JP2005336452A - Resin for resist composition, negative type resist composition and method for forming resist pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for suppressing swelling of a resist pattern. <P>SOLUTION: A negative type resist composition is obtained by using a resin for the resist composition having a constituent unit (a1) containing an alicyclic group having a fluorinated hydroxyalkyl group and a constituent unit (a2) derived from an acrylic ester and containing a hydroxy group-containing alicyclic group. The resist pattern is formed by using the resist composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  Conventional negative resist compositions used in processes using i-line or KrF excimer laser light (248 nm) as light sources include acid generators, alkali-soluble resins such as novolac resins and polyhydroxystyrene, melamine resins and urea resins, etc. A chemically amplified negative resist containing a combination with an amino resin is used (for example, Patent Document 1).

Further, as a negative resist composition applied to a process using an ArF excimer laser having a shorter wavelength, the resin composition having a carboxyl group, for example, a crosslink having an alcoholic hydroxyl group is improved in transparency to the ArF excimer laser. A negative resist composition containing an agent 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 carboxyl 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 carboxyl group or carboxylic acid ester group and an alcoholic hydroxyl group, respectively, and an acid generator, wherein the carboxyl 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 3, patents). Literature 2 etc.).
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, any of the negative resist compositions developed for conventional ArF excimer lasers has a problem that resist pattern swelling cannot be sufficiently suppressed. The swelling of the resist pattern is a very important problem in a process for forming a fine pattern such as using a KrF excimer laser, an ArF excimer laser or the like.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the technique which can suppress swelling of a resist pattern.

In order to achieve the above object, the present invention employs the following configuration.
The resin for resist compositions of the present invention is a structural unit (a1) containing an alicyclic group having a fluorinated hydroxyalkyl group and a structural unit derived from an acrylate ester, the hydroxyl group-containing alicyclic ring And a structural unit (a2) containing a formula group.
The negative resist composition of the present invention comprises (A) a resin for a resist composition of the present invention, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component. To do.
In the resist pattern forming method of the present invention, the negative resist composition of the present invention is coated on a substrate, pre-baked, selectively exposed, subjected to PEB (post-exposure heating), and alkali-developed. A resist pattern is formed.
The “constituent unit” refers to a monomer unit constituting a polymer (resin).
“Structural unit derived from acrylic acid” means a structural unit formed by cleavage of an ethylenic double bond of acrylic acid.
The “structural unit derived from an acrylate ester” means a structural unit constituted by cleavage of an ethylenic double bond of an acrylate ester.
The “structural unit derived from an acrylate ester” has a concept including those in which the hydrogen atom at the α-position is substituted with another substituent such as an alkyl group. In the “structural unit derived from acrylic acid” and the “structural unit derived from acrylate ester”, the term “α-position (α-position carbon atom)” means that unless otherwise specified, the carboxyl group is It is a bonded carbon atom.
The “structural unit derived from acrylic acid” is a structural unit in which the hydrogen atom bonded to the α-position carbon atom is substituted with another substituent such as an alkyl group, or a hydrogen atom in the α-position carbon atom. The concept includes a structural unit derived from a bonded acrylate ester.
In the claims or the specification, the “alkyl group” includes a linear, cyclic, or branched alkyl group unless otherwise specified.
In addition, “exposure” is a concept that encompasses not only light irradiation but also entire irradiation of radiation such as electron beam irradiation.

  In the present invention, a technique capable of suppressing swelling of a resist pattern can be provided.

[Resist composition resin]
The resin for resist compositions of the present invention is a structural unit (a1) containing an alicyclic group having a fluorinated hydroxyalkyl group and a structural unit derived from an acrylate ester, the hydroxyl group-containing alicyclic ring And a structural unit (a2) containing a formula group.

Structural unit (a1) containing an alicyclic group having a fluorinated hydroxyalkyl group
In the resin for resist compositions of the present invention, the swelling suppression effect is improved by having the structural unit (a1).

-Alicyclic group which has a fluorinated hydroxyalkyl group In a structural unit (a1), an alicyclic group has a fluorinated hydroxyalkyl group.
The fluorinated hydroxyalkyl group is an alkyl group having a hydroxy group in which part or all of the hydrogen atoms of the alkyl group are substituted with fluorine. In the group, the hydrogen atom of the hydroxyl group is easily liberated by fluorination.
In the fluorinated hydroxyalkyl group, the alkyl group is linear or branched, and the number of carbon atoms is not particularly limited, but is, for example, 1 to 20, preferably 4 to 16. The number of hydroxyl groups is not particularly limited, but is usually one.
In particular, in the alkyl group, a fluorinated alkyl group and / or a fluorine atom is bonded to the α-position carbon atom to which the hydroxy group is bonded (in this case, the α-position carbon atom of the hydroxyalkyl group). Those are preferred. 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.

  The alicyclic group may be monocyclic or polycyclic, but is preferably a polycyclic group. Moreover, an alicyclic hydrocarbon group is preferable. Moreover, it is preferable that it is saturated. Moreover, it is preferable that carbon number of an alicyclic group is 5-15.

Specific examples of the alicyclic group include the following.
That is, examples of the monocyclic group include groups in which one hydrogen atom has been removed from a cycloalkane. Examples of the polycyclic group include groups in which one or two hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane or the like.
More specifically, examples of the monocyclic group include groups in which one or two hydrogen atoms have been removed from cyclopentane or cyclohexane, and two hydrogen atoms have been removed from cyclohexane.
Examples of the polycyclic group include groups in which one or two hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane.
Such a polycyclic group is appropriately selected from among many that have been proposed as constituting an acid dissociable, dissolution inhibiting group in a resin for a positive photoresist composition for ArF excimer laser process, for example. 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 acrylic acid, and has a structure (carboxyl group) in which the alicyclic group is bonded to the ester group [—C (O) O—] of the acrylate ester. A structure in which a hydrogen atom is substituted with the alicyclic group is preferred.

  As the structural unit (a1), more specifically, those represented by the following general formula (1) are preferred.

（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。）

(In the formula, R is 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.
N, m, and p are each preferably 1.

  Among those represented by the general formula (1), α, α′-bis- (trifluoromethyl) -bicyclo [2.2.1] hept-5-ene-2-ethanol acrylate (in the following [Chemical Formula 7] The structural unit derived from the monomer shown) is preferable from the standpoint of effects, easy synthesis, and high etching resistance.

  The structural unit (a1) can be used alone or in combination of two or more.

A structural unit derived from an acrylate ester and containing a hydroxyl group-containing alicyclic group (a2)
In the resin for resist compositions, the effect of suppressing swelling is improved by including the structural unit (a2). Moreover, the effect of improving etching resistance can be obtained.
When the resin for a resist composition of the present invention is blended into a negative resist composition, the hydroxyl group (alcoholic hydroxyl group) of the structural unit (a2) is converted into (C) by the action of an acid generated from (B) an acid generator. It reacts with a cross-linking agent, whereby the resin for resist composition is changed from a property soluble in an alkali developer to an insoluble property.

  In the structural unit (a2), the hydroxyl group-containing alicyclic group is preferably bonded to the ester group (—C (O) O—) of the acrylate ester.

In the structural unit (a2), another substituent may be bonded to the α-position (α-position carbon atom) instead of a hydrogen atom. The substituent is preferably an alkyl group, a fluorinated alkyl group, or a fluorine atom.
These explanations are the same as those of R in the general formula (1) of the structural unit (a1), and among those which can be bonded to the α-position, a hydrogen atom or an alkyl group is preferred, An atom or a methyl group is preferred, and a hydrogen atom is most preferred.

The hydroxyl group-containing alicyclic group is a group in which a hydroxyl group is bonded to the alicyclic group.
It is preferable that 1-3 hydroxyl groups are couple | bonded, for example, More preferably, it is one.
Moreover, the C1-C4 alkyl group may couple | bond with the alicyclic group.

  Here, the alicyclic group may be monocyclic or polycyclic, but is preferably a polycyclic group. Moreover, an alicyclic hydrocarbon group is preferable. Moreover, it is preferable that it is saturated. Moreover, it is preferable that carbon number of an alicyclic group is 5-15.

Specific examples of the alicyclic group include the following.
That is, examples of the monocyclic group include groups in which one hydrogen atom has been removed from a cycloalkane. Examples of the polycyclic group include groups in which one hydrogen atom has been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like.
More specifically, examples of the monocyclic group include groups in which one hydrogen atom has been removed from cyclopentane or cyclohexane, and a cyclohexyl group is preferred.
Examples of the polycyclic group include groups in which one hydrogen atom has been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
Such a polycyclic group is appropriately selected from among many that have been proposed as constituting an acid dissociable, dissolution inhibiting group in a resin for a positive photoresist composition for ArF excimer laser process, for example. Can be used.
Among these, a cyclohexyl group, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are preferable because they are easily available on the industry.
Among these exemplified monocyclic groups and polycyclic groups, a cyclohexyl group and an adamantyl group are preferable, and an adamantyl group is particularly preferable.

  As a specific example of the structural unit (a2), for example, a structural unit represented by the following general formula (2) is preferable.

（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、ｑは１〜３の整数である。）

(R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom, and q is an integer of 1 to 3.)

R is a hydrogen atom, an alkyl group, a fluorinated alkyl group, or a fluorine atom bonded to the α-position, and is the same as described in the general formula (1). In the general formula (2), R is most preferably a hydrogen atom.
Moreover, q is an integer of 1 to 3, but is preferably 1.
Further, the bonding position of the hydroxyl group is not particularly limited, but it is preferably bonded to the position of the 3rd position of the adamantyl group.

  As the structural unit (a2), one type or a mixture of two or more types can be used.

A structural unit derived from acrylic acid and having no cyclic structure, the structural unit having an alcoholic hydroxyl group in the side chain (a3)
The resin for a resist composition of the present invention preferably has a structural unit (a3) in addition to the structural unit (a1) and the structural unit (a2).
By having the structural unit (a3), the 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.

“No cyclic structure” means having no alicyclic group or aromatic group.
The structural unit (a3) is clearly distinguished from the structural unit (a2) by not having a cyclic structure. When a resin for a resist composition having the structural unit (a3) is blended in a negative resist composition, the hydroxyl group of the hydroxyalkyl group of the structural unit (a3) together with the hydroxyl group of the structural unit (a2) becomes (B) By the action of the acid generated from the acid generator, it reacts with the (C) crosslinking agent, whereby the resin for a resist composition changes from a property soluble in an alkali developer to an insoluble property.

“Having an alcoholic hydroxyl group in the side chain” includes, for example, a structural unit to which a hydroxyalkyl group is bonded.
The hydroxyalkyl group may be bonded to the α-position carbon atom of the main chain (the portion where the ethylenic double bond of acrylic acid is cleaved), or substituted with a hydrogen atom of the carboxyl group of acrylic acid to form an ester. In the structural unit (a3), it is preferable that at least one or both of them be present.

  When a hydroxyalkyl group is not bonded to the α-position, an alkyl group, a fluorinated alkyl group, or a fluorine atom may be bonded to the α-position carbon atom instead of a hydrogen atom. These are the same as the description of R in the general formula (1).

  The structural unit (a3) is preferably one represented by the following general formula (3).

（式中、Ｒ^１は水素原子、アルキル基、フッ素化アルキル基、フッ素原子またはヒドロキシアルキル基であり、Ｒ^２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り、かつＲ^１、Ｒ^２の少なくとも一方はヒドロキシアルキル基である。）

Wherein R ¹ is a hydrogen atom, an alkyl group, a fluorinated alkyl group, a fluorine atom or a hydroxyalkyl group, R ² is a hydrogen atom, an alkyl group or a hydroxyalkyl group, and R ¹ , R ² At least one of them is a hydroxyalkyl group.)

In R ¹ , the hydroxyalkyl group is preferably a lower hydroxyalkyl group having 10 or less carbon atoms, more preferably a lower hydroxyalkyl group having 2 to 8 carbon atoms, and most preferably a hydroxymethyl group or a hydroxyethyl group. It is. The number of hydroxyl groups and the bonding position are not particularly limited, but it is usually one and preferably bonded to the end of the alkyl group.
In R ¹ , the alkyl group is preferably a lower alkyl group having 10 or less carbon atoms, more preferably a lower alkyl group having 2 to 8 carbon atoms, and most preferably an ethyl group or a methyl group.
In R ¹ , the fluorinated alkyl group is preferably a lower alkyl group having 5 or less carbon atoms (preferably an ethyl group or a methyl group) in which part or all of the hydrogen atoms are substituted with fluorine.
In R ² , the alkyl group and the hydroxyalkyl group are the same as R ¹ .

Specifically, structural units derived from α- (hydroxyalkyl) acrylic acid, structural units derived from α- (hydroxyalkyl) acrylic acid alkyl ester, and (α-alkyl) acrylic acid hydroxyalkyl ester. Structural units.
Especially, it is preferable that a structural unit (a3) contains the structural unit induced | guided | derived from alpha- (hydroxyalkyl) acrylic acid alkyl ester from the point of an effect improvement and a film density improvement. Among them, a structural unit derived from α- (hydroxymethyl) -acrylic acid ethyl ester or α- (hydroxymethyl) -acrylic acid methyl ester is preferable.
Moreover, it is preferable that the structural unit (a3) includes a structural unit derived from (α-alkyl) acrylic acid hydroxyalkyl ester. Among them, a structural unit derived from α-methyl-acrylic acid hydroxyethyl ester or α-methyl-acrylic acid hydroxymethyl ester is preferable.

  The structural unit (a3) can be used alone or in combination of two or more.

Structural unit (a4) derived from an acrylate ester containing a lactone-containing monocyclic or polycyclic group
In the present invention, in addition to the structural unit (a1) and the structural unit (a2), the structural unit (a4) may be derived from an acrylate ester containing a lactone-containing monocyclic or polycyclic group. preferable.
In addition to the structural unit (a1), the structural unit (a2), and the structural unit (a4), the structural unit (a3) may be further combined.

  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.

  In addition, lactone here shows one ring containing -O-C (O)-structure, and this is counted as one 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.

  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. is there.

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.

  In the structural unit (a4), those having a lactone-containing polycyclic group are preferred, and those having norbornane lactone are preferred.

In the structural unit (a4), another substituent group may be bonded to the α-position (α-position carbon atom) instead of a hydrogen atom. The substituent is preferably an alkyl group, a fluorinated alkyl group, or a fluorine atom.
These explanations are the same as those of R in the general formula (1) of the structural unit (a1), and among those which can be bonded to the α-position, a hydrogen atom or an alkyl group is preferred, An atom or a methyl group is preferred, and a hydrogen atom is most 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。）

(In the formula, R is the same as described 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 the structural unit (a1). In general formulas (a4-1) to (a4-5), R ′ is preferably a hydrogen atom in view of industrial availability.

 And as a structural unit (a4), the unit represented by general formula (a4-2)-(a4-3) is the most preferable.

  As the structural unit (a4), one type may be used alone, or two or more types may be used in combination.

Combination of Structural Unit (a1) to Structural Unit (a4) In the present invention, the structural unit (a1) to structural unit (a4) are preferably selected from, for example, four types of combinations as follows.

(A) Select so as to include a combination of the structural unit (a1) and the structural unit (a2).
At this time, it is preferable that the structural unit (a1) is a structural unit represented by the general formula (1), and R in the general formula (1) is a hydrogen atom. At the same time, a hydrogen atom is preferably bonded to the α position (carbon atom to which the carboxyl group is bonded) of the structural unit (a2). The reason is that the dissolution contrast becomes good.

(B) Selection is made so as to include a combination of the structural unit (a1), the structural unit (a2), and the structural unit (a3).
At this time, it is preferable that the structural unit (a1) is a structural unit represented by the general formula (1), and R in the general formula (1) is a hydrogen atom. At the same time, a hydrogen atom is preferably bonded to the α-position of the structural unit (a2). The reason is that the dissolution contrast becomes good.

(C) Selection is made so as to include a combination of the structural unit (a1), the structural unit (a2), and the structural unit (a4).
At this time, it is preferable that the structural unit (a1) is a structural unit represented by the general formula (1), and R in the general formula (1) is a hydrogen atom. At the same time, it is preferable that a hydrogen atom is bonded to the α-position of the structural unit (a2) and a hydrogen atom is bonded to the α-position of the structural unit (a4).
The reason is that the dissolution contrast becomes good.

(D) Selection is made so as to include a combination of the structural unit (a1), the structural unit (a2), the structural unit (a3), and the structural unit (a4).
At this time, it is preferable that the structural unit (a1) is a structural unit represented by the general formula (1), and R in the general formula (1) is a hydrogen atom. At the same time, it is preferable that a hydrogen atom is bonded to the α-position of the structural unit (a2) and a hydrogen atom is bonded to the α-position of the structural unit (a4).
The reason is that the dissolution contrast becomes good.

Ratio of Structural Unit (a1) to Structural Unit (a4) In the present invention, in combining the structural units (a1) to (a4), as described above, (A), (B), (C), (C) It is preferable to select four types of combinations classified into d). Then, about these, the ratio of each preferable structural unit is shown below, respectively.
(A) Combination of structural unit (a1) and structural unit (a2) At least two of structural unit (a1) and structural unit (a2) are essential, and preferably a resin comprising these two structural units, It is preferable that the ratio of each structural unit in it satisfies the following numerical ranges.
That is, the proportion of the structural unit (a1) is preferably 20 to 80 mol%, more preferably 30 to 70 mol%, and most preferably 35 to 55 mol%.
The proportion of the structural unit (a2) is preferably 20 to 80 mol%, more preferably 30 to 7
0 mol%, most preferably 35-55 mol%.
By satisfying these ranges, the effect of suppressing swelling is improved.

(B) Combination of structural unit (a1), structural unit (a2), and structural unit (a3) A resin having structural unit (a1), structural unit (a2), and structural unit (a3), preferably these In the case of a resin comprising the following structural units, the proportion of each structural unit in the resin preferably satisfies the following numerical range.
That is, the proportion of the structural unit (a1) is preferably 20 to 80 mol%, more preferably 30 to 70 mol%, and most preferably 35 to 55 mol%.
The proportion of the structural unit (a2) is preferably 10 to 70 mol%, more preferably 10 to 50 mol.
It is mol%, More preferably, it is 20-40 mol%.
The proportion of the structural unit (a3) is preferably 10 to 70 mol%, more preferably 10 to 4
0 mol%, most preferably 15-35 mol%.
By satisfying these ranges, the effect of suppressing swelling is improved. In particular, by blending the structural unit (a2) and the structural unit (a3) in a well-balanced manner, an appropriate contrast can be obtained and resolution can be improved. In addition, etching resistance is improved. Furthermore, a good exposure margin can be obtained.

(C) Combination of structural unit (a1), structural unit (a2), and structural unit (a4) A resin having structural units (a1), (a2), and (a4), and preferably a resin comprising these structural units In this case, the proportion of each structural unit in the resin preferably satisfies the following numerical range.
That is, the proportion of the structural unit (a1) is preferably 20 to 85 mol%, more preferably 30 to 70 mol%, and most preferably 35 to 50 mol%.
The proportion of the structural unit (a2) is preferably 14 to 70 mol%, more preferably 15 to 50.
It is mol%, Most preferably, it is 30-50 mol%.
The proportion of the structural unit (a4) is preferably 1 to 70 mol%, more preferably 3 to 50 mol%, and most preferably 5 to 20 mol%.
By satisfying these ranges, the effect of suppressing swelling is improved. Further, the resist pattern shape is improved.
Further, by blending (a1), (a2), and (a4) in a balanced manner, an appropriate contrast can be obtained and the resolution is improved. In addition, etching resistance is improved. Furthermore, a good exposure margin can be obtained.

(D) A combination of the structural unit (a1), the structural unit (a2), the structural unit (a3), and the structural unit (a4) is a resin having all of the structural units (a1) to (a4), preferably these In the case of a resin comprising the following structural units, the proportion of each structural unit in the resin preferably satisfies the following numerical range.
That is, the proportion of the structural unit (a1) is preferably 10 to 85 mol%, more preferably 20 to 70 mol%, and most preferably 25 to 50 mol%.
The proportion of the structural unit (a2) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, and most preferably 30 to 50 mol%.
The proportion of the structural unit (a3) is preferably 4 to 70 mol%, more preferably 7 to 50 mol%, and most preferably 10 to 30 mol%.
The proportion of the structural unit (a4) is preferably 1 to 70 mol%, more preferably 3 to 50 mol%, and most preferably 5 to 20 mol%.
By satisfying these ranges, the effect of suppressing swelling is further improved. Further, the resist pattern shape is improved.
Further, by blending the structural unit (a1) to the structural unit (a4) in a balanced manner, an appropriate contrast can be obtained and resolution can be improved. In addition, etching resistance is improved. Furthermore, a good exposure margin can be obtained.

The resin for resist compositions may have other copolymerizable structural units other than those selected from the structural units (a1) to (a4), but the structural units (a1) to ( A resin having as a main component a structural unit selected from a4) is preferred.
Here, the main component is preferably a total of 70 mol% or more, preferably 80 mol% or more, preferably 100%, among the structural units selected from these.

  In the resist composition resin, particularly preferred is a resin comprising the structural unit (a1) and the structural unit (a2), or a resin comprising the structural unit (a1), the structural unit (a2) and the structural unit (a3). Or a resin comprising the structural unit (a1), the structural unit (a2) and the structural unit (a4), or a resin comprising the structural unit (a1) to the structural unit (a4), more preferably the structural unit (a1), It is a resin composed of the structural unit (a2) and the structural unit (a3).

Mass average molecular weight The mass average molecular weight (Mw; polystyrene-converted mass average molecular weight by gel permeation chromatography) of the resin for resist compositions is preferably 2000 to 30000, more preferably 2000 to 10000, and most preferably 3000 to 8000. . By setting it as this range, it is preferable from the point of suppression of swelling and the suppression of microbridge by this. Moreover, it is preferable from the point of high resolution. When the molecular weight is low, good characteristics tend to be obtained.

  The resin for resist composition can be obtained, for example, by radical polymerization of a monomer for deriving each structural unit by a conventional method.

  The resin for resist compositions of the present invention is suitable for use in negative resist compositions.

[Negative resist composition]
The negative resist composition of the present invention contains (A) a resin for a resist composition of the present invention, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component.

(A) Resin for Resist Composition of the Present Invention The component (A) is as described above.
(A) A component can be used 1 type or in mixture of 2 or more types.
What is necessary is just to adjust content of (A) component according to the resist film thickness to form.

(B) Acid generator component that generates acid by exposure The component (B) can be used without particular limitation from known acid generators used in conventional chemically amplified resist compositions.
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, Various kinds of acid generators such as diazomethane acid generators such as nitrobenzyl sulfonates, imino sulfonate acid generators and disulfone acid generators are known.
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 Le) trifluoromethanesulfonate triphenylsulfonium, its like heptafluoropropane sulfonate or nonafluorobutane sulfonates.

  Specific examples of the oxime sulfonate acid generator include α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoromethylsulfonyloxyimino)- Phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (propylsulfonyloxyimino) -p-methylphenylacetonitrile, α- (methylsulfonyloxyimino) -p-bromophenylacetonitrile and the like can be mentioned. Of these, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile is 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 (Compound A, decomposition point 135 ° C.), 1,4-bis (phenyl) having the following structure. Sulfonyldiazomethylsulfonyl) butane (compound B, decomposition point 147 ° C.), 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane (compound C, melting point 132 ° C., decomposition point 145 ° C.), 1,10-bis (phenyl) Sulfonyldiazomethylsulfonyl) decane (compound D, decomposition point 147 ° C.), 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane (compound E, decomposition point 149 ° C.), 1,3-bis (cyclohexylsulfonyldiazomethylsulfonyl) ) Propane (Compound F, decomposition point 153 ° C.), , 6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane (Compound G, melting point 109 ° C., decomposition point 122 ° C.), 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane (Compound H, decomposition point 116 ° C.), etc. Can be mentioned.

  In the present invention, from the viewpoint of the reactivity between the component (A) and the component (C), it is preferable to use an onium salt having a fluorinated alkyl sulfonate ion as an anion as the component (B).

As the component (B), one type of acid generator may be used alone, or two or more types may be used in combination.
(B) Content of a component is 0.5-30 mass parts with respect to 100 mass parts of (A) component, Preferably it is 1-10 mass parts. By setting it as the said range, pattern formation can fully be performed. Moreover, since a uniform resist solution is obtained and storage stability becomes favorable, it is preferable.

(C) Crosslinking agent component The (C) component is not particularly limited, and is arbitrarily selected from the crosslinking agent components used in the chemically amplified negative resist compositions known so far. be able to.

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, glycoluril are reacted with formaldehyde or formaldehyde and a lower alcohol, and the hydrogen atom of the amino group is replaced with a hydroxymethyl group or a lower alkoxymethyl group. Compounds.
Of these, those using melamine are melamine crosslinking agents, those using urea are urea crosslinking agents, those using ethylene urea are ethylene urea crosslinking agents, and those using glycoluril are glycoluril crosslinking agents It is called an agent.
Specific examples include hexamethoxymethylmelamine, bismethoxymethylurea, bismethoxymethylbismethoxyethyleneurea, tetramethoxymethylglycoluril, tetrabutoxymethylglycoluril and the like.

  The component (C) is particularly preferably at least one selected from melamine crosslinking agents, urea crosslinking agents, ethyleneurea crosslinking agents, and glycoluril crosslinking agents. Particularly preferred is a glycoluril-based crosslinking agent.

As the glycoluril-based crosslinking agent, glycoluril substituted at the N-position with a hydroxyalkyl group and / or a lower alkoxyalkyl group which is a crosslinking group is preferable.
More specifically, examples of the glycoluril-based crosslinking agent include mono-, di-, tri- and tetrahydroxymethyl glycolurils, mono-, di-, tri- and / or tetramethoxymethylated glycolurils, mono-, di-, tri- and / or tetra- Examples include ethoxymethyl glycoluril, mono, di, tri and / or tetrapropoxymethylated glycoluril, mono, di, tri and / or tetrabutoxymethylated glycoluril. "Mono, di, tri and / or tetra ..." indicates that one or more of mono-, di-, tri-, and tetra-forms may be included, particularly A tri- or tetra-isomer is preferred.
Mono, di, tri and / or tetramethoxymethylated glycoluril and mono, di, tri and / or tetrabutoxymethylated glycoluril are also preferred.
From the viewpoint of contrast and resolution, mono, di, tri and / or tetramethoxymethylated glycoluril is most preferable. This crosslinking agent can be obtained, for example, as a commercial product “Mx270” (product name, manufactured by Sanwa Chemical Co., Ltd.). These are mostly tri- and tetra-isomers, and are a mixture of monomers, dimers and trimers.

  (C) The compounding quantity of a component shall be 3-15 mass parts with respect to 100 mass parts of (A) component, Preferably it is 5-10 mass parts. By setting it to the lower limit value or more, the component (A) can be made insoluble in alkali. By setting the upper limit value or less, it is possible to prevent a decrease in resolution. The tendency that the resolution is improved when the addition amount of the crosslinking agent is small is characteristic in the negative resist composition of the present invention and is economically preferable.

(D) Nitrogen-containing organic compound In the negative resist composition of the present invention, a nitrogen-containing organic compound (D) (hereinafter, referred to as “optional”) is further added as an optional component in order to improve the resist pattern shape, the stability over time. (Referred to as component (D)).
Since a wide variety of components (D) have 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.
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. Among these, alkyl alcohol amines and trialkyl amines are preferable, and alkyl alcohol amines are most preferable. Of the alkyl alcohol amines, alkyl alcohol amines such as triethanolamine and triisopropanolamine are most preferred.

Component (E) In addition, for the purpose of preventing sensitivity deterioration due to the blending with the component (D) and improving the resist pattern shape, retention stability, etc., an organic carboxylic acid or phosphorus oxoacid is further included as an optional component. Or its derivative (E) (henceforth (E) component) 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 The negative resist composition of the present invention can be produced by dissolving the material in an organic solvent.
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 2: 8 to 8: 2, more preferably 3: 7 to 7: 3.
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.
In addition, propylene glycol monomethyl ether (PGME) is also preferable as the organic solvent.
Although the amount of the organic solvent used is not particularly limited, it 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 content concentration of the resist composition is 2 to 20 mass. %, Preferably 5-15% by mass.

Other optional components In the negative resist composition of the present invention, there are further miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving the coating properties, A dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

The negative resist composition of the present invention is not particularly limited, but is suitable for a process using an ArF excimer laser as an exposure light source.
The process requires high resolution, and in the negative resist composition of the present invention, various properties such as resolution are improved by suppressing swelling, and thus such severe demands are made. It is because it can respond to.
Moreover, it is because it can be set as a highly transparent structure with respect to an ArF excimer laser.

[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 (PAB), selectively exposed, PEB (post-exposure heating) is applied, and alkali development is performed. A resist pattern is formed.
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 such as a silicon wafer with a spinner or the like, and prebaked at 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 90 seconds. After selectively exposing ArF excimer laser light through a desired mask pattern using, for example, an ArF exposure apparatus or the like, PEB (post-exposure heating) is performed for 40 to 120 seconds at a temperature of 80 to 150 ° C., preferably Apply for 60-90 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 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 resist composition according to the present invention is effective for an ArF excimer laser as described above.

In the present invention, swelling of the resist pattern can be prevented. Thereby, a microbridge can be suppressed. Also, the resolution is good. In addition, the depth-of-focus characteristic is improved. Moreover, LER (line edge roughness) can be suppressed. Note that LER is uneven unevenness of the line side wall.
Moreover, the effect that stability with time improves is also obtained.

[Monomer used in synthesis example]
In the synthesis examples, the following monomers were used.
(I) NBHFAA (norbornene hexafluoroalcohol acrylate) represented by the following chemical formula, molecular weight 340

(Ii) HEMA (hydroxyethyl methacrylate) represented by the following chemical formula, molecular weight 1
30

(Iii) AdOHA (adamantanol acrylate) represented by the following chemical formula, molecular weight 2
22

(Iv) RHMA-E [(α-hydroxymethyl) ethyl acrylate] represented by the following chemical formula, molecular weight 130

(V) RHMA-M [(α-hydroxymethyl) methyl acrylate] represented by the following chemical formula, molecular weight 116

（vi）下記化学式で表されるＧＢＬＡ（γ―ブチロラクトンアクリレート）、分子量１１６

(Vi) GBLA (γ-butyrolactone acrylate) represented by the following chemical formula, molecular weight 116

（vii）下記化学式で表されるＮＢＬＡ（ノルボルナンラクトンアクリレート）、分子量２２２

(Vii) NBLA (norbornane lactone acrylate) represented by the following chemical formula, molecular weight 222

[Synthesis example]
In this synthesis example, NMR was measured using JNM-AL400 (product name, resolution 400 MHz) manufactured by JEOL Ltd.
Synthesis example 1
9.19 g of NBHFAA, 3.51 g of HEMA, and 6.0 g of AdOHA 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 the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 15.6 g of a white solid (yield 83.4%).
The obtained resin is represented by the following chemical formula (4). The mass average molecular weight (Mw) was 14400, and dispersity (Mw / Mn; Mw was a mass average molecular weight, Mn was a number average molecular weight) was 1.86.
When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 33/33/33. This is Resin 1.

Synthesis example 2
NBHFAA 13.58 g, HEMA 3.51 g, AdOHA 6.0 g, and 0.7 g of azobisisoacetate dimethyl 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 the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 21.1 g of a white solid (yield 91.4%).
The chemical formula of the obtained resin is the same as the chemical formula (4). Its mass average molecular weight (Mw) was 18200, and dispersity (Mw / Mn) was 2.20. When confirmed with carbon NMR, composition ratio (mol%) was 1 / m / n = 42.5 / 28.75 / 28.75. This is Resin 2.

Synthesis example 3
NBHFAA 17.58 g, HEMA 3.51 g, AdOHA 6.0 g, and azobisisoacetate dimethyl 0.87 g were dissolved in THF (tetrahydrofuran) 200 ml. 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 the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 23.9 g of a white solid (yield 88.2%).
The chemical formula of the obtained resin is the same as the chemical formula (4). Its mass average molecular weight (Mw) was 17400, and dispersity (Mw / Mn) was 2.40. When confirmed with carbon NMR, composition ratio (mol%) was 1 / m / n = 49 / 25.5 / 25.5. This is designated as resin 3.

Synthesis example 4
13.58 g of NBHFAA, 1.76 g of HEMA, and 6.0 g of AdOHA 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 the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 18.8 g of a white solid (yield 88.0%).
The chemical formula of the obtained resin is the same as the chemical formula (4). Its mass average molecular weight (Mw) was 5900, and dispersity (Mw / Mn) was 1.98. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 50/17/33. This is designated as Resin 4.

Synthesis example 5
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 the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 14.1 g of a white solid (yield 72.0%).
The chemical formula of the obtained resin is chemical formula (5). 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. This is designated as resin 5 (decomposition point: 293 ° C., Tg: 105 ° C.).

Synthesis example 6
13.3 g of NBHFAA, 3.51 g of HEMA, and 6.0 g of AdOHA, and 0.7 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 the resin, followed by filtration.
The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 19.8 g of a white solid (yield 86.8%).
The chemical formula of the obtained resin is the same as the chemical formula (4). The mass mean molecular weight (Mw) was 5500, and dispersion degree (Mw / Mn) was 1.90. When confirmed with carbon NMR, composition ratio (mol%) was 1 / m / n = 39.9 / 29.4 / 30.7. This is designated as Resin 6. The results of proton nuclear magnetic resonance spectrum ( ¹ H-NMR) and infrared absorption spectrum (IR) were as follows.
IR (cm ⁻¹ ): 3350 (—OH), 2951 (—CH ₂ CH ₃ —), 1730 (C═O), 1456 (
-CH _2- ), 1072 (C-OH)
¹ H-NMR (DMSO-d ₆ , internal standard: tetramethylsilane) ppm: 1 to 2.3 (
m, 36H), 3.5 (s, 2H), 3.9 (s, 2H), 4.4 to 4.8 (m, 3H)
7.7 (d, 1H)
Decomposition point: 225 ° C
Tg: 102 ° C

Synthesis example 7
NBHFAA 7.87 g, HEMA 3.51 g and AdOHA 6.0 g, and azobisisoacetate dimethyl 0.58 g as a polymerization initiator were dissolved in THF (tetrahydrofuran) 200 ml. 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 the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 14.9 g of a white solid (yield 85.7%).
The chemical formula of the obtained resin is the same as the chemical formula (4). Its mass average molecular weight (Mw) was 6500, and dispersity (Mw / Mn) was 2.23. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 30/35/35. This is designated as Resin 7.

Synthesis example 8
13.3 g of NBHFAA, 3.51 g of RHMA-E and 6.0 g of AdOHA, and 0.7 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 the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 21.0 g of a white solid (yield 92.0%).
The chemical formula of the obtained resin is the following chemical formula (6). Its mass average molecular weight (Mw) was 5570 and dispersity (Mw / Mn) was 2.02. When confirmed with carbon NMR, composition ratio (mol%) was 1 / m / n = 35.8 / 26.3 / 37.9. This is designated as Resin 8.
The results of proton nuclear magnetic resonance spectrum ( ¹ H-NMR) and infrared absorption spectrum (IR) were as follows.
IR (cm ⁻¹ ): 3388 (—OH), 2948 (—CH ₂ CH ₃ —), 1730 (C═O), 1452 (—CH ₂ —), 1052 (C—OH)
¹ H-NMR (DMSO, internal standard: tetramethylsilane) ppm: 1 to 2.3 (m, 36H), 3.5 (Broad, 2H), 4.0 (s, 2H), 4.4 to 4 .8 (d, 3H), 7.7 (d, 1H)
Decomposition point: 238 ° C
Tg: 94 ° C

Synthesis example 9
9.50 g of NBHFAA, 1.21 g of HEMA, and 2.07 g of AdOHA, and 0.35 g of dimethyl azobisisoacetate as a polymerization initiator were dissolved in 100 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 60 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 11.5 g of a white solid (yield 90.0%).
The chemical formula of the obtained resin is the same as the chemical formula (4). Its mass average molecular weight (Mw) was 6600, and dispersity (Mw / Mn) was 2.15. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 60/20/20. This is designated as resin 9.

Synthesis example 10
12.66 g of NBHFAA, 0.6 g of HEMA, and 1.03 g of AdOHA, and 0.35 g of dimethyl azobisisoacetate as a polymerization initiator were dissolved in 100 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 60 ml of THF, and poured into 2000 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 10.63 g of a white solid (yield 74.3%).
The chemical formula of the obtained resin is the same as the chemical formula (4). Its mass average molecular weight (Mw) was 6100, and dispersity (Mw / Mn) was 1.52. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 80/10/10. This is designated as resin 10.

Synthesis example 11
30.0 g of NBHFAA and 0.70 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 dioxane, and poured into 4800 ml of pure water to precipitate a resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 10.64 g of a white solid (yield 53.2%).
The chemical formula of the obtained resin is as the following chemical formula (7). Its mass average molecular weight (Mw)
Was 3800, and the dispersity (Mw / Mn) was 1.37. This is designated as resin 11.

Synthesis example 12
2.73 g of methacrylic acid, 16.5 g of RHMA-E and 1.0 g of azobisisobutyronitrile as a polymerization initiator were dissolved in 300 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 150 ml of THF and poured into a mixed solvent of 850 ml of heptane and 150 ml of isopropyl alcohol to precipitate a resin and filtered. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 11.75 g of a white solid (yield 63.2%).
The chemical formula of the obtained resin is as the following chemical formula (8). Its mass average molecular weight (Mw) was 9700, and dispersity (Mw / Mn) was 1.76. This is designated as resin 12.
When confirmed by carbon NMR, the composition ratio (mol%) was m / n = 20/80.

  The compositions (mol%), mass average molecular weights, and dispersities of the resins obtained in Synthesis Examples 1 to 12 are collectively shown in Table 1.

[Production of resist composition]
The negative resist composition of each Example and the comparative example was manufactured by mixing the material of Table 2. The amount of solvent used was adjusted so that the resist solid concentration was about 8% by mass.

[Evaluation]
The resist compositions of Examples and Comparative Examples were evaluated as follows.
An organic antireflection coating composition “AR-19” (trade name, manufactured by Shipley) is applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 215 ° C. for 60 seconds to dry. Thus, an organic antireflection film having a film thickness shown in Table 3 was formed.
Then, the negative resist composition is applied onto the antireflection film using a spinner, pre-baked (PAB) on the hot plate under the conditions shown in Table 3, and dried to obtain resists having the thicknesses shown in Table 3. A layer was formed.
Next, an ArF excimer laser (193 nm) is selectively passed through a mask pattern (binary) using an ArF exposure apparatus NSR-S302 (manufactured by Nikon Corporation; NA (numerical aperture) = 0.60, 2/3 ring zone). Irradiated.
Then, PEB treatment was performed under the conditions shown in Table 3, followed by paddle development with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, followed by washing with water for 20 seconds and drying to form a resist pattern.

At this time, the exposure amount (sensitivity) formed with a line and space width of 1: 1 in a 140 nm line and space pattern (shown as L & S or LS) was determined. For the comparative example, the exposure amount (sensitivity) formed with a line and space width of 1: 1 in a 160 nm line and space pattern (L & S) was determined.
Then, the resolution of the L & S pattern was changed to obtain a limit resolution (resolution evaluation) that can be resolved with this exposure amount.
Furthermore, the cross-sectional shape of the pattern was observed with a scanning electron microscope, and the swelling was evaluated.
The results are shown in Table 4.

From the results shown in Table 4, it was confirmed that in the examples according to the present invention, swelling can be suppressed and a fine resist pattern can be formed.

Synthesis example 13
NBHFAA 13.3 g, RHMA-M 3.13 g, and AdOHA 6.0 g, and 0.7 g of azobisisoacetate dimethyl 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 the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 14.9 g of a white solid (yield 66.5%).
The chemical formula of the obtained resin is the following chemical formula (9). Its mass average molecular weight (Mw) was 6300, and dispersity (Mw / Mn) was 1.83. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 42/29/29. This is designated as resin 13.

Synthesis example 14
13.3 g of NBHFAA, 3.51 g of HEMA, and 6.0 g of AdOHA, and 0.7 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 150 ml of THF and poured into 1000 ml of heptane to precipitate the resin, followed by filtration. Next, the precipitated resin was taken out, dissolved in 150 ml of THF, and then poured into 2000 ml of heptane to precipitate the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 19.8 g of a white solid (yield 86.8%).
The obtained resin is represented by the chemical formula (4). The mass mean molecular weight (Mw) was 7500, and dispersion degree (Mw / Mn) was 2.15.
When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 42/42/29. This is referred to as Resin 14.

Synthesis example 15
13.3 g of NBHFAA, 2.54 g of HEMA, and 4.34 g of AdOHA and 0.7 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 150 ml of THF and poured into 1000 ml of heptane to precipitate the resin, followed by filtration. Next, the precipitated resin was taken out, dissolved in 150 ml of THF, and then poured into 2000 ml of heptane to precipitate the resin, followed by filtration. The obtained resin was dried in a dryer at 40 ° C. for 24 hours to obtain 14.9 g of a white solid (yield 73.8%).
The obtained resin is represented by the chemical formula (4). Its mass average molecular weight (Mw) was 6500, and dispersity (Mw / Mn) was 1.92.
When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 50/25/25. This is designated as resin 15.

Synthesis Example 16
9.19 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 100 ml of THF, and poured into 2000 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 11.4 g of a white solid (yield 75.0%).
The chemical formula of the obtained resin is the chemical formula (5). The mass mean molecular weight (Mw) was 3100, and dispersion degree (Mw / Mn) was 1.68. When confirmed by carbon NMR, the composition ratio (mol%) was 1 / n = 60/40. This is designated as resin 16.

Synthesis Example 17
NBHFAA 12.25 g, HEMA 2.34 g, AdOHA 6.0 g, and GBLA 1.40 g and 0.7 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 200 ml of THF, and poured into 2000 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 10.9 g of a white solid (yield 49.6%).
The obtained resin is represented by the following chemical formula (10). Its mass average molecular weight (Mw) was 6000, and dispersity (Mw / Mn) was 2.23.
When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n / o = 40/20/30/10. This is designated as resin 17.

Synthesis Example 18
NBHFAA 12.25 g, HEMA 2.34 g, AdOHA 6.0 g, and NBLA 2.0 g and 0.7 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 200 ml of THF, and poured into 2000 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 13.9 g of a white solid (yield 61.5%).
The obtained resin is represented by the following chemical formula (11). Its mass average molecular weight (Mw) was 5600, and dispersity (Mw / Mn) was 2.24.
When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n / o = 40/20/30/10. This is designated as resin 18.

Synthesis Example 19
9.19 g of NBHFAA, 6.0 g of AdOHA, and 1.33 g of NBLA and 0.7 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 200 ml of THF, and poured into 2000 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 13.3 g of a white solid (yield 80.5%).
The obtained resin is represented by the following chemical formula (12). Its mass average molecular weight (Mw) was 3100, and dispersity (Mw / Mn) was 1.77.
When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 45/45/10. This is designated as resin 19.

Synthesis example 20
9.19 g of NBHFAA, 6.0 g of AdOHA, and 0.93 g of GBLA and 0.7 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 200 ml of THF, and poured into 2000 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 12.4 g of a white solid (yield 76.9%).
The obtained resin is represented by the following chemical formula (13). Its mass average molecular weight (Mw) was 3000, and dispersity (Mw / Mn) was 1.83.
When confirmed by carbon NMR, the composition ratio (mol%) was 1 / m / n = 45/45/10. This is designated as resin 20.

  Table 5 shows the compositions (mol%), mass average molecular weights (Mw), and dispersities (Mw / Mn) of the resins obtained in Synthesis Examples 13 to 20.

[Production of resist composition]
The negative resist composition of each Example and the comparative example was manufactured by mixing the material of Table 6.

[Evaluation]
The resolution, pattern shape, and sensitivity were evaluated in the same manner as in the above example except that the conditions at the time of resist pattern formation were changed to the conditions shown in Table 7 below. The results are shown in Table 8.

  From the results shown in Table 8, it was confirmed that in the examples according to the present invention, swelling can be suppressed and a fine resist pattern can be formed.

Claims (26)

  A structural unit (a1) containing an alicyclic group having a fluorinated hydroxyalkyl group, a structural unit derived from an acrylate ester, and a structural unit (a2) containing a hydroxyl group-containing alicyclic group; Resin for resist composition characterized by having. Resin for resist compositions of Claim 1 WHEREIN: Resin for resist compositions whose structural unit (a1) is represented by following General formula (1).

(In the formula, R is 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).  Resin for resist compositions of Claim 1 or 2 WHEREIN: Resin for resist compositions whose carbon number of the alicyclic group of a structural unit (a2) is 5-15. Resin for resist compositions as described in any one of Claims 1-3 WHEREIN: Resin for resist compositions whose structural unit (a2) is represented by following General formula (2).

(R is a hydrogen atom, an alkyl group, a fluorinated alkyl group or a fluorine atom, and q is an integer of 1 to 3.)   The resin for resist compositions according to any one of claims 1 to 4, wherein the proportion of the structural unit (a1) is 20 to 80 mol% and the proportion of the structural unit (a2) is 20 to 80 mol%. Resin for composition.   The resin for a resist composition according to any one of claims 1 to 5, further comprising a structural unit derived from acrylic acid and having no cyclic structure, the side chain having an alcoholic hydroxyl group. Resin for resist composition which has a unit (a3). Resin for resist compositions of Claim 6 WHEREIN: Resin for resist compositions whose structural unit (a3) is represented by following General formula (3).

Wherein R ¹ is a hydrogen atom, an alkyl group, a fluorinated alkyl group, a fluorine atom or a hydroxyalkyl group, R ² is a hydrogen atom, an alkyl group or a hydroxyalkyl group, and R ¹ , R ² At least one of them is a hydroxyalkyl group.)   Resin for resist compositions of Claim 6 or 7 WHEREIN: Resin for resist compositions in which a structural unit (a3) contains the structural unit induced | guided | derived from alpha- (hydroxyalkyl) acrylic acid alkylester.   Resin for resist compositions as described in any one of Claims 6-8 WHEREIN: Resin for resist compositions in which a structural unit (a3) contains the structural unit induced | guided | derived from the ((alpha) -alkyl) acrylic acid hydroxyalkyl ester. .   The resin for a resist composition according to any one of claims 6 to 9, wherein the proportion of the structural unit (a1) is 20 to 80 mol%, the proportion of the structural unit (a2) is 10 to 70 mol%, and the structural unit. Resin for resist composition whose ratio of (a3) is 10-70 mol%.   Resin for resist compositions as described in any one of Claims 1-5 WHEREIN: Resin for resist compositions which has the structural unit (a4) induced | guided | derived from the acrylate ester containing a lactone containing monocyclic or polycyclic group .   Resin for resist compositions of Claim 11 WHEREIN: Resin for resist compositions in which a structural unit (a4) contains the structural unit induced | guided | derived from the acrylate ester containing norbornane lactone.   The resin for a resist composition according to claim 11 or 12, wherein the proportion of the structural unit (a1) is 20 to 80 mol%, the proportion of the structural unit (a2) is 10 to 70 mol%, and the proportion of the structural unit (a4). Resin for resist composition whose is 10-70 mol%.   Resin for resist compositions as described in any one of Claims 6-10 WHEREIN: Resin for resist compositions which has the structural unit (a4) induced | guided | derived from the acrylate ester containing a lactone containing monocyclic or polycyclic group .   Resin for resist compositions of Claim 14 WHEREIN: Resin for resist compositions in which the said structural unit (a4) contains the structural unit induced | guided | derived from the acrylate ester containing norbornane lactone.   The resin for a resist composition according to claim 14 or 15, wherein the proportion of the structural unit (a1) is 10 to 85 mol%, the proportion of the structural unit (a2) is 10 to 80 mol%, and the proportion of the structural unit (a3). Is a resin for a resist composition in which the proportion of the structural unit (a4) is 1 to 70 mol%.   The resin for resist compositions according to any one of claims 11 to 16, wherein the structural unit (a4) is a structural unit in which a hydrogen atom is bonded to the α-position.     Resin for resist compositions of any one of Claims 2-17 WHEREIN: Resin for resist compositions whose R in General formula (1) is a hydrogen atom. In the resin for resist compositions according to any one of claims 1 to 18,
The structural unit (a2) is a resin for a resist composition, which is a structural unit in which a hydrogen atom is bonded to the α-position.    Resin for resist compositions as described in any one of Claims 1-19 WHEREIN: Resin for resist compositions whose mass mean molecular weight is the range of 2000-30000.   A negative containing the resin for a resist composition according to any one of claims 1 to 20, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component. Type resist composition.   The negative resist composition according to claim 21, wherein the component (B) is an onium salt having a fluorinated alkyl sulfonate ion as an anion.   The negative resist composition according to claim 21 or 22, wherein the component (C) is at least one selected from melamine-based crosslinking agents, urea-based crosslinking agents, ethyleneurea-based crosslinking agents, and glycoluril-based crosslinking agents. A negative resist composition.   The negative resist composition according to any one of claims 21 to 23, further comprising a nitrogen-containing organic compound.   The negative resist composition according to any one of claims 21 to 24, wherein the negative resist composition is for a process using an ArF excimer laser as an exposure light source. A negative resist composition according to any one of claims 21 to 25 is applied on a substrate, pre-baked, selectively exposed, subjected to PEB (post-exposure heating), and alkali-developed. And forming a resist pattern.