bonded to the α-position, it is preferable that all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms.

The “aliphatic cyclic group” in the “aliphatic cyclic group having a fluorinated hydroxyalkyl group” may be a monocyclic group or a polycyclic group.
Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.
The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a 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.
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). .
It is preferable that carbon number of an aliphatic cyclic group is 5-15.
In the structural unit (a1), the aliphatic cyclic group is preferably a polycyclic group.

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 and 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 a polycyclic group is appropriately selected from those proposed as many constituting acid dissociable, dissolution inhibiting groups in, for example, a positive resist composition resin for ArF excimer laser process. 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 easily 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 acrylic acid, and in particular, an oxygen atom (—O—) at the terminal of the carbonyloxy group [—C (O) —O—] of the acrylate ester. And a structure in which the aliphatic cyclic group is bonded to each other (a structure in which a hydrogen atom of a carboxy group of acrylic acid is substituted with the aliphatic cyclic group).

  More specifically, the structural unit (a1) is preferably a structural unit represented by the following general formula (I).

［式中、Ｒは水素原子、ハロゲン原子、低級アルキル基またはハロゲン化低級アルキル基を表し；ｓ、ｔ、ｔ’はそれぞれ独立して１〜５の整数である。］

[Wherein, R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; and s, t and t ′ each independently represents an integer of 1 to 5. ]

In the formula (I), R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group. The halogen atom, lower alkyl group or halogenated lower alkyl group of R is the same as the halogen atom, lower alkyl group or halogenated lower alkyl group which may be bonded to the α-position of the acrylate ester, and is a hydrogen atom or methyl It is preferably a group, more preferably a hydrogen atom.
s is an integer of 1 to 5, preferably an integer of 1 to 3, and 1 is most preferable.
t is an integer of 1 to 5, preferably an integer of 1 to 3, and 1 is most preferable.
t ′ is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably an integer of 1 to 2, and 1 is most preferable.
In the structural unit (a1) represented by the general formula (I), a 2-norbornyl group or a 3-norbornyl group is bonded to the terminal oxygen atom of the carbonyloxy group [—C (O) —O—]. It is preferable. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

In the component (A), the structural unit (a1) can be used alone or in combination of two or more.
The proportion of the structural unit (a1) in the component (A) is preferably 10 to 80 mol%, and preferably 20 to 70 mol% with respect to the total of all the structural units constituting the component (A). Is more preferable, 40 to 60 mol% is particularly preferable, and 45 to 60 mol% is most preferable. By being above the lower limit of the above range, resist swelling is suppressed and resolution is improved. On the other hand, the balance with other structural units is favorable by being below an upper limit.

・ Structural unit (a2)
The structural unit (a2) is a structural unit derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group. When the component (A) having the structural unit (a2) is blended in the negative resist composition, the hydroxyl group (alcoholic hydroxyl group) of the structural unit (a2) is converted into an ( It reacts with the component (C), whereby the component (A) changes from a soluble property to an insoluble property in an alkaline developer.

The “hydroxyl group-containing aliphatic cyclic group” is a group in which a hydroxyl group is bonded to an aliphatic cyclic group.
The number of hydroxyl groups bonded to the aliphatic cyclic group is preferably 1 to 3, more preferably 1.
The aliphatic cyclic group may be a monocyclic group or a polycyclic group, but is preferably a polycyclic group. Moreover, it is preferable that it is an alicyclic hydrocarbon group. Moreover, it is preferable that it is saturated. Moreover, it is preferable that carbon number of an aliphatic cyclic group is 5-15.
Specific examples of the aliphatic cyclic group (the state before the hydroxyl group is bonded) include the same aliphatic cyclic groups as those described above for the structural unit (a1).
As the aliphatic cyclic group of the structural unit (a2), among the above, a cyclohexyl group, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are preferred because they are easily available in the industry. Of these, a cyclohexyl group and an adamantyl group are preferable, and an adamantyl group is particularly preferable.
In addition to the hydroxyl group, a linear or branched alkyl group having 1 to 4 carbon atoms may be bonded to the aliphatic cyclic group.

In the structural unit (a2), the hydroxyl group-containing aliphatic cyclic group is preferably bonded to the terminal oxygen atom of the carbonyloxy group [—C (O) —O—] of the acrylate ester.
In this case, in the structural unit (a2), another substituent may be bonded to the α-position (α-position carbon atom) of the acrylate ester instead of the hydrogen atom. Preferred examples of the substituent include a lower alkyl group, a halogenated alkyl group, and a halogen atom. These explanations are the same as those of R in the general formula (I) of the structural unit (a1), and among those capable of bonding to the α-position, a hydrogen atom or a lower alkyl group is preferred, A hydrogen atom or a methyl group is particularly preferred, and a hydrogen atom is most preferred.

  As a specific example of the structural unit (a2), for example, a structural unit represented by the following general formula (II) is preferable.

［式中、Ｒは前記と同じであり；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；ｒ’は１〜３の整数である。］

[Wherein, R is the same as above; R ″ is a hydrogen atom, a lower alkyl group or an alkoxy group having 1 to 5 carbon atoms; r ′ is an integer of 1 to 3]

In the general formula (II), R is the same as described for R in the general formula (I).
R ″ is a hydrogen atom, a lower alkyl group or an alkoxy group having 1 to 5 carbon atoms. The lower alkyl group for R ″ is the same as the lower alkyl group for R.
In the general formula (II), R and R ″ are most preferably hydrogen atoms.
r ′ is an integer of 1 to 3, and is preferably 1.
The bonding position of the hydroxyl group is not particularly limited, but is preferably bonded to the position of the 3rd position of the adamantyl group.

In the component (A), the structural unit (a2) can be used alone or in combination of two or more.
The proportion of structural unit (a2) in component (A) is preferably 10 to 60 mol%, and preferably 10 to 50 mol%, based on the total of all structural units constituting component (A). Is more preferable, and it is still more preferable that it is 20-40 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 structural unit (a3) is a structural unit derived from acrylic acid having no cyclic structure and having an alcoholic hydroxyl group in the side chain.
When the component (A) having the structural unit (a3) is added to the negative resist composition, the alcoholic hydroxyl group of the structural unit (a3) is generated from the component (B) together with the hydroxyl group of the structural unit (a2). It reacts with the component (C) by the action of an acid.
For this reason, the component (A) is likely to change from a soluble property to an insoluble property in an alkaline developer, and an effect of improving the resolution can be obtained. Moreover, film loss can be suppressed. Moreover, the controllability of the crosslinking reaction during pattern formation is improved. Furthermore, the film density tends to improve. Thereby, there exists a tendency for heat resistance to improve. Furthermore, etching resistance is also improved.

“Having no cyclic structure” means having no aliphatic cyclic group or aromatic group. The structural unit (a3) is clearly distinguished from the structural unit (a2) by not having a cyclic structure.
Examples of the structural unit having an alcoholic hydroxyl group in the side chain include a structural unit having a hydroxyalkyl group.
Examples of the hydroxyalkyl group include those similar to the hydroxyalkyl group in the “fluorinated hydroxyalkyl group” mentioned in the structural unit (a1).
For example, the hydroxyalkyl group may be directly bonded to the α-position carbon atom of the main chain (the portion where the ethylenic double bond of acrylic acid is cleaved), or may be substituted with the hydrogen atom of the carboxy group of acrylic acid. You may comprise ester. In the structural unit (a3), it is preferable that at least one or both of these have a hydroxyalkyl group.
When a hydroxyalkyl group is not bonded to the α-position, an alkyl group, a halogenated alkyl group or a halogen atom may be bonded to the α-position carbon atom instead of a hydrogen atom. About these, Preferably, it is the same as that of the description about R in the said general formula (I).

  As the structural unit (a3), a structural unit represented by the following general formula (III) is preferable because of excellent effects of the present invention.

［式中、Ｒ^４は水素原子、アルキル基、ハロゲン化アルキル基、ハロゲン原子またはヒドロキシアルキル基であり；Ｒ^３は水素原子、アルキル基またはヒドロキシアルキル基である。ただし、Ｒ^３、Ｒ^４の少なくとも一方はヒドロキシアルキル基である。］

[Wherein, R ⁴ represents a hydrogen atom, an alkyl group, a halogenated alkyl group, a halogen atom or a hydroxyalkyl group; R ³ represents a hydrogen atom, an alkyl group or a hydroxyalkyl group. However, at least one of R ³ and R ⁴ is a hydroxyalkyl group. ]

R ⁴ is a hydrogen atom, an alkyl group, a halogenated alkyl group, a halogen atom or a hydroxyalkyl group.
The hydroxyalkyl group in R ⁴ is preferably a hydroxyalkyl group having 10 or less carbon atoms, preferably a linear or branched chain, more preferably a hydroxyalkyl group having 2 to 8 carbon atoms, Most preferred is a hydroxymethyl group or a hydroxyethyl group. The number of hydroxyl groups and the bonding position are not particularly limited, but are usually one and preferably bonded to the terminal of the alkyl group.
The alkyl group in R ⁴ is preferably an alkyl group having 10 or less carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and most preferably an ethyl group or a methyl group.
The halogenated alkyl group for R ⁴ is preferably a lower alkyl group having 5 or less carbon atoms (preferably an ethyl group or a methyl group), and part or all of the hydrogen atoms are substituted with halogen atoms (preferably fluorine atoms) Group.
Examples of the halogen atom in R ⁴ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
Examples of the alkyl group and hydroxyalkyl group for R ³ include the same groups as the alkyl group and hydroxyalkyl group for R ⁴ .
In the general formula (III), at least one of R ³ and R ⁴ is a hydroxyalkyl group.

Specifically, as the structural unit represented by the general formula (III), a structural unit derived from α- (hydroxyalkyl) acrylic acid (however, a structural unit derived from an acrylate ester is not included here). ), Structural units derived from α- (hydroxyalkyl) acrylic acid alkyl esters, and structural units derived from (α-alkyl) acrylic acid hydroxyalkyl esters.
Among these, when the structural unit (a3) includes a structural unit derived from an α- (hydroxyalkyl) acrylic acid alkyl ester, it is preferable from the viewpoint of improving the effect and improving the film density. A structural unit derived from (hydroxymethyl) acrylic acid ethyl ester or α- (hydroxymethyl) acrylic acid methyl ester is preferred.
Moreover, when the structural unit (a3) includes a structural unit derived from (α-alkyl) acrylic acid hydroxyalkyl ester, it is preferable in terms of crosslinking efficiency. Among these, a structural unit derived from α-methyl-acrylic acid hydroxyethyl ester or α-methyl-acrylic acid hydroxymethyl ester is preferable.

In the component (A), the structural unit (a3) can be used alone or in combination of two or more.
The proportion of the structural unit (a3) in the component (A) is preferably 5 to 50 mol%, and preferably 5 to 40 mol% with respect to the total of all the structural units constituting the component (A). Is more preferable, 5 to 30 mol% is particularly preferable, and 10 to 25 mol% is most preferable. 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.

-Other structural unit (A) component may have the other structural unit which can be copolymerized as structural units other than said each structural unit (a0) and (a1)-(a3).
As such a constitutional unit, a constitutional unit conventionally used for a resin component known for chemical amplification resist compositions can be used. Examples thereof include a structural unit (a4) derived from an acrylate ester containing a lactone-containing monocyclic or polycyclic group.
When the lactone-containing monocyclic or polycyclic group of the structural unit (a4) is used for forming a resist film, it increases the adhesion of the resist film to a substrate or the like, or increases the hydrophilicity with a developer. It is effective above. In addition, the effect of suppressing swelling is improved.
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 is substituted with a fluorinated hydroxyalkyl group. .

As the structural unit (a4), any structural unit can be used as long as it has a lactone ring having both the ester structure (—O—C (O) —) and a ring structure. It is.
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 the structural unit (a4), another substituent may be bonded to the α-position (α-position carbon atom) instead of a hydrogen atom. Preferred examples of the substituent include a lower alkyl group, a halogenated alkyl group, and a halogen atom.
Description of these substituents is the same as that of R in the general formula (I) of the structural unit (a1), and among those capable of bonding to the α-position, a hydrogen atom or a lower alkyl group is preferable. A hydrogen atom or a methyl group is particularly preferable, and a hydrogen atom is most preferable.

  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は水素原子、ハロゲン原子、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のアルキレン基又は酸素原子である。］

[Wherein, R is a hydrogen atom, a halogen 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; 1 is an integer of 1; A is an alkylene group having 1 to 5 carbon atoms or an oxygen atom. ]

R in the general formulas (a4-1) to (a4-5) is the same as R in the structural unit (a1).
The lower alkyl group for R ′ is the same as the lower alkyl group for R in the structural unit (a1).
In general formulas (a4-1) to (a4-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Specific examples of the alkylene group having 1 to 5 carbon atoms of A include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
As the structural unit (a4), structural units represented by general formula (a4-2) or general formula (a4-3) are particularly preferable.

In the component (A), the structural unit (a4) can be used alone or in combination of two or more.
When the structural unit (a4) is contained in the component (A), the proportion of the structural unit (a4) in the component (A) is 1 to 40 mol with respect to the total of all the structural units constituting the component (A). %, More preferably 10 to 40 mol%, and most preferably 10 to 25 mol%. 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.

In this invention, (A) component has 0.1-10 mol% of structural units (a0) with respect to the sum total of all the structural units which comprise this (A) component, and has structural unit (a1). A resin (copolymer) having a structural unit (a2) and / or a structural unit (a3).
Examples of the resin include a copolymer having the structural unit (a0) and the structural unit (a1); a copolymer having the structural unit (a0), the structural unit (a1), and the structural unit (a2); ), A copolymer having the structural unit (a1), the structural unit (a2), and the structural unit (a3). Especially, the copolymer which has a structural unit (a0), a structural unit (a1), a structural unit (a2), and a structural unit (a3) is preferable. However, in any copolymer, the proportion of the structural unit (a0) in each copolymer is 0.1 to 10 mol%.
Among the above, a copolymer having 0.1 to 10 mol% of the structural unit (a0) and having the structural units (a1) to (a3) other than the structural unit (a0) as main components is particularly preferable.
Here, “main component” means that the proportion of the structural units (a1) to (a3) is 50 mol% or more with respect to the total of all the structural units constituting the copolymer, preferably 70 It is at least mol%, more preferably at least 80 mol%. Most preferably, it is the total amount excluding the structural unit (a0), that is, the component (A) is a co-polymer consisting of the structural unit (a0), the structural unit (a1), the structural unit (a2), and the structural unit (a3). The coalescence is most preferred.

  The resin (copolymer) suitable as the component (A) preferably includes a combination of structural units such as the following formula (A-1).

［式中、Ｒは前記と同じである。］

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

  In the structural unit corresponding to the structural unit (a0) in formula (A-1), the oxygen atom at the terminal of “—C (O) —O—” bonded to the α-position carbon atom is a naphthyl group. Those having a 1-position and a hydroxyl group bonded to the 5-position are preferred.

  The component (A) can be obtained, for example, by synthesizing a monomer that induces each structural unit by a method of radical polymerization by a conventional method, a method described in International Publication No. 2004/076495, or the like.

The mass average molecular weight (Mw; polystyrene-converted mass average molecular weight by gel permeation chromatography) of the component (A) is preferably 2000 to 30000, more preferably 2000 to 10000, and further preferably 3000 to 8000. By setting it within this range, a good dissolution rate in an alkali developer can be obtained, which is preferable from the viewpoint of high resolution. A lower mass average molecular weight in this range is preferable because good characteristics tend to be obtained.
Further, the dispersity (Mw / number average molecular weight (Mn)) is preferably 1.0 to 5.0, and more preferably 1.0 to 2.5.

In this invention, (A) component can be used individually by 1 type or in mixture of 2 or more types.
Further, the component (A) is known for use in negative resist compositions other than the above-exemplified copolymer having at least a specific proportion of the structural unit (a0) and the structural unit (a1). It is also possible to appropriately contain other polymer compounds such as hydroxystyrene resin, novolac resin, acrylic resin and the like.
In the present invention, 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>
The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

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

［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 of 1 to 3. ]

In 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%. In particular, 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 represents 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 ^R52 , the alkyl group is linear or branched, and the number of carbon atoms 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, 50 to 100% of the total number of hydrogen atoms are preferably substituted with halogen atoms, and more preferably all are substituted.
In R ⁵² , the alkoxy group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly preferably 1 to 4, and further 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, and an anthracenyl group. From the viewpoints of effects and absorption of exposure light such as ArF excimer laser, a phenyl group is preferred.
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.

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

  Specific examples of the onium salt acid generators represented by the formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, tri (4-methylphenyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or the same 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 ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less 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 or a fluorinated alkyl group having 1 to 4 carbon atoms which has no substituent.

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

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

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

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

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

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

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more, 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 anthracyl group, or a phenanthryl group. And heteroaryl groups in which some of the carbon atoms constituting the ring of these groups are substituted with heteroatoms such as oxygen, sulfur, and nitrogen atoms. 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 for 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, more preferably 70% or more, and even more preferably 90% or more fluorinated. This is preferable because the strength of the acid is increased. Most preferred 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 having no substituent as R ³⁵ described above.
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]), pamphlet of International Publication No. 04/074242, An oxime sulfonate-based acid generator disclosed in Examples 1 to 40) on pages 65 to 85 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

  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.
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).
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 or an oxygen-containing derivative 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 and a compound having an epoxy group.
Of these, those using melamine are melamine crosslinking agents, those using urea are urea crosslinking agents, those using alkylene ureas such as ethylene urea and propylene urea are alkylene urea crosslinking agents, and glycoluril is used. What was used was a glycoluril-based crosslinking agent, and what used a compound having an epoxy group was called an epoxy-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, glycoluril-based crosslinking agents, and epoxy-based crosslinking agents. Uril-based crosslinking agents are preferred.

  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, etc. Among them, bismethoxymethylurea is preferable.

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

［式中のＲ^５’とＲ^６’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。］

[Wherein R ⁵ ′ and R ⁶ ′ 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 ⁵ ′ and R ⁶ ′ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ⁵ ′ and R ⁶ ′ may be the same or 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.

The epoxy-based crosslinking agent is not particularly limited as long as it has an epoxy group, and can be arbitrarily selected and used. Among them, those having two or more epoxy groups are preferable. By having two or more epoxy groups, crosslinking reactivity is improved.
The number of epoxy groups is preferably 2 or more, more preferably 2 to 4, and most preferably 2.
The following are suitable as the epoxy-based crosslinking agent.

(C) A component may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the component (C) is preferably 1 to 50 parts by mass, more preferably 3 to 30 parts by mass, further preferably 3 to 15 parts by mass with respect to 100 parts by mass of the component (A ″). When the content of the component (C) is not less than the lower limit, crosslinking formation proceeds sufficiently and a good resist pattern with less swelling is obtained. In addition, the storage stability of the resist coating solution is good, and the deterioration of sensitivity over time is suppressed.

<(D) component>
The negative resist composition of the present invention further contains a nitrogen-containing organic compound (D) (hereinafter referred to as “component (D)”) as an optional component in order to improve the resist pattern shape, the stability over time, and the like. It is preferable to contain.
Since a wide variety of components (D) have already been proposed, any known one may be used. Cyclic amines, aliphatic amines, particularly secondary aliphatic amines and tertiary fats may be used. Group amines are preferred. Here, the aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include amines (alkyl amines or alkyl alcohol amines) in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms. Specific examples thereof include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di-n-heptylamine, Dialkylamines such as di-n-octylamine and dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-heptyl Trialkylamines such as amine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n -Ok Noruamin, alkyl alcohol amines such as tri -n- octanol amine.
Among these, alkyl alcohol amines and trialkyl amines are preferable, and alkyl alcohol amines are most preferable. Of the alkyl alcohol amines, triethanolamine and triisopropanolamine are most preferred.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
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.

<Optional component>
The negative resist composition of the present invention includes, as optional components, organic carboxylic acids, phosphorus oxoacids and derivatives thereof for the purpose of preventing sensitivity deterioration and improving the resist pattern shape, retention stability over time, etc. At least one compound (E) selected from the group consisting of (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids and derivatives thereof include phosphoric acid, phosphonic acid, phosphinic acid and the like, and among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of the phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
As the component (E), an organic carboxylic acid is preferable, and salicylic acid is particularly preferable.
(E) A component is used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

  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.

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).
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. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-amyl ketone, methyl isoamyl ketone, 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol A compound having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, or propylene glycol monoacetate, monomethyl ether, monoethyl ether of the polyhydric alcohol or the compound having an ester bond, A monoalkyl ether such as monopropyl ether or monobutyl ether or an ether bond such as monophenyl ether Derivatives of polyhydric alcohols such as propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred among these; cyclic ethers such as dioxane, methyl lactate, lactic acid Esters such as ethyl (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, di Aromatic organic solvents such as benzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, amylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. Can be mentioned.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Of these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is preferable. The mixing ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, but is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
The amount of the component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is It is used in a range of 2 to 20% by mass, preferably 5 to 15% by mass.

The negative resist composition of the present invention has an effect that a resist pattern having high rectangularity can be formed. The reason is not clear, but it is thought as follows.
The negative resist composition of the present invention comprises an alkali-soluble resin component having a specific proportion of the structural unit (a0) represented by the general formula (a0) in addition to the structural unit (a1) conventionally used. (A) is contained.
The structural unit (a1) exhibits phenolic acidity and has the effect of improving the alkali solubility of the component (A). However, in the crosslinking with the crosslinking agent component (C) at the time of exposure, the alkyl group of the fluorinated hydroxyalkyl group becomes a steric hindrance, and the hydroxy group and the component (C) cannot be sufficiently crosslinked.
On the other hand, the structural unit (a0), like the structural unit (a1), exhibits phenolic acidity and has the effect of improving the alkali solubility of the component (A). Further, in crosslinking with the component (C), there are few steric hindrances as in the structural unit (a1), and the component (C) can be crosslinked well. Therefore, the crosslink density in the exposed area is increased, and the alkali insolubility of the resist composition in the exposed area is further increased. In addition, since the structural unit (a0) has a naphthyl group, it has high transparency with respect to the exposure wavelength band (particularly the wavelength band of ArF excimer laser).
Therefore, it is estimated that the negative resist composition of the present invention can form a resist pattern with high rectangularity.

In addition, in the present invention, an effect that lithography characteristics such as reduction of line width roughness (LWR) are good is also obtained.
“LWR” represents a phenomenon in which the line width of a line pattern becomes non-uniform when a resist pattern is formed using a resist composition.
Moreover, in this invention, the effect that the alkali dissolution rate improves is also acquired.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention includes a step of forming a resist film on a support using the negative resist composition of the present invention, a step of exposing the resist film, and developing the resist film to form a resist pattern. It is a method including the process of forming.

  In such a resist pattern forming method, the support is not particularly limited, and a conventionally known one can be used, for example, a substrate for an electronic component or a substrate on which a predetermined wiring pattern is formed. can do. More specifically, a silicon wafer, 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.

The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the negative resist composition of the present invention is applied onto a substrate such as a silicon wafer with a spinner or the like, and pre-baking (post-apply baking (PAB)) is performed at a temperature of 80 to 150 ° C. for 40 to 120. Second, preferably 60 to 90 seconds, and selectively exposed to ArF excimer laser light through a desired mask pattern using, for example, an ArF exposure apparatus, and then subjected to PEB (exposure) at a temperature of 80 to 150 ° C. Post-heating) is performed for 40 to 120 seconds, preferably 60 to 90 seconds. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide. In this way, a resist pattern faithful to the mask pattern can be obtained.
An organic or inorganic antireflection film can be provided between the substrate and the coating layer of the resist composition.
The wavelength used for 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 Or the like. The negative resist composition according to the present invention is particularly effective for an ArF excimer laser.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

<Resin component (A)>
In the following examples and comparative examples, the resins (A) -1 to (A) -4 used as the component (A) were synthesized by the following synthesis examples using the following monomers (1) to (4). Obtained.

(Synthesis Example 1)
6.89 g of monomer (1), 0.878 g of monomer (2), and 3.00 g of monomer (3), dimethyl azobisisobutyrate (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator ) 0.30 g was dissolved in 100 mL of tetrahydrofuran (THF).
Next, 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 this reaction liquid with an evaporator, the concentrated liquid was dissolved in 120 mL of THF, and poured into 1000 mL of heptane to precipitate a resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain a white solid. And the said white solid was made into resin (A) -1.

(Synthesis Example 2)
6.56 g of monomer (1), 0.84 g of monomer (2), 2.85 g of monomer (3), and 0.43 g of monomer (4), dimethyl azobisisobutyrate (trade name: V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) 0.30 g was dissolved in tetrahydrofuran (THF) 90 mL.
Next, 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 this reaction liquid with an evaporator, the concentrated liquid was dissolved in 120 mL of THF, and poured into 1000 mL of heptane to precipitate a resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain a white solid. And the said white solid was made into resin (A) -2.

(Synthesis Example 3)
6.21 g of monomer (1), 0.79 g of monomer (2), 2.70 g of monomer (3), and 0.87 g of monomer (4), dimethyl azobisisobutyrate (trade name: V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) 0.30 g was dissolved in tetrahydrofuran (THF) 75 mL.
Next, 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 this reaction liquid with an evaporator, the concentrated liquid was dissolved in 120 mL of THF, and poured into 1000 mL of heptane to precipitate a resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain a white solid. And the said white solid was made into resin (A) -3.

(Synthesis Example 4)
5.52 g of monomer (1), 0.70 g of monomer (2), 2.40 g of monomer (3) and 1.74 g of monomer (4), dimethyl azobisisobutyrate (trade name: V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) 0.30 g was dissolved in tetrahydrofuran (THF) 50 mL.
Next, 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 this reaction liquid with an evaporator, the concentrated liquid was dissolved in 120 mL of THF, and poured into 1000 mL of heptane to precipitate a resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain a white solid. And the said white solid was made into resin (A) -4.

The structures of the obtained resins (A) -1 to (A) -4 are shown below.
Resins (A) -1 to (A) -4 are resins having structural units derived from the monomers (1) to (4) at different ratios. In the formula, “a0, a1, a2, a3” attached to the lower right of () is the ratio of each constituent unit to the total of all constituent units constituting each resin (composition ratio: mol%). Indicates.
Table 1 shows the mass average molecular weight (Mw), dispersity (Mw / Mn), and composition ratio (molar ratio) of each resin.
The mass average molecular weight (Mw) and dispersity (Mw / Mn) were determined on a polystyrene conversion basis by gel permeation chromatography (GPC). The proportion of each structural unit (composition ratio; mol%) was calculated by carbon NMR.

<Preparation of negative resist composition>
Each component shown in Table 2 was mixed and dissolved to prepare a negative resist composition.

Each abbreviation in Table 2 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(B) -1: Triphenylsulfonium trifluoromethanesulfonate.
(C) -1: Tetramethoxymethylated glycoluril MX270 (product name, manufactured by Sanwa Chemical Co., Ltd.).
(D) -1: Triisopropanolamine.
(S) -1: PGME.

  The lithography characteristics shown below were evaluated using the obtained negative resist composition.

<Evaluation of lithography properties>
First, an organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science) is uniformly applied on a silicon wafer using a spinner, and baked on a hot plate at 215 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a thickness of 30 nm was formed.
The negative resist compositions of Examples 1 and 2 and Comparative Examples 1 and 2 were uniformly coated on the organic antireflection film using a spinner, and prebaked at 80 ° C. for 60 seconds on a hot plate. By performing (PAB) treatment, a resist film having a thickness of 200 nm was formed.
Next, an ArF excimer laser (193 nm) was applied to the resist film by an ArF exposure apparatus NSR-S302 (product name, manufactured by Nikon; NA (numerical aperture) = 0.60, 2/3 annular illumination). It was selectively exposed through a mask pattern (halftone).
Then, a post-exposure heating (PEB) treatment is performed at 100 ° C. for 60 seconds, followed by development with an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution at 23 ° C. for 60 seconds, followed by washing with water for 30 seconds and drying. Thus, a line-and-space (1: 1) resist pattern (L / S pattern) is formed, and an optimal exposure amount (sensitivity: Eop, mJ / cm ² ) for forming an L / S pattern having a line width of 120 nm and a pitch of 240 nm. )

(Resist pattern shape)
In the above Eop, the size of the mask pattern was changed, and the shapes of the formed L / S patterns with line widths of 140 nm, 130 nm, and 120 nm were observed and evaluated with a scanning electron microscope (SEM). The results are shown in Table 3.

  From the results in Table 3, it was confirmed that Examples 1 and 2 according to the present invention can form a resist pattern having high rectangularity.

Claims (6)

A negative resist composition comprising an alkali-soluble resin component (A), an acid generator component (B) that generates acid upon exposure, and a crosslinking agent component (C),
The alkali-soluble resin component (A) is a structural unit (a0) represented by the following general formula (a0) with respect to the total of all the structural units constituting the alkali-soluble resin component (A). A negative resist composition comprising 10 mol% and having a structural unit containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group.

In the formula, R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹ and R ² each represents a lower alkyl group or an alkoxy group; n ¹ is 0-2 is an integer, ^{n 2} is an integer of 0 to 3, p is an integer of 1 to 3. ]   The negative resist composition according to claim 1, wherein the alkali-soluble resin component (A) further comprises a structural unit derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group.   The negative resist according to claim 1, wherein the alkali-soluble resin component (A) further has a structural unit that does not have a cyclic structure and is derived from acrylic acid having an alcoholic hydroxyl group in the side chain. Composition.   The crosslinking agent component (C) is at least one selected from the group consisting of a melamine crosslinking agent, a urea crosslinking agent, an alkylene urea crosslinking agent, a glycoluril crosslinking agent and an epoxy crosslinking agent. The negative resist composition as described in any one of 3.   Furthermore, the negative resist composition as described in any one of Claims 1-4 containing a nitrogen-containing organic compound (D).   A step of forming a resist film on a support using the negative resist composition according to any one of claims 1 to 5, a step of exposing the resist film, and developing the resist film to form a resist pattern A method for forming a resist pattern comprising the step of forming