JP2004334165A - Chemically amplified positive resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemically amplified positive resist composition which is suitable for excimer laser lithography with KrF, ArF, etc. is good in various resist performances such as sensitivity and resolution, and suppresses lowering of the smoothness of a pattern wall surface by a stationary wave effect caused particularly in application to a highly reflective substrate or by reduction in the thickness of a resist film. <P>SOLUTION: The chemically amplified positive resist composition contains a resin which itself is insoluble or hardly soluble in an aqueous alkali solution but is made soluble in the aqueous alkali solution by the action of an acid, an acid generator and a compound which has an aromatic ring, is ≤1,000 mol.wt. and has light absorption of molar extinction coefficient of ≥1,000 l/(mol*cm) in the wavelength region of 190-260 nm, wherein the compound contained is in an amount of 0.01-20 wt.% of the amount of the resin. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a chemically amplified positive resist composition used for fine processing of semiconductors.

  A lithography process using a resist composition is usually employed for microfabrication of a semiconductor. In lithography, an exposure wavelength is short in principle, as represented by a Rayleigh diffraction limit equation. The higher the resolution, the higher the resolution. Exposure light sources for lithography used in the manufacture of semiconductors have become shorter each year, such as g-line having a wavelength of 436 nm, i-line having a wavelength of 365 nm, and a KrF excimer laser having a wavelength of 248 nm. ArF excimer laser is promising.

Since the life of a lens used in an excimer laser exposure machine is shorter than that of a lens for a conventional exposure light source, it is desirable that exposure time to an excimer laser beam be as short as possible. For this purpose, since it is necessary to increase the sensitivity of the resist, a so-called chemically amplified resist containing a resin having a group that is cleaved by the acid by utilizing the catalytic action of an acid generated by exposure is used.
In recent years, the application of KrF and ArF resists to highly reflective substrates such as thinner resist films and ion implantation processes has been progressing, and the effect of the standing wave effect on resist performance, particularly on the variation in shape and line width. Is getting bigger.

However, in the conventionally known chemically amplified resist composition, a phenomenon that the resist side wall undulates or a phenomenon that line edge roughness, that is, a pattern side wall smoothness is reduced due to the effect of the standing wave occurs, and the line width uniformity is reduced. The problem of worsening occurs. In this regard, conventionally, there has been a technique using an antireflection film in order to suppress the influence of light reflected from the substrate (for example, see Patent Document 1).
Japanese Patent Publication No. 11-511194

  It is an object of the present invention to provide a chemically amplified positive resist composition suitable for excimer laser lithography such as KrF or ArF, which has various resist performances such as sensitivity and resolution, and is particularly suitable for highly reflective substrates. An object of the present invention is to provide a positive resist composition in which a reduction in the smoothness of the pattern wall surface due to the standing wave effect, which is caused by the application of the above-mentioned method or caused by a reduction in the resist film thickness, is improved.

  The present inventors have intensively studied a chemically amplified positive resist composition in order to improve the above-mentioned problems, and as a result, have a specific structure, a specific wavelength region, a light having a specific molar extinction coefficient. The present inventors have found that a chemically amplified positive resist composition containing a compound having absorption can solve the above problems, and have completed the present invention.

  That is, the present invention has a resin, an acid generator, and an aromatic ring which are insoluble or hardly soluble in an aqueous alkali solution, but are soluble in an aqueous alkali solution by the action of an acid, and have a molecular weight of 1,000 or less, A chemical compound having a light absorption coefficient of 1000 liter / (mol * cm) or more in a wavelength region of 190 nm to 260 nm, wherein the compound is in a range of 0.01 to 20% by weight based on the resin. The present invention relates to an amplification-type positive resist composition.

  The chemically amplified positive resist composition of the present invention is problematic when the resist film is thinned or applied to a highly reflective substrate. And a resist pattern with significantly improved dry etching resistance, sensitivity, and resolution. Therefore, this composition is suitable for exposure using an ArF or KrF excimer laser or the like, thereby giving a high-performance resist pattern.

（式中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６、Ｒ_７及びＲ_８は、互いに独立に水素原子、分岐していてもよいアルキル基、分岐していてもよいアルコキシ基、又は水酸基を表す。式中、Ｘ_１は、硫黄原子、酸素原子、又はＣＨ_２基を表す。）
で示される化合物及び下式（II）

（式中、Ｒ_９、Ｒ_１０、Ｒ_１１、Ｒ_１２、Ｒ_１３、Ｒ_１４、Ｒ_１５及びＲ_１６は、互いに独立に水素原子、分岐していてもよいアルキル基、分岐していてもよいアルコキシ基、カルボン酸エステル基、シアノ基、アミノ基、フェニル基、カルボキシル基、ベンゾイル基、水酸基、又はハロゲン原子を表す。ここで、アルキル基又はアルコキシ基の任意の炭素原子は、窒素原子で置換されていてもよい。式中の二重結合（ベンゼン環を除く）を含む構造は、シス型、トランス型のいずれの構造もとり得る。） The composition of the present invention contains a compound having an aromatic ring, a molecular weight of 1,000 or less, and having a light absorption of 5000 liter / (mol * cm) or more in a wavelength region of 190 nm to 260 nm. Is preferred.
Further, the composition of the present invention contains a compound having an aromatic ring, a molecular weight of 1,000 or less, and having a light absorption of not less than 1000 l / (mol * cm) in a wavelength region of 190 nm to 200 nm. Is preferred.
Further, the composition of the present invention contains a compound having an aromatic ring, a molecular weight of 1,000 or less, and having a light absorption of 1,000 liter / (mol * cm) or more in a wavelength region of 240 nm to 260 nm. Is preferred.
In the present invention, the compound has an aromatic ring, a molecular weight of 1,000 or less, a light absorption in a wavelength region of 190 nm to 260 nm, a molar absorption coefficient of 1000 liter / (mol * cm) or more, and At least one selected from the group consisting of the compounds represented by formula (I) is included.

(Wherein, R ₁ , R ₂ , R _3, R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each independently a hydrogen atom, an alkyl group which may be branched, or a branched atom. Represents an alkoxy group or a hydroxyl group, wherein X ₁ represents a sulfur atom, an oxygen atom, or a CH ₂ group.
And a compound represented by the following formula (II):

(In the formula, R ₉ , R ₁₀ , R _11, R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ and R ₁₆ are each independently a hydrogen atom, an optionally branched alkyl group, or an optionally branched group. Represents an alkoxy group, a carboxylate group, a cyano group, an amino group, a phenyl group, a carboxyl group, a benzoyl group, a hydroxyl group, or a halogen atom, wherein any carbon atom of the alkyl group or the alkoxy group is substituted with a nitrogen atom The structure containing a double bond (excluding a benzene ring) in the formula may be any of a cis-type structure and a trans-type structure.)

In the formula (I), the alkyl group for R _{1 to} R ₈ is preferably an alkyl group having 1 to 8 carbon atoms. As the alkyl group, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, sec-pentyl, neopentyl, tert-pentyl, 3-pentyl, hexyl, neohexyl, sec-hexyl , Heptyl, isoheptyl, neoheptyl, sec-heptyl, octyl, isooctyl, tert-octyl and the like.
The alkoxy group in R _{1 to} R ₈ is preferably an alkoxy group having 1 to 8 carbon atoms. As the alkoxy group, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentoxy, isopentoxy, sec-pentoxy, neopentoxy, tert-pentoxy, 3-pentoxy, hexyloxy, neohexyloxy, sec- Hexyloxy, peptyloxy, isoheptyloxy, neoheptyloxy, sec-heptyloxy, octyloxy, isooctyloxy, tert-octyloxy and the like.
In the formula (I), X ₁ is preferably a sulfur atom or an oxygen atom, and R _{1 to} R ₈ are preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms.
When two or more stereoisomers of the compound represented by the formula (I) exist due to cis / trans formation of a carbon-carbon double bond, any one or a mixture thereof is used in the present invention. .

In the formula (II), the alkyl group for R _{9 to} R ₁₆ is preferably an alkyl group having 1 to 8 carbon atoms, and at least one CH in the alkyl group may be substituted with a nitrogen atom. As the alkyl group, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, sec-pentyl, neopentyl, tert-pentyl, 3-pentyl, methylamino, dimethylamino, methyl Ethylamino, diethylamino, aminomethyl, aminoethyl and the like can be mentioned.
The alkoxy group in R _{9 to} R ₁₆ is preferably an alkoxy group having 1 to 8 carbon atoms, and at least one CH in the alkoxy group may be substituted by a nitrogen atom. As the alkoxy group, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentoxy, isopentoxy, sec-pentoxy, neopentoxy, tert-pentoxy, 3-pentoxy, aminomethoxy, N-methyl Aminomethoxy, N, N-dimethylaminomethoxy and the like can be mentioned.
The carboxylate (—COOR) in R _{9 to} R ₁₆ preferably has 2 to 9 carbon atoms. Examples of the carboxylate include alkoxycarbonyl, alkenyloxycarbonyl, and cycloalkyloxycarbonyl. Examples of the alkoxycarbonyl include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, pentoxycarbonyl, isopentoxy, sec-pentoxy, neopentoxy, tert-pent Toxylcarbonyl and the like. Examples of the alkenyloxycarbonyl include vinyloxycarbonyl, allyloxycarbonyl, 1-, 2- or 3-butenyloxycarbonyl, 1-, 2-, 3- or pentenyloxycarbonyl, and the like. Examples of the cycloalkyloxycarbonyl include cyclopentyloxycarbonyl, cyclopropoxycarbonyl, cyclobutyroxycarbonyl, cyclohexyloxycarbonyl, cycloheptyloxycarbonyl and the like.

The compounds can also be used as a mixture of two or more. Representative examples of the compound include compounds represented by the following formulas.

The chemically amplified resist composition of the present invention contains an acid generator that generates an acid by the action of radiation, and utilizes the catalytic action of the acid generated from the acid generator in the irradiated area.
Specifically, the acid generated in the radiation-irradiated part is diffused by a subsequent heat treatment (post exposure bake) to cleave the protective group such as a resin and to regenerate the acid, thereby making the radiation-irradiated part alkaline. It will solubilize.

In the present invention, the resin itself is insoluble or hardly soluble in an aqueous alkali solution, but a resin that becomes soluble in an aqueous alkali solution by the action of an acid has a protective group that can be cleaved by the action of an acid, and is itself an aqueous alkali solution. Although it is insoluble or hardly soluble in water, it may be a resin which becomes soluble in an aqueous alkali solution after the protective group is cleaved by the action of an acid.
The resin may be, for example, one obtained by introducing a protecting group which can be cleaved by the action of an acid into an alkali-soluble resin.
Examples of the alkali-soluble resin include an alkali-soluble resin having a phenol skeleton and an alkali-soluble resin having a (meth) acrylate ester skeleton and having an alicyclic ring and a carboxyl group on the alcohol side of the ester. Specifically, a polyvinyl phenol resin, a polyisopropenyl phenol resin, a resin in which a part of the hydroxyl group of the polyvinyl phenol resin or the polyisopropenyl phenol resin is alkyl-etherified, a vinyl phenol or isopropenyl phenol and another polymerizable resin. A copolymer resin with a saturated compound, a polymer of an alicyclic ester of (meth) acrylic acid, a resin having a carboxyl group in the alicyclic ring, an alicyclic ester of (meth) acrylic acid, ) Copolymer resins with acrylic acid.
Such a group which has an ability to inhibit dissolution in an aqueous alkali solution but is unstable to an acid can be any of various known protecting groups. Groups in which a quaternary carbon is bonded to an oxygen atom, such as tert-butyl, tert-butoxycarbonyl and tert-butoxycarbonylmethyl; methoxymethyl, ethoxymethyl, 1-ethoxyethyl, 1-isobutoxyethyl, 1-iso Propoxyethyl, 1-ethoxypropyl, tetrahydro-2-pyranyl, tetrahydro-2-furyl, 1- (2-methylpropoxy) ethyl, 1- (2-methoxyethoxy) ethyl, 1- (2-acetoxyethoxy) ethyl, Acetal-type groups such as 1- [2- (1-adamantyloxy) ethoxy] ethyl and 1- [2- (1-adamantancarbonyloxy) ethoxy] ethyl; isobornyl, 1- (1-adamantyl) -1- Alkyl, 3-oxocyclohexyl, 4-methyltetrahydro 2-pyrone-4-yl (derived from mevalonic lactone) and 2-methyl-2-adamantyl, etc. residues of non-aromatic cyclic compounds such as 2-ethyl-2-adamantyl.
These groups substitute for the hydrogen atom of the phenolic hydroxyl group or the hydrogen atom of the carboxyl group.
These protective groups can be introduced into an alkali-soluble resin having a phenolic hydroxyl group or a carboxyl group by a known protective group introduction reaction. The above resin can also be obtained by copolymerization using an unsaturated compound having such a group as one monomer.

  Among such monomers, when a group having a bulky group containing an alicyclic group such as 1- (1-adamantyl) -1-alkylalkyl is used in combination as a group that is cleaved by the action of an acid, the resolution is further improved. It is preferable because it is excellent. Examples of the monomer containing such a bulky group include 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate, 2-alkyl-2-adamantyl 5-norbornene-2-carboxylate, and 5-norbornene- 2-carboxylate 1- (1-adamantyl) -1-alkylalkyl and the like.

Next, the acid generator in the composition of the present invention will be described.
The acid generator can be any of various compounds that generate an acid by irradiating the substance itself or a resist composition containing the substance with radiation. For example, onium salts, halogenated alkyltriazine compounds, disulfone compounds, compounds having a diazomethanesulfonyl skeleton, sulfonic acid ester compounds and the like can be mentioned. Examples of the onium salt include an onium salt having one or more nitro groups in the anion, and an onium salt having one or more ester groups in the anion.
Specific examples of such an acid generator are as follows.

Diphenyliodonium trifluoromethanesulfonate,
4-methoxyphenylphenyliodonium hexafluoroantimonate,
4-methoxyphenylphenyliodonium trifluoromethanesulfonate,
Bis (4-tert-butylphenyl) iodonium tetrafluoroborate,
Bis (4-tert-butylphenyl) iodonium hexafluorophosphate,
Bis (4-tert-butylphenyl) iodonium hexafluoroantimonate,
Bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate,

Triphenylsulfonium hexafluorophosphate,
Triphenylsulfonium hexafluoroantimonate,
Triphenylsulfonium trifluoromethanesulfonate,
4-methoxyphenyldiphenylsulfonium hexafluoroantimonate,
4-methoxyphenyldiphenylsulfonium trifluoromethanesulfonate,
p-tolyldiphenylsulfonium trifluoromethanesulfonate,
p-tolyldiphenylsulfonium perfluorobutanesulfonate,
p-tolyldiphenylsulfonium perfluorooctanesulfonate,
2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate,
4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate,
4-phenylthiophenyldiphenylsulfonium hexafluorophosphate,
4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate,
1- (2-naphthoylmethyl) thiolanium hexafluoroantimonate,
1- (2-naphthoylmethyl) thiolanium trifluoromethanesulfonate,
4-hydroxy-1-naphthyldimethylsulfonium hexafluoroantimonate,
4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate,
Cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate,
Cyclohexylmethyl (2-oxocyclohexyl) sulfonium perfluorobutanesulfonate,
Cyclohexylmethyl (2-oxocyclohexyl) sulfonium perfluorooctanesulfonate,
2-oxo-2-phenylethyl thiacyclopentanium trifluoromethanesulfonate,
2-oxo-2-phenylethyl thiacyclopentanium perfluorobutanesulfonate,
2-oxo-2-phenylethyl thiacyclopentanium perfluorooctanesulfonate

2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine,
2,4,6-tris (trichloromethyl) -1,3,5-triazine,
2-phenyl-4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-chlorophenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxy-1-naphthyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (benzo [d] [1,3] dioxolan-5-yl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (3,4,5-trimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (3,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (2,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (2-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-butoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-pentyloxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,

Diphenyl disulfone,
Di-p-tolyl disulfone,
Bis (phenylsulfonyl) diazomethane,
Bis (4-chlorophenylsulfonyl) diazomethane,
Bis (p-tolylsulfonyl) diazomethane,
Bis (4-tert-butylphenylsulfonyl) diazomethane,
Bis (2,4-xylylsulfonyl) diazomethane,
Bis (cyclohexylsulfonyl) diazomethane,
(Benzoyl) (phenylsulfonyl) diazomethane,

1-benzoyl-1-phenylmethyl p-toluenesulfonate (commonly called benzoin tosylate),
2-benzoyl-2-hydroxy-2-phenylethyl p-toluenesulfonate (commonly called α-methylol benzoin tosylate),
1,2,3-benzenetriyl trismethanesulfonate,
2,6-dinitrobenzyl p-toluenesulfonate,
2-nitrobenzyl p-toluenesulfonate,
4-nitrobenzyl p-toluenesulfonate,

N- (phenylsulfonyloxy) succinimide,
N- (trifluoromethylsulfonyloxy) succinimide,
N- (trifluoromethylsulfonyloxy) phthalimide,
N- (trifluoromethylsulfonyloxy) -5-norbornene-2,3-dicarboximide;
N- (trifluoromethylsulfonyloxy) naphthalimide,
N- (10-camphorsulfonyloxy) naphthalimide and the like.

  In the resist composition of the present invention, by adding an organic basic compound as a quencher, it is possible to improve the performance deterioration due to the deactivation of an acid due to withdrawal after exposure. As the organic base compound, a nitrogen-containing basic organic compound is particularly preferred. Specific examples of such a nitrogen-containing basic organic compound include amines represented by the following formulas.

、

、

、

、

、

、

、

、

、

,

,

,

,

,

,

,

,

,

、

,

In the formula, T ¹ , T ² and T ⁷ each independently represent hydrogen, alkyl, cycloalkyl or aryl. At least one of the hydrogen atoms on the alkyl, cycloalkyl or aryl may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms. The alkyl preferably has about 1 to 6 carbon atoms, the cycloalkyl preferably has about 5 to 10 carbon atoms, and the aryl preferably has about 6 to 10 carbon atoms.
T ³ , T ⁴ and T ⁵ each independently represent hydrogen, alkyl, cycloalkyl, aryl or alkoxy. At least one of the hydrogen atoms on the alkyl, cycloalkyl, aryl, or alkoxy may be each independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms. The alkyl preferably has about 1 to 6 carbon atoms, the cycloalkyl preferably has about 5 to 10 carbon atoms, the aryl preferably has about 6 to 10 carbon atoms, and the alkoxy has 1 to 6 carbon atoms. About 6 is preferable.
T ⁶ represents alkyl or cycloalkyl. At least one hydrogen atom on the alkyl or cycloalkyl may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms. The alkyl preferably has about 1 to 6 carbon atoms, and the cycloalkyl preferably has about 5 to 10 carbon atoms.
A represents alkylene, carbonyl, imino, sulfide or disulfide. The alkylene preferably has about 2 to 6 carbon atoms.
In T ^{1 to} T ⁷ , any of T ^{1 to} T ⁷ that can have both a linear structure and a branched structure may be used.
However, none of T ¹ , T ² and T ⁷ in the compound of the formula [3] is a hydrogen atom.
T ^{8 to} T ¹⁰ may be the same or different and include a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aminoalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms or 6 Represents up to 20 substituted or unsubstituted aryl groups, wherein T ⁸ and T ⁹ may be bonded to each other to form a ring.

  Specific examples of such a compound include hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, 1- or 2-naphthylamine, and ethylenediamine. , Tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'- Diethyldiphenylmethane, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, N-methylaniline, piperidine, diphenylamine, triethylamine, trimethylamine, tripropylamine, tributylamine , Tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine , Methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, N, N-dimethylaniline, 2,6-isopropylaniline, imidazole, pyridine, -Methylpyridine, 4-methylimidazole, bipyridine, 2,2'-dipyridylamine, di-2-pyridylketone, 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,3-di (4-pyridyl) propane, 1,2-bis (2-pyridyl) ethylene, 1,2-bis (4-pyridyl) ethylene, 1,2-bis (4-pyridyloxy) ethane, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 1,2-bis (4-pyridyl) ethylene, 2,2'-dipicolylamine, 3,3'-dipicolylamine, tetramethylammonium hydroxide , Tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra-n-hexylammonium hydroxide, tetra-n- Octyl ammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethylammonium hydroxide, choline, N-methylpyrrolidone, dimethylimidazole and the like can be mentioned.

  Furthermore, a hindered amine compound having a piperidine skeleton as disclosed in JP-A-11-52575 can be used as the quencher.

The resist composition of the present invention preferably contains an acid generator in the range of 0.1 to 20% by weight based on the weight of the resin.
When a basic compound is used as the quencher, it is preferably contained in the range of 0.001 to 2% by weight, based on the resin weight of the resist composition, and in the range of 0.01 to 1% by weight. More preferably, it is contained.
The composition of the present invention may contain a small amount of various additives such as a sensitizer, a dissolution inhibitor, another resin, a surfactant, a stabilizer, and a dye, if necessary.

The resist composition of the present invention usually becomes a resist liquid composition in a state where the above components are dissolved in a solvent, and is applied on a substrate such as a silicon wafer according to a conventional method such as spin coating. The solvent used here may be any as long as it dissolves each component, has an appropriate drying rate, and gives a uniform and smooth coating film after the solvent evaporates. Solvents generally used in this field are used. Can.
For example, glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate, acetone, methyl isobutyl ketone, 2-heptanone And ketones such as cyclohexanone, and cyclic esters such as γ-butyrolactone. These solvents can be used alone or in combination of two or more.

The resist film applied on the substrate and dried is subjected to an exposure treatment for patterning, and then subjected to a heat treatment for promoting a deprotection group reaction, and then developed with an alkali developer. The alkaline developer used here can be various alkaline aqueous solutions used in this field, but generally, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) is used. Often used.
Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is defined by the appended claims, and includes all modifications within the scope and meaning equivalent to the claims.

  Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, parts indicating the amount of use are based on weight unless otherwise specified. The weight average molecular weight is a value determined by gel permeation chromatography using polystyrene as a standard.

Resin synthesis example 1 (synthesis of resin A1)
2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate, and α-methacryloyloxy-γ-butyrolactone were mixed at a molar ratio of 5: 2.5: 2.5 (20.0 parts: (9.5 parts: 7.3 parts), and methylisobutyl ketone was added in an amount of 2 times the weight of all monomers to prepare a solution. Thereto, azobisisobutyronitrile as an initiator was added at 2 mol% based on the total amount of monomers, and the mixture was heated at 80 ° C. for about 8 hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane to precipitate was performed three times to purify. As a result, a copolymer having a weight average molecular weight of about 9,200 was obtained. This copolymer has units represented by the following formula, and is referred to as a resin A1.

Resin Synthesis Example 2 (Synthesis of 2-ethyl-2-adamantyl methacrylate / p-acetoxystyrene copolymer (20:80))
A flask was charged with 39.7 g (0.16 mol) of 2-ethyl-2-adamantyl methacrylate, 103.8 g (0.64 mol) of p-acetoxystyrene and 265 g of isopropanol, and heated to 75 ° C. under a nitrogen atmosphere. Warmed up. A solution prepared by dissolving 11.05 g (0.048 mol) of dimethyl 2,2′-azobis (2-methylpropionate) in 22.11 g of isopropanol was added dropwise to the solution. After aging at 75 ° C. for about 0.3 hours and under reflux for about 12 hours, the mixture was diluted with acetone, and the reaction solution was poured into a large amount of methanol to precipitate a polymer, which was separated by filtration.
The obtained copolymer of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene was 250 g (however, the weight of the wet cake containing methanol).

Resin Synthesis Example 3 (Synthesis of 2-ethyl-2-adamantyl methacrylate / p-hydroxystyrene copolymer (20:80), resin A2)
A flask was charged with 250 g of a copolymer of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene (20:80), 10.3 g (0.084 mol) of 4-dimethylaminopyridine and 202 g of methanol, and refluxed. Aged for 20 hours below. After cooling, the reaction solution was neutralized with 7.6 g (0.126 mol) of glacial acetic acid and precipitated by pouring into a large amount of water. The precipitated polymer was separated by filtration, dissolved in acetone, and then poured into a large amount of water to cause precipitation to be repeated three times in total for purification.
The obtained copolymer of 2-ethyl-2-adamantyl methacrylate and p-hydroxystyrene was 95.9 g. The weight average molecular weight was about 8600, the degree of dispersion was 1.65 (GPC method: in terms of polystyrene), and the copolymerization ratio was about 20:80 by a nuclear magnetic resonance ( ^13C -NMR) spectrometer. . This resin is referred to as resin A2.

Next, in addition to each of the resins obtained in the above resin synthesis examples, a resist composition was prepared using the following raw materials and evaluated.

Ｄ２：下記化合物、分子量２９４
200nm波長でのモル吸光係数＝12000 リットル/(mol*cm)

Ｄ３：以下のようにして合成した。
添加剤合成例１（添加剤Ｄ３の合成）
(1a) メタアクリル酸２−エチル−２−アダマンチルとｐ−アセトキシスチレン共重合体（３０：７０）の合成
フラスコに、メタアクリル酸２−エチル−２−アダマンチル５９.６ｇ（0.２４モル）とｐ−アセトキシスチレン９０.８ｇ（０.５６モル）とイソプロパノール２７９ｇを仕込んで窒素置換をし、７５℃まで昇温した。その溶液に、ジメチル２‘２−アゾビス（２−メチルプロピオネート）１１.０５ｇ（０.０４８モル）をイソプロパノール２２.１１ｇに溶かしてから滴下した。７５℃で約０.３時間、還流下で約１２時間熟成した後、アセトンで希釈し、メタノールにチャージし、晶析させ、濾過により結晶を取り出した。得られたメタアクリル酸２−エチル−２−アダマンチルとｐ−アセトキシスチレン共重合体の粗結晶は２５０ｇであった。
(1b) メタアクリル酸２−エチル−２−アダマンチルとｐ−ヒドロキシスチレン共重合体（３０：７０）の合成
フラスコに、(1a)で得られたメタアクリル酸２−エチル−２−アダマンチルとｐ−アセトキシスチレン共重合体（３０：７０）の粗結晶２５０ｇと４−ジメチルアミノピリジン１０.８ｇ（０．０８８ モル）とメタノール２３９ｇを仕込んで、還流下、２０時間熟成した。冷却後、氷酢酸８.０ｇ（０．１３３モル）で中和し、水にチャージし、晶析させ、濾過により結晶を取り出した。その後、結晶をアセトンに溶かし、水にチャージし、晶析させ、濾過により結晶を取り出し、この操作を計３回繰り返した後、得られた結晶を乾燥した。得られたメタアクリル酸２−エチル−２−アダマンチルとｐ−ヒドロキシスチレン共重合体の結晶は１０２.８ｇであった。また、重量平均分子量は約８２００、分散度１.６８（ＧＰＣ法：ポリスチレン換算）であり、共重合比は核磁気共鳴（^１３Ｃ−ＮＭＲ）分光計により、約３０：７０と求められた。この樹脂を添加剤D3とする。
＜溶剤＞
Ｅ１：プロピレングリコールモノメチルエーテルアセテート １０４．５部
γ−ブチロラクトン ５．５部
Ｅ２：プロピレングリコールモノメチルエーテルアセテート １３０部 <Acid generator>
B1: tris (4-tert-butylphenyl) sulfonium trifluoromethanesulfonate B2: 4-methylphenyldiphenylsulfonium trifluoromethanesulfonate B3: triphenylsulfonium triisopropylbenzenesulfonate B4: bis (tert-butylsulfonyl) diazomethane <quencher >
C1: 2,6-diisopropylaniline,
<Additive: Compound having an optical absorption at 190 to 260 nm that forms an aromatic ring>
D1: mixture of the following compounds, molecular weight: 254
Molar extinction coefficient at 200 nm wavelength = 23000 liters / (mol * cm)
Molar extinction coefficient at 250 nm wavelength = 35600 liters / (mol * cm)

D2: The following compound, molecular weight 294
Molar extinction coefficient at 200 nm wavelength = 12000 liters / (mol * cm)

D3: Synthesized as follows.
Additive Synthesis Example 1 (Synthesis of Additive D3)
(1a) Synthesis of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene copolymer (30:70) In a flask, 59.6 g (0.24 mol) of 2-ethyl-2-adamantyl methacrylate was placed. Then, 90.8 g (0.56 mol) of p-acetoxystyrene and 279 g of isopropanol were charged, the atmosphere was replaced with nitrogen, and the temperature was raised to 75 ° C. To the solution, 11.05 g (0.048 mol) of dimethyl 2'2-azobis (2-methylpropionate) was dissolved in 22.11 g of isopropanol, and then added dropwise. After aging at 75 ° C. for about 0.3 hours and under reflux for about 12 hours, the mixture was diluted with acetone, charged into methanol, crystallized, and crystals were taken out by filtration. Crude crystals of the obtained 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene copolymer were 250 g.
(1b) Synthesis of 2-ethyl-2-adamantyl methacrylate and p-hydroxystyrene copolymer (30:70) In a flask, 2-ethyl-2-adamantyl methacrylate obtained in (1a) and p 250 g of crude crystals of an acetoxystyrene copolymer (30:70), 10.8 g (0.088 mol) of 4-dimethylaminopyridine and 239 g of methanol were charged and aged for 20 hours under reflux. After cooling, the mixture was neutralized with 8.0 g (0.133 mol) of glacial acetic acid, charged into water, crystallized, and crystals were taken out by filtration. Thereafter, the crystals were dissolved in acetone, charged with water, crystallized, and the crystals were taken out by filtration. This operation was repeated three times in total, and the obtained crystals were dried. The crystals of the obtained 2-ethyl-2-adamantyl methacrylate and p-hydroxystyrene copolymer weighed 102.8 g. The weight average molecular weight was about 8200, the degree of dispersion was 1.68 (GPC method: converted to polystyrene), and the copolymerization ratio was determined to be about 30:70 by a nuclear magnetic resonance ( ^13C -NMR) spectrometer. This resin is referred to as an additive D3.
<Solvent>
E1: Propylene glycol monomethyl ether acetate 104.5 parts γ-butyrolactone 5.5 parts E2: Propylene glycol monomethyl ether acetate 130 parts

Examples 1 to 6 and Comparative Examples 1 to 3
The following components were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist solution.

Resin (type and amount are listed in Table 1)
Acid generator (type and amount are listed in Table 1)
Quencher (type and amount are listed in Table 1)
Additives (types and amounts are listed in Table 1)
Solvent (type and amount are listed in Table 1)

The resist solution was spin-coated on a silicon wafer so that the film thickness after drying was 0.185 μm. After the application of the resist solution, prebaking was performed on a direct hot plate at a temperature shown in the column “PB” in Table 1 for 60 seconds. The exposure amount was adjusted step by step using an ArF excimer stepper (“NSR ArF” manufactured by Nikon Corporation, NA = 0.55, annular illumination (σout = 0.75, σin = 0.50)) on each of the wafers on which the resist film was formed. The line-and-space pattern was exposed while changing the pattern. After the exposure, post-exposure baking was performed for 60 seconds on the hot plate at the temperature shown in the column of “PEB” in Table 1, and paddle development was performed for 60 seconds with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide. Was. The bright field pattern after development on the organic anti-reflection film substrate was observed with a scanning electron microscope. The results are shown in Table 2.
The bright field pattern referred to here is that the outer frame is a chrome layer (light-shielding layer), and a chrome layer (light-shielding layer) is formed in a line on the inside of the frame based on the glass surface (light-transmitting portion). This is a pattern obtained by exposure and development through a reticle. Therefore, after exposure and development, the resist layer around the line and space pattern is removed, and a resist layer corresponding to an outer frame remains outside the pattern.
The resist solution was spin-coated on a quartz wafer so that the film thickness after drying was 0.185 μm. After the application of the resist solution, prebaking was performed on a direct hot plate at a temperature shown in the column “PB” in Table 1 for 60 seconds. The transmittance of each wafer on which the resist film was formed in this manner was measured using a spectrophotometer [“DU-640” manufactured by Beckman, and a quartz wafer as a blank. ].
The molar extinction coefficient was measured by dissolving the compound in CH ₃ CN and using a quartz cell having an optical path length of 1 cm with a spectrophotometer [Hitachi U-3500].
The molar extinction coefficient was calculated by dividing the absorbance (unit: 1 / cm) obtained by the spectrophotometer by the molar concentration (unit: Mol / liter). The unit of the molar extinction coefficient is liter / (mol * cm).

Effective sensitivity: The exposure was such that a 0.14 μm line and space pattern was 1: 1.
Resolution: Displayed with the minimum dimension of the line and space pattern separated by the exposure amount of the effective sensitivity.
Pattern Wall Smoothness: Observation of the dense line and space pattern (line: space = 1: 1) and isolated slit pattern wall surfaces with a scanning electron microscope. Those that did not exist were judged as x.
Transmittance: Transmittance of a film coated on a quartz wafer at a thickness of 0.185 μm with respect to light of 193 nm.

[Table 1]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example No. Resin Acid generator Quencher Additive Solvent PB PEB
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example 1 A1 / 10 part B1 / 0.55 part C1 / 0.06 part D1 / 0.3 part E1 100 ° C 120 ° C
Example 2 A1 / 10 part B1 / 0.55 part C1 / 0.06 part D1 / 0.3 part E1 115 ° C 120 ° C
Example 3 A1 / 10 part B1 / 0.55 part C1 / 0.03 part D1 / 0.4 part E1 115 ° C 120 ° C
Example 4 A1 / 10 part B2 / 0.40 part C1 / 0.03 part D1 / 0.2 part E1 115 ° C 120 ° C
Example 5 A1 / 10 part B1 / 0.55 part C1 / 0.06 part D2 / 0.3 part E1 100 ° C 120 ° C
Example 6 A1 / 10 part B1 / 0.55 part C1 / 0.06 part D2 / 0.3 part E1 115 ° C 120 ° C
────────────────────────────────────
Comparative Example 1 A1 / 10 part B1 / 0.55 part C1 / 0.03 part-E1 115 ° C 120 ° C
Comparative Example 2 A1 / 10 part B2 / 0.40 part C1 / 0.03 part D3 / 0.2 part E1 115 ° C 120 ° C
Comparative Example 3 A1 / 10 part B2 / 0.40 part C1 / 0.03 part D3 / 0.5 part E1 115 ° C 120 ° C
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[Table 2]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example No. Effective sensitivity Resolution Pattern wall transmittance
(mJ / cm ² ) (μm) Smoothness (%)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example 1 17.5 0.14 ○ 54.8
Example 2 18.5 0.14 ○ 54.8
Example 3 9.5 0.13 ○ 52.5
Example 4 6.0 0.13 ○ 57.7
Example 5 18.0 0.13 ○ 61.4
Example 6 18.0 0.13 ○ 61.4
───────────────────────────────
Comparative Example 1 7.5 0.13-66.6
Comparative Example 2 5.0 0.13 × 57.0
Comparative Example 3 5.5 0.14 × 46.9
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Examples 7 to 8 and Comparative Example 4
The following components were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist solution.

Resin A2 4.3 parts / D3 5.7 parts Acid generator B3 0.33 parts / B4 0.33 parts Quencher C1 0.04 parts Additives D1 Amount is as shown in Table 3 Solvent E2 132 parts

The above resist solution was spin-coated on a silicon wafer so that the film thickness after drying was 0.25 μm. After the application of the resist solution, prebaking was performed on a direct hot plate at 110 ° C. for 60 seconds. A KrF excimer stepper (“NSR-2205EX12B” manufactured by Nikon Corporation, NA = 0.55, annular illumination (σout = 0.8, σin = 0.53)) was used on each wafer on which the resist film was formed. The line and space pattern was exposed while changing the exposure amount stepwise. After the exposure, post-exposure baking was performed on a hot plate at 120 ° C. for 60 seconds, and paddle development was performed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 60 seconds. The bright field pattern after development on the organic anti-reflection film substrate was observed with a scanning electron microscope. The results are shown in Table 4.
The bright field pattern referred to here is that the outer frame is a chrome layer (light-shielding layer), and a chrome layer (light-shielding layer) is formed in a line on the inside of the frame based on the glass surface (light-transmitting portion). This is a pattern obtained by exposure and development through a reticle. Therefore, after exposure and development, the resist layer around the line and space pattern is removed, and a resist layer corresponding to an outer frame remains outside the pattern.
The resist solution was spin-coated on a quartz wafer so that the film thickness after drying was 0.28 μm. After the application of the resist solution, prebaking was performed on a direct hot plate at 110 ° C. for 60 seconds. The transmittance of each wafer on which the resist film was formed in this manner was measured using a spectrophotometer [“DU-640” manufactured by Beckman, and a quartz wafer as a blank. ].
The molar extinction coefficient was determined in the same manner as in Example 1.

Effective sensitivity: Displayed at an exposure amount at which a 0.24 μm line and space pattern becomes 1: 1.
Resolution: It was determined in the same manner as in Example 1.
Smoothness of pattern wall surface: A dense line and space pattern (line: space = 1: 1) and a wall surface of an isolated slit pattern were observed with a scanning electron microscope. Those that did not exist were judged as x.
Transmittance: Transmittance of a film applied on a quartz wafer to light of 248 nm per 0.25 μm thickness.

[Table 3]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example No. Amount of additive━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example 7 0.26 parts Example 8 0.50 parts
Comparative Example 4 None

[Table 4]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example No. Effective sensitivity Resolution Pattern wall transmittance
(mJ / cm ² ) (μm) Smoothness (%)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example 7 16.5 0.15 ○ 74
Example 8 18.0 0.15 ○ 66
───────────────────────────────
Comparative Example 4 13.5 0.15-86
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  The positive resist composition of the present invention has improved the smoothness of the pattern wall surface due to the standing wave effect, particularly when applied to a highly reflective substrate or caused by thinning the resist film thickness. It is suitably used for excimer laser lithography such as ArF.

Claims (5)

  It itself is insoluble or hardly soluble in an aqueous alkali solution, but has a resin, an acid generator, and an aromatic ring that are soluble in an aqueous alkali solution by the action of an acid, has a molecular weight of 1,000 or less, and has a wavelength range of 190 nm to 260 nm. A compound having a light absorption coefficient of 1000 liters / (mol * cm) or more, wherein the compound is in the range of 0.01 to 20% by weight with respect to the resin. -Type positive resist composition.   2. A compound having an aromatic ring, having a molecular weight of 1,000 or less, and having a light absorption coefficient of 1000 liter / (mol * cm) or more in a wavelength region of 190 nm to 200 nm. A composition as described.   2. A compound having an aromatic ring, having a molecular weight of 1,000 or less, and having a light absorption in a wavelength region of 240 nm to 260 nm having a molar extinction coefficient of 1000 liter / (mol * cm) or more. A composition as described. A compound having light absorption in a wavelength region of 190 nm to 260 nm is represented by the following formula (I)

(Wherein, R ₁ , R ₂ , R _3, R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each independently a hydrogen atom, an alkyl group which may be branched, or a branched atom. Represents an alkoxy group or a hydroxyl group, wherein X ₁ represents a sulfur atom, an oxygen atom, or a CH ₂ group.
And a compound represented by the following formula (II):

(In the formula, R ₉ , R ₁₀ , R _11, R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ and R ₁₆ are each independently a hydrogen atom, an optionally branched alkyl group, or an optionally branched group. Represents an alkoxy group, a carboxylate group, a cyano group, an amino group, a phenyl group, a carboxyl group, a benzoyl group, a hydroxyl group, or a halogen atom, wherein any carbon atom of the alkyl group or the alkoxy group is substituted with a nitrogen atom The structure containing a double bond (excluding a benzene ring) in the formula may be any of a cis-type structure and a trans-type structure.)
The composition according to any one of claims 1 to 3, which is at least one member selected from the group consisting of compounds represented by the following formula: The composition according to any one of claims 1 to 4, further comprising an organic base compound as a quencher.