JP4563227B2 - Negative resist composition and resist pattern forming method - Google Patents

Description

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

In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, miniaturization has been progressing rapidly due to advances in lithography technology.
As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line were used, but now KrF excimer laser (248 nm) is the center of mass production, and ArF excimer laser (193 nm) is mass-produced. It has begun to be introduced. Research is also being conducted on lithography technology using an F ₂ excimer laser (157 nm), EUV (extreme ultraviolet light), EB (electron beam) or the like as a light source (radiation source).

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

Further, a negative resist composition that can be applied to a process using an ArF excimer laser with a shorter wavelength has been proposed (see, for example, Patent Document 2).
For example, a negative resist composition is proposed that uses, as a base resin, a homopolymer having a main chain of norbornane, which is a cyclic olefin polymer (poly (cyclic) olefin: PCO), and a hydroxyfluorinated alkyl group in the side chain. (See Patent Document 2 [00202]).
Japanese Patent Publication No. 8-3635 International Publication No. 2004/076495 Pamphlet

  However, in a negative resist composition using conventional PCO, the alkali solubility in the unexposed area is not sufficient, and it is difficult to control the contrast.

In the present specification, “alkali solubility” refers to a property that an unexposed portion is dissolved by a developer when alkali development is performed after selective exposure.
If the “alkali solubility” in the unexposed area is poor, there will be inconveniences such as undissolved area remaining unsolved and reduced resolution.

Further, in this specification, “contrast” for a negative resist composition and its resist pattern means that when exposed to alkali after selective exposure, the exposed portion is insoluble in an alkali developer by crosslinking. The characteristic which becomes.
If the “contrast” is poor, the exposed area is dissolved after development. For this reason, for example, a problem such as a decrease in resolution occurs.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a negative resist composition and a resist pattern forming method capable of improving alkali solubility and obtaining good contrast.

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by using a copolymer containing a specific structural unit in a specific ratio as a resin component of a negative resist composition. The present invention has been completed.
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). The alkali-soluble resin component (A) is represented by the following general formula (a1-1)

[Wherein, X is a fluorinated hydroxyalkyl group, and r is 0 or 1. And a structural unit (a1) represented by the following general formula (a2-1)

[Wherein, R ¹ and R ² are each independently a hydrogen atom or a lower alkyl group, R ′ is a hydrogen atom or a hydroxyalkyl group, r is 0 or 1, and p is an integer of 1 to 3. It is. Structural units represented by] (a2) and become from, and in the total number of moles of the structural unit (a1) and the structural unit (a2), the structural unit of (a1) 60 to 8 0 mol%, the structural unit (a2) Is a negative resist composition comprising a copolymer (A1) containing 20 to 40 mol%.
In the second aspect of the present invention, the negative resist composition of the first aspect is applied on a substrate, pre-baked, selectively exposed, then subjected to PEB (post-exposure heating), and alkali The resist pattern forming method is characterized in that a resist pattern is formed by development.

In the following description, the meanings of terms are as follows.
“Structural unit” refers to a monomer unit constituting a polymer (resin).
The “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
“Exposure” is a concept that encompasses not only light irradiation but also radiation irradiation such as electron beam irradiation.

  According to the present invention, there are provided a negative resist composition and a resist pattern forming method capable of improving the alkali solubility in an unexposed portion and obtaining a good contrast.

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

  In this invention, a component (A) contains the structural unit (a1) represented by the said general formula (a1-1), and the structural unit (a2) represented by the said general formula (a2-1), And the copolymer (A1) containing 60 to 89 mol% of the structural unit (a1) and 11 to 40 mol% of the structural unit (a2) in the total number of moles of the structural unit (a1) and the structural unit (a2). .

・ Structural unit (a1)
The structural unit (a1) is a structural unit represented by the general formula (a1-1) and having a norbornane or tetracyclododecane structure having a fluorinated hydroxyalkyl group in the main chain.
In the present invention, when the component (A) contains the copolymer (A1) having the structural unit (a1) having such a structure, the effect of improving the solubility in an alkali developer is improved. In addition, since the main chain has a norbornane or tetracyclododecane structure having a high carbon density, etching resistance is also improved.

  In formula (a1-1), r is 0 or 1, and is preferably 0 because it is easily available industrially.

In the formula (a1-1), the “fluorinated hydroxyalkyl group” represented by X is a hydroxyalkyl group in which part of the hydrogen atoms of the alkyl group is substituted with a hydroxy group. Some or all of the remaining hydrogen atoms are substituted with fluorine.
In the fluorinated hydroxyalkyl group, the hydrogen atom of the hydroxy group is easily released by fluorination.
In the fluorinated hydroxyalkyl group, the alkyl group is preferably a linear or branched alkyl group.
Although carbon number of this alkyl group is not specifically limited, 1-20 are preferable, 4-16 are more preferable, and it is most preferable that it is 4-12.
The number of hydroxy groups is not particularly limited, but is preferably one.
Among them, as the fluorinated hydroxyalkyl group, a fluorinated alkyl group and / or a fluorine atom is bonded to the carbon atom to which the hydroxy group is bonded (here, the α-position carbon atom of the hydroxyalkyl group). Is preferred.
Here, 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.
Further, the alkyl group of the fluorinated alkyl group is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and more preferably 1 carbon atom.

  Among them, X is particularly preferably a group represented by the following general formula (a1-1-1) because the effects of the present invention are improved. Further, the resist pattern shape is excellent, and line edge roughness (LER) is reduced, which is preferable. Here, the line edge roughness (LER) refers to uneven unevenness of the line side wall.

［式中、Ｒ^１１，Ｒ^１２はそれぞれ独立して水素原子または低級アルキル基であり、ｍ，ｎはそれぞれ独立して１〜５の整数であり、ｑは１〜５の整数である。］

[Wherein, R ¹¹ and R ¹² are each independently a hydrogen atom or a lower alkyl group, m and n are each independently an integer of 1 to 5, and q is an integer of 1 to 5. ]

In formula (a1-1-1), R ¹¹ and R ¹² are each independently a hydrogen atom or a lower alkyl group.
The lower alkyl group is preferably a linear or branched lower alkyl group having 5 or less carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, A pentyl group, an isopentyl group, a neopentyl group, etc. are mentioned, and a methyl group is preferable.
Among these, it is preferable that R ¹¹ and R ¹² are both hydrogen atoms.
q is an integer of 1 to 5, more preferably an integer of 1 to 3, and most preferably 1.
m and n are each independently an integer of 1 to 5, more preferably an integer of 1 to 3. In particular, those in which m and n are 1 are preferable because they are excellent in synthesis and effect.

As the structural unit (a1), one type or a mixture of two or more types can be used.
In the copolymer (A1), the proportion of the structural unit (a1) is preferably 60 to 89 mol%, more preferably 65 to 85 mol%, based on the total of the structural unit (a1) and the structural unit (a2). 65 to 80 mol% is more preferable. Alkali solubility improves by being more than the lower limit of the said range. Further, an effect of improving etching resistance can be obtained. On the other hand, the balance with other structural units becomes favorable by being below an upper limit.

・ Structural unit (a2)
The structural unit (a2) is a structural unit represented by the general formula (a2-1) and having a norbornane or tetracyclododecane structure having a hydroxyl group-containing alkyl group in the main chain.
In the present invention, the effect of obtaining a good contrast is improved by containing the copolymer (A1) having the structural unit (a2) having such a structure. In addition, since the main chain has a norbornane or tetracyclododecane structure having a high carbon density, etching resistance is also improved.

In formula (a2-1), R ¹ and R ² each independently represent a hydrogen atom or a lower alkyl group. The lower alkyl group is represented by R ¹¹ or R ¹² in formula (a1-1-1). The same thing as the lower alkyl group made is mentioned. Among these, it is preferable that R ¹ and R ² are both hydrogen atoms.
R ′ is a hydrogen atom or a hydroxyalkyl group, and the hydroxyalkyl group is preferably a linear or branched hydroxyalkyl group having 10 or less carbon atoms, more preferably a straight chain having 2 to 8 carbon atoms. It is a chain or branched hydroxyalkyl group, more preferably a linear lower hydroxyalkyl group having 1 to 3 carbon atoms.
The number of hydroxyl groups and the bonding position in the hydroxyalkyl group are not particularly limited, but are usually one and preferably bonded to the terminal of the alkyl group.
Of these, R ′ is particularly preferably a hydrogen atom.
r is 0 or 1, and 0 is preferable.
p is an integer of 1 to 3, preferably 1 or 2, and most preferably 1.

  Specific examples of the structural unit (a2) include the following chemical formulas (a2-1-1) to (a2-1-7).

Among these, the above formulas (a2-1-1), (a2-1-2), and (a2-1-3) are preferable because the effects of the present invention are high.
As the structural unit (a2), one type or a mixture of two or more types can be used.
In the copolymer (A1), the proportion of the structural unit (a2) is preferably 11 to 40 mol%, more preferably 15 to 35 mol% with respect to the total of the structural unit (a1) and the structural unit (a2). 15-30 mol% is more preferable. Contrast improves by being more than the lower limit of the said range. Further, an effect of improving etching resistance can be obtained. By being below the upper limit, the balance with other structural units becomes good.

The copolymer (A1) may have other copolymerizable structural units other than the structural units (a1) and (a2).
As the structural units other than the structural units (a1) and (a2), for example, structural units that are used in the known component (A) for conventional chemically amplified resist compositions can be appropriately used. For example, 5-norbornanecarboxylic acid hydroxyethyl ester, 5-norbornanecarboxylic acid trimethylsilane ester, 5-norbornane-2-methanol acetate, 5-triethoxysilylnorbornane, 5-norbornanecarboxylic acid 1-methylcyclopentyl ester, 5-norbornane Examples thereof include carboxylic acid tetrahydro-2-oxo-3-furanyl ester, a mixture thereof, a structural unit derived from norbornane, a structural unit derived from tetrafluoroethylene, and a structural unit derived from maleic anhydride.

However, for the effect of the present invention, the copolymer (A1) is preferably a resin mainly composed of the structural units (a1) and (a2).
Here, the “main component” means that the total of the structural unit (a1) and the structural unit (a2) occupies 70 mol% or more, and preferably 80 mol% or more. Among these, a copolymer composed of the structural units (a1) and (a2) is preferable.
In addition, as a preferable combination of the structural unit (a1) and the structural unit (a2) in the copolymer (A1), the following chemical formulas (A1-1) to (A1-4) may be mentioned as examples.

-Mass average molecular weight The mass average molecular weight (Mw; polystyrene-converted mass average molecular weight by gel permeation chromatography) of the copolymer (A1) is preferably 2000 to 10,000, more preferably 3000 to 6000, and particularly preferably 3000 to 5000. A favorable contrast can be obtained by being more than the lower limit of the said range, and swelling of a resist pattern can be suppressed by being below an upper limit. As a result, the resolution is improved. Further, since the swelling of the pattern can be suppressed, the effect of improving the depth of focus (DOF) characteristic and the effect of suppressing the line edge roughness (LER) can be obtained.
Moreover, it is preferable to make the said mass mean molecular weight into this range from the point that the swelling inhibitory effect of a resist pattern is also high.
When the mass average molecular weight is within this range, the lower the tendency, the better characteristics can be obtained.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, and more preferably 1.0 to 2.5. Here, Mn represents a number average molecular weight.

  The copolymer (A1) can be synthesized by the method described in Patent Document 2 (International Publication No. 2004/076495 pamphlet).

The said copolymer (A1) can be used 1 type or in mixture of 2 or more types.
Moreover, as a ratio of the said copolymer (A1) in a component (A), 70 mass% or more is preferable, 80 mass% or more is more preferable, and 100 mass% is the most preferable.
Component (A) can be used by mixing resin components other than copolymer (A1), for example, alkali-soluble resins used in conventional negative resist compositions.
The content of the component (A) in the negative resist composition may be adjusted according to the resist film thickness to be formed.

The component (B) is not particularly limited, and those that have been proposed so far as acid generators for chemically amplified resists can be used.
Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, poly (bissulfonyl) diazomethanes, and the like. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

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

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基またはアルキル基を表し；Ｒ^４”は、直鎖、分岐または環状のアルキル基またはフッ素化アルキル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; R ⁴ ″ represents a linear, branched or cyclic alkyl group or fluorinated group. Represents an alkyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. At least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all R ¹ ″ to R ³ ″ are aryl groups.
The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may be substituted with a group, a halogen atom or the like, or may not be substituted.
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, it is most preferable that all of R ¹ ″ to R ³ ″ are phenyl groups.

R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group.
The linear alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group is a cyclic group as indicated by R ¹ ″ and preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and more preferably 6 carbon atoms. Most preferably, it is -10.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
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. Of R ⁵ ″ to R ⁶ ″, two or more are preferably aryl groups, and most preferably R ⁵ ″ to R ⁶ ″ are all aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"The, ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

  Specific examples of the onium salt-based acid generator include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, and triphenylsulfonium trifluoromethane. Sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethane Sulfonate, its heptafluoropropane sulphonate or its Nafluorobutane sulfonate, trifluoromethane sulfonate of monophenyldimethylsulfonium, heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof, trifluoromethane sulfonate of diphenyl monomethylsulfonium, heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof, (4- Trifluoromethanesulfonate of methylphenyl) diphenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of (4-methoxyphenyl) diphenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, tri (4 -Tert-bu E) phenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, diphenyl (1- (4-methoxy) naphthyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate Is mentioned. In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

  Moreover, what replaced the anion part by the anion part represented by the following general formula (b-3) or (b-4) in the said general formula (b-1) or (b-2) can also be used. (The cation moiety is the same as (b-1) or (b-2)).

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

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms and substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Preferably it is C3.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably It is C1-C7, More preferably, it is C1-C3.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less This is preferable because the transparency to the surface is improved.
The proportion of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all hydrogen atoms are substituted with fluorine atoms. A perfluoroalkylene group or a perfluoroalkyl group.

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

［式（Ｂ−１）中、Ｒ^２１、Ｒ^２２はそれぞれ独立に有機基を表す。］

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

In the present invention, an organic group is a group containing a carbon atom, and has an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom (a fluorine atom, a chlorine atom, etc.)). You may do it.
The organic group for R ²¹ is preferably a linear, branched or cyclic alkyl group or aryl group. These alkyl groups and aryl groups may have a substituent.
There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned.
Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable.
The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
As the aryl group, a partially or completely halogenated aryl group is particularly preferable.
The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ²¹ is particularly preferably a C 1-4 alkyl group having no substituent or a C 1-4 fluorinated alkyl group.

As the organic group for R ²² , a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable.
As the alkyl group and aryl group for R ^22, the same alkyl groups and aryl groups as those described above for R ²¹ can be used.
R ²² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

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

［式（Ｂ−２）中、Ｒ^３１は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３２はアリール基である。Ｒ^３３は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³¹ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³² is an aryl group. R ³³ is an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３４はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３５は２または３価の芳香族炭化水素基である。Ｒ^３６は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐは２または３である。］

[In the formula (B-3), R ³⁴ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁵ is a divalent or trivalent aromatic hydrocarbon group. R ³⁶ is an alkyl group having no substituent or a halogenated alkyl group. p is 2 or 3. ]

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

As the aryl group of R ³² , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthracyl group, a phenanthryl group, or the like. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group represented by R ³² may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.

The alkyl group or halogenated alkyl group having no substituent for R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group, and most preferably a partially fluorinated alkyl group.
The fluorinated alkyl group in R ³³ preferably has 50% or more of the hydrogen atom of the alkyl group, more preferably 70% or more, and even more preferably 90% or more. This is preferable because the strength of the acid is increased. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁴ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^31. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁵ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³² .
Examples of the alkyl group or halogenated alkyl group having no substituent for R ³⁶ include the same alkyl groups or halogenated alkyl groups as those having no substituent for R ³³ .
p is preferably 2.

Specific examples of 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.
Moreover, the compound represented by the following chemical formula is mentioned.

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

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

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane (when A = 3) and 1,4-bis (phenylsulfonyldiazo) having the following structure. Methylsulfonyl) butane (when A = 4), 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane (when A = 6), 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane (A = 10) 1), 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane (when B = 2), 1,3-bis (cyclohexylsulfonyldiazomethylsulfonyl) propane (when B = 3), 1,6- Bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane (when B = 6) (For B = 10) 1,10-bis (cyclohexyl diazomethylsulfonyl) decane and the like.

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

As a component (B), these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
Content of the component (B) in the negative resist composition of this invention is 0.5-30 mass parts with respect to 100 mass parts of components (A), 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.

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

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

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

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

  Examples of the alkylene urea-based crosslinking agent include compounds represented by the following general formula (III).

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

[Wherein, R ^{1 ′} and R ^{2 ′} each independently represent a hydroxyl group or a lower alkoxy group, R ^{3 ′} and R ^{4 ′} each independently represent a hydrogen atom, a hydroxyl group or a lower alkoxy group, and v is 0 or 1 It is an integer of ~ 2. ]

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

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

  Specific examples of alkylene urea crosslinking agents 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 crosslinkers such as propylene urea, mono and / or dipropoxymethylated propylene urea, mono and / or dibutoxymethylated propylene urea; 1,3-di (methoxymethyl) 4,5-dihydroxy- - imidazolidinone, 1,3-mentioned and (methoxymethyl) -4,5-dimethoxy-2-imidazolidinone.

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

As a component (C), 1 type may be used independently and 2 or more types may be used in combination.
3-30 mass parts is preferable with respect to 100 mass parts of components (A), as for the compounding quantity of a component (C), 3-15 mass parts is more preferable, and 5-10 mass parts is the most preferable. When the content of the component (C) is at least the lower limit value, the crosslinking formation proceeds sufficiently and a good resist pattern can be obtained. Moreover, when it is below this upper limit, the storage stability of the resist coating solution is good, and the deterioration of sensitivity with time is suppressed.

In the negative resist composition of the present invention, a nitrogen-containing organic compound (D) (hereinafter referred to as component (D)) is further added as an optional component in order to improve the resist pattern shape, stability over time and the like. Can be blended.
Since a wide variety of components (D) have already been proposed, any known one may be used, but aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred. .
Examples of the aliphatic amine include amines (alkyl amines or alkyl alcohol amines) in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms. Specific examples thereof include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di-n-heptylamine, Dialkylamines such as di-n-octylamine and dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-heptyl Trialkylamines such as amine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n -Ok Noruamin, alkyl alcohol amines such as tri -n- octanol amine. Among these, alkyl alcohol amines and trialkyl amines are preferable, and alkyl alcohol amines are most preferable. Of the alkyl alcohol amines, triethanolamine and triisopropanolamine are most preferred.
These may be used alone or in combination of two or more.
Component (D) is usually used in an amount of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of component (A).

In the negative resist composition of the present invention, an organic carboxylic acid is further added as an optional component for the purpose of preventing sensitivity deterioration due to the blending of the component (D) and improving the resist pattern shape, stability over time, etc. Alternatively, phosphorus oxo acid or a derivative thereof (E) (hereinafter referred to as component (E)) can be contained. In addition, a component (D) and a component (E) 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.
Component (E) is used in a proportion of 0.01 to 5.0 parts by mass per 100 parts by mass of component (A).

The negative resist composition of the present invention can be produced by dissolving the material in an organic solvent.
As the organic solvent (S), any solvent can be used as long as it can dissolve each component to be used to form a uniform solution. Any one of conventionally known solvents for chemical amplification resists can be used. Or it can select and use 2 or more types suitably.
For example, lactones such as γ-butyrolactone, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl 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, can be mentioned esters such as ethyl ethoxypropionate. Among these, propylene glycol monomethyl ether (PGME) is preferable. A mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) is more preferable. The mixing ratio of PGMEA and PGME is preferably 9: 1 to 1: 9 by mass ratio, more preferably 8: 2 to 2: 8, and most preferably 8: 2 to 5: 5. By setting it as the said range, the effect of this invention will become further excellent.
These organic solvents (S) may be used alone or as a mixed solvent of two or more.
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, but is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to do.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2.
In addition, as the organic solvent (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 organic solvent (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 It is used so that it may become 2-20 mass%, Preferably it is 5-15 mass%.

  In the negative resist composition of the present invention, if desired, there are further miscible additives such as an additional resin for improving the performance of the resist film, a surfactant for improving the coating property, a dissolution inhibitor, 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 improve the alkali solubility and form a resist pattern with good contrast.
This is because the copolymer (A1) contains 60 to 89 mol% of the structural unit (a1), thereby having many hydroxyl groups with high alkali solubility. Thereby, it is estimated that the alkali solubility required for a resist improves.
On the other hand, when the copolymer (A1) contains 11 to 40 mol% of the structural unit (a2), it is presumed that good contrast can be obtained by improving the crosslinkability. As a result, excellent effects such as improved resolution can be obtained by an appropriate balance between alkali solubility and contrast. In addition, since the resolution is improved, the exposure margin is also improved.
Furthermore, since the structural unit (a1) and the structural unit (a2) have a norbornane or tetracyclodecanyl structure with high carbon density, etching resistance is improved. In addition, the negative resist composition of the present invention has good sensitivity and improves temporal stability.

[Resist pattern formation method]
In the resist pattern forming method, the negative resist composition of the present invention is applied on a substrate, pre-baked, selectively exposed, then subjected to PEB (post-exposure heating), and alkali-developed to form a resist pattern. It is characterized by forming.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the negative resist composition is applied onto a substrate such as a silicon wafer with a spinner or the like. Then, prebaking is performed for 40 to 120 seconds, preferably 60 to 90 seconds, under a temperature condition of 80 to 150 ° C. For example, after selectively exposing ArF excimer laser light through a desired mask pattern with an ArF exposure apparatus or the like, PEB (post-exposure heating) is performed for 40 to 120 seconds under a temperature condition of 80 to 150 ° C. Preferably, it is applied for 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.

Examples of the inorganic antireflection film include a silicon substrate provided with a thin film such as SiO ₂ , SiON, SiN, Si ₃ N ₄ , polycrystalline silicon, or TiN.

The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation.
In particular, the negative resist composition of the present invention is effective for an ArF excimer laser.

  According to the present invention, a negative resist composition and a resist pattern forming method capable of improving alkali solubility and obtaining good contrast are provided.

In the following Examples 1-3 and Comparative Examples 1-4, the following component (A), (B), (C), (D) and the organic solvent (S) were used.
Component (A): A resin represented by the following chemical formula (A1-1) was used. The resins are (A) -1 to (A) -7 shown in Table 1, and the proportion of the structural units (mol%), mass average molecular weight (Mw), and dispersity (Mw / Mn) (Mn: number average molecular weight). )showed that.

(Examples 1-3, Comparative Examples 1-4)
With the composition shown in Table 2, a negative resist composition was prepared. In addition, the numerical value in [] shows a compounding quantity (mass part).

(B) -1: Triphenylsulfonium trifluoromethanesulfonate (C) -1: Tetramethoxymethylated glycoluril (trade name: MX270 (manufactured by Sanwa Chemical Co., Ltd.))
(D) -1: Triisopropanolamine S1: PGME
S2: PGMEA: PGME = 6: 4 mixed solvent

The following evaluation was performed using the obtained negative resist composition.
An organic antireflection film composition “ARC-29” (trade name, manufactured by Shipley Co., Ltd.) is applied onto a substrate (8-inch silicon wafer) on an 8-inch silicon wafer using a hot plate. By baking and drying at 215 ° C. for 90 seconds, an organic antireflection film having a film thickness of 77 nm was formed.
The negative resist composition obtained above is uniformly applied on the organic antireflection film using a spinner, and prebaked (PAB) on a hot plate at 80 ° C./60 seconds for drying. Thus, a resist layer having a thickness of 200 nm was formed.
Next, an ArF excimer laser (193 nm) was selectively irradiated through the mask pattern by an ArF exposure apparatus NSR-S302 (manufactured by Nikon; NA (numerical aperture) = 0.60, 2/3 annular illumination). .
Then, PEB treatment was performed at 100 ° C./60 seconds, followed by paddle development with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, and then water rinsing with pure water for 30 seconds. Shaking and drying were performed to form a 1: 1 130 nm line and space pattern (LS).

As for sensitivity, the optimum exposure dose (Eop, mJ / cm ² ) when forming a 1: 1 130 nm LS pattern was measured.
Regarding the resolution, the limit resolution that can be resolved at the optimum exposure amount (Eop) was measured.
These evaluation results are shown in Table 3. In addition,-and * 1- * 3 in a table | surface are as follows.
-: A resist pattern is not formed and measurement is impossible.
* 1: The unexposed part did not dissolve in the developer (poor alkali solubility).
* 2: The unexposed part was left undissolved (poor alkali solubility).
* 3: The resist film was completely dissolved during development (contrast was poor).

As shown in Table 3, the negatives of Examples 1 to 3 using the resins of (A) -3, (A) -6, and (A) -7, which are alkali-soluble resin components (A) according to the present invention. The mold resist composition has improved alkali solubility and good contrast. Thereby, the resolution was also excellent. The sensitivity was also good.
On the other hand, in Comparative Examples 1 and 2 using the resins (A) -1 to (A) -2 different from the component (A) in the present invention, the alkali solubility was poor and did not sufficiently dissolve in the developer. .
In Comparative Examples 3 to 4 using the resins (A) -4 to (A) -5, the contrast was poor and the resist film was completely dissolved during development.

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 represented by the following general formula (a1-1)

[Wherein, X is a fluorinated hydroxyalkyl group, and r is 0 or 1. ]
A structural unit (a1) represented by the following general formula (a2-1)

[Wherein, R ¹ and R ² are each independently a hydrogen atom or a lower alkyl group, R ′ is a hydrogen atom or a hydroxyalkyl group, r is 0 or 1, and p is an integer of 1 to 3. It is. ]
In it because structural units (a2) represented, and in the total number of moles of the structural unit (a1) and the structural unit (a2), the structural unit of (a1) sixty to eight 0 mol%, the structural unit (a2) A negative resist composition comprising a copolymer (A1) containing 20 to 40 mol%.   The negative resist composition according to claim 1, wherein the copolymer (A1) has a mass average molecular weight of 2000 to 10,000. X is the following general formula (a1-1-1)

[Wherein, R ¹¹ and R ¹² are each independently a hydrogen atom or a lower alkyl group, m and n are each independently an integer of 1 to 5, and q is an integer of 1 to 5. The negative resist composition according to claim 1, wherein the negative resist composition is a group represented by the formula:   The said crosslinking agent component (C) is at least 1 sort (s) chosen from the group which consists of a melamine type crosslinking agent, a urea type crosslinking agent, an alkylene urea type crosslinking agent, and a glycoluril type crosslinking agent. Negative resist composition as described in the above item.   Furthermore, the negative resist composition as described in any one of Claims 1-4 containing a nitrogen-containing organic compound (D). The negative resist composition according to any one of claims 1 to 5 is applied on a substrate, pre-baked, selectively exposed, and then subjected to PEB (post-exposure heating) and alkali development. And forming a resist pattern.