JP2001166475A - Resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition excellent in sensitivity and resolution and having such superior characteristics as to give good profile and a high rate of a residual film. SOLUTION: The resist composition contains a resin component containing a polymer having a substituted styrene unit of formula I (where R is an optionally substituted 6-20C saturated hydrocarbon residue; A is a direct bond, >C=O or >SO2; and R1 is H, a 1-4C alkyl, a 1-4C alkoxy, alkoxycarbonyl having 2-5 total C atoms, acyl having 1-5 total C atoms, acyloxy having 1-5 total C atoms, nitro, cyano, F, Cl or Br) and an acid generating agent. The substituted styrene unit is present in a proportion of 0.1-10 wt.% to the total solid content of the resist.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a resist composition using a specific resin.

[0002]

2. Description of the Related Art In recent years, with the increase in the degree of integration of integrated circuits, submicron pattern formation has been required. Under these circumstances, excimer laser lithography
Attention has been paid to the possibility of manufacturing DRAMs (dynamic random access memories) from 4M to 1G. As a resist suitable for such an excimer laser lithography process, a so-called chemically amplified resist utilizing the chemical amplification effect of an acid catalyst has been put to practical use. For example, a chemically amplified negative resist generates an acid from an acid generator by the action of high energy rays such as electromagnetic waves, and crosslinks and cures the alkali-soluble resin in the high energy ray irradiated area by the action of this and a crosslinking agent. Thus, the solubility in an alkali developing solution is reduced. On the other hand, acid generation does not occur in the portion where the high energy beam is not irradiated, so that the solubility of the portion in the alkali developing solution is maintained. Based on such a mechanism, formation of a resist film,
By patterning irradiation and alkali development, a negative pattern is obtained.

As a resin for a chemically amplified resist, polyhydroxystyrene, also known as polyvinylphenol, has been frequently used. However, since polyhydroxystyrene has too high a solubility in an alkali developer, there is a problem that sufficient sensitivity and resolution cannot be obtained. To solve such a problem, Japanese Patent Application Laid-Open
JP-A-295220 and JP-A-10-69082 disclose the use of polyhydroxystyrene in which a phenolic hydroxyl group is partially alkyl etherified. By using such partially alkylated polyhydroxystyrene, sensitivity and resolution can be improved.
Further improvement has been desired, and further improvement has been desired in the profile (pattern shape) and the residual film ratio after development.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resist composition having excellent characteristics, such as excellent sensitivity and resolution, and a good profile and high residual film ratio. The present inventors have conducted intensive studies to achieve such an object, and as a result, have found that excellent results can be obtained by using a polymer having a specific unit as a resin component. Reached.

[0005]

That is, the present invention provides the following formula (I)

[0006]

[Wherein, R represents an optionally substituted saturated hydrocarbon residue having 6 to 20 carbon atoms, and A represents a direct bond, carbonyl (> C ＝ O) or sulfonyl (> SO ₂ ). , R ¹ is hydrogen, alkyl having 1 to 4 carbons, 1 to 1 carbons
4 alkoxy, alkoxycarbonyl having 2 to 5 carbon atoms, acyl having 1 to 5 carbon atoms, acyloxy having 1 to 5 carbon atoms, nitro, cyano, fluorine, chlorine or bromine. Wherein the substituted styrene unit represented by the above formula (I) is present in an amount of 0.1 to 10% by weight based on the total solids in the resist. A resist composition is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the above formula (I), R represents a saturated hydrocarbon residue which may be substituted. The saturated hydrocarbon residue referred to herein includes, for example, linear or branched alkyl, cycloalkyl, bicycloalkyl, tricycloalkyl, cycloalkylalkyl, bicycloalkylalkyl, tricycloalkylalkyl, and furthermore And a group in which a ring is formed at an arbitrary position, such as a group in which an alkyl is bonded to a cyclic portion. The saturated hydrocarbon residue may have a carbon number in the range of 6 to 20, but preferably has a carbon number in the range of 6 to 12. Examples of the group that can be substituted with such a saturated hydrocarbon residue include, for example, alkoxy having 1 to 4 carbon atoms, alkoxycarbonyl having 2 to 5 carbon atoms, acyl having 1 to 5 carbon atoms, and total carbon number. Examples thereof include 1 to 5 acyloxy, phenyl, phenoxy, oxo (= O), fluorine, and chlorine. Specific examples of alkoxy include methoxy, ethoxy, propoxy, butoxy and the like, and specific examples of alkoxy in alkoxycarbonyl are also the same, and specific examples of acyl include formyl, acetyl, propionyl, butyryl, valeryl, pivaloyl And the like, and the same applies to specific examples of acyl in acyloxy.

Specific examples of R include hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, cyclohexyl, cyclohexylmethyl, 2-
Norbornylmethyl, 2-oxo-7,7-dimethylbicyclo [2.2.1] -1-heptylmethyl and the like can be mentioned. Among them, alkyl having 6 to 12 carbon atoms, cyclohexyl, cyclohexylmethyl, 2-norbornylmethyl, 2-oxo-7,7-dimethylbicyclo [2.2.1] -1-heptylmethyl and the like are preferable.

R ¹ in the formula (I) is hydrogen, carbon number 1
Alkyl having 4 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, alkoxycarbonyl having 2 to 5 carbon atoms, acyl having 1 to 5 carbon atoms, acyloxy having 1 to 5 carbon atoms, nitro, cyano,
It can be fluorine, chlorine or bromine, but is generally preferably hydrogen. Further, in the formula (I), the group corresponding to -OAR is an o- of a benzene ring hanging from the polymer main chain.
It can be located at any of the n-, m-, and p-positions, but is generally located at the p-position from the viewpoint of the raw material.

The polymer having a substituted styrene unit represented by the formula (I) can be produced, for example, by the following method. That is, the following formula (II)

[0012]

(Wherein R ¹ is as defined above), and a polymer having an optionally substituted hydroxystyrene unit represented by the following formula (III):

[0014]

(Wherein R ¹ is as defined above), or a homopolymer of hydroxystyrene optionally substituted with a nucleus, or one or more of hydroxystyrene and another polymerizable vinyl compound. With the following formulas (IV) to (VIII)

R ² SO ₂ O—R (IV) IR (V) XC ((O) R (VI) RC (＝ O) —OC (＝ O) R (VII) X —SO ₂ R (VIII)

(Wherein R ² represents methyl, trifluoromethyl, phenyl or p-tolyl, X represents fluorine, chlorine, bromine or iodine, and R is as defined above) With the compound of formula (I)
A polymer having the unit of the formula (I) introduced therein can be produced by a method of converting at least a part of the hydroxyl group in the unit represented by the formula (I) into a group corresponding to -OAR in the formula (I). . This reaction is usually carried out in a solvent such as ethyl acetate, propylene glycol monomethyl ether acetate or methyl isobutyl ketone in the presence of a deoxidizing agent such as potassium carbonate, triethylamine or pyridine, and the unit of the formula (II) It is advantageous to dissolve or disperse the polymer in a solvent and to carry out the reaction at a temperature of about 20 to 60 ° C.

In this reaction, a sufficient amount of any of the compounds of the formulas (IV) to (VIII) is used, and substantially all of the units of the formula (II) are substituted with the substituted styrene units of the formula (I). However, it is generally preferred that some hydroxystyrene units of formula (II) remain. Further, by using a copolymer of vinyl phenol optionally substituted with a nucleus of the formula (III) and another vinyl compound as a raw material, a unit of the formula (I) and a unit of the other vinyl compound, optionally Further, a binary or higher copolymer containing a unit of the formula (II) can be obtained. In these reactions, if a plurality of compounds included in formulas (IV) to (VIII) are allowed to act in any order, a copolymer having a plurality of units within the range of formula (I) may be obtained. it can.

Formulas (IV) to (VIII) and formula (I)
Each compound used to introduce a group corresponding to -AR therein will be described. Many of these compounds are commercially available, and if desired, can be produced according to a known method. Specific examples of the sulfonic acid ester represented by the formula (IV) include octyl p-toluenesulfonate, decyl p-toluenesulfonate, cyclohexyl p-toluenesulfonate, cyclohexylmethyl p-toluenesulfonate, p-toluenesulfonic acid 2-
Norbornylmethyl and the like. These sulfonic esters can be prepared by known methods, for example, CS Marvel and
According to the method described in VC Sekera, Org. Synth., III, 366 (1955), an acid chloride corresponding to R ² SO ₂ Cl and R
It can be synthesized by a reaction with an alcohol corresponding to OH. Specific examples of the iodide represented by the formula (V) include iodocyclohexane, iodooctane, iododecane, and the like. Specific examples of the carboxylic acid halide represented by the formula (VI) include octanoic acid chloride and the like.
Specific examples of the carboxylic acid anhydride represented by octanoic anhydride and the like, and specific examples of the sulfonic acid halide represented by the formula (VIII) include 10-camphorsulfonic acid chloride and octanesulfonic acid chloride. Can be

The sulfonic acid ester represented by the formula (IV) is converted to an acid chloride corresponding to R ² SO ₂ Cl described above and R
When synthesized by reaction with an alcohol corresponding to OH, the acid chloride as a raw material may remain slightly unreacted. Formula (IV) containing such unreacted acid chloride
When the sulfonic acid ester of the formula (II) is used for the reaction with the polymer having an optionally substituted hydroxystyrene unit of the formula (II), the group corresponding to R in the formula (IV) is mainly used. However, the acid chloride may also react with the phenolic hydroxyl group to introduce a sulfonic acid residue corresponding to R ² SO ₂ — into a part of the phenolic hydroxyl group. As described above, a polymer having a unit of the formula (I) and a sulfonic acid esterified unit having a phenolic hydroxyl group not corresponding to -AR of the same formula can be directly used in the present invention. .

Therefore, of course, part of the hydroxyl groups in the optionally substituted hydroxystyrene unit represented by the above formula (II) is converted to -OAR in the above formula (I), and one of the remaining hydroxyl groups is converted. The polymer may be a polymer whose part is modified with another group. The group modifying the hydroxyl group is represented by a group that substitutes for hydrogen of the hydroxyl group, for example, an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, and tert-butyl, 1-ethoxyethyl, 1-ethoxypropyl. , 1-isobutoxyethyl, acetal-type groups such as 2-tetrahydropyranyl, acetyl, propionyl, pivaloyl, acyl groups such as benzoyl,
Examples include sulfonic acid residues such as mesyl, phenylsulfonyl, and tosyl, and tert-butoxycarbonyl.

The polymer further comprises units of unsaturated carboxylic esters such as acrylates, methacrylates, maleates, fumarates, itaconic esters, units of styrene, units of maleic anhydride, , 3-butadiene units, acrylonitrile units, methacrylonitrile units, vinyl chloride units, vinyl acetate units, and other units derived from ethylenically unsaturated compounds. The units derived from these ethylenically unsaturated compounds are generally introduced by copolymerization.

As described above, various polymers having a substituted styrene unit contained in the above formula (I) can be produced, and this polymer has a weight average molecular weight of 2,0.
It is preferably in the range of about 00 to 32,000.
The degree of dispersion represented by the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer is as follows:
It is preferably in the range of about 1.01 to 2.0. Here, the weight average molecular weight and the number average molecular weight are values measured by gel permeation chromatography (GPC) using polystyrene as a standard.

The present invention is characterized in that a polymer having a unit in which the hydroxyl group of the optionally substituted hydroxystyrene is protected by a bulky group corresponding to -AR in the formula (I) is used. There is. The polymer having the unit of the formula (I) is effective in increasing the residual film ratio because the solubility in an alkali developing solution is reduced due to the effect of the bulky group R in the formula. In this case, the sensitivity is further improved. Such an effect can be achieved by the presence of the unit represented by the formula (I). However, if the amount is too small, it is difficult to achieve the desired effect. Since the substituted styrene unit represented by the formula (I) may have an adverse effect on other performances of the resist, the content of the substituted styrene unit may be 0.1 to 1 based on the total solids in the resist.
It is present in the range of 0% by weight. In particular, the substituted styrene unit of the formula (I) is added to the total solid content of the resist in a range of 0.5 to
More preferably, it is present in the range of 4% by weight.

As described above, in the present invention, since the substituted styrene unit of the formula (I) is present in a relatively small amount in the resist, a resin having an appropriate amount of this unit is prepared, and the unit of the formula (I) is separately prepared. It is advantageous to prepare another polymer that does not have it and combine them to form a binder resin for the resist so that the ratio of the unit of the formula (I) to the total solids in the resist falls within the above range. When a polymer having a substituted styrene unit of the formula (I) and another polymer not having the unit, particularly having no bulky group corresponding to -AR in the formula, are used in combination, the resist is used as a substrate. When a resist film is formed by coating on the upper surface, the polymer having the unit of the formula (I) tends to concentrate on the upper surface of the resist film, so that it more effectively acts to improve the residual film ratio and sensitivity.

Examples of other polymers which can be used in combination with the polymer having a substituted styrene unit of the formula (I) include, for example, novolak resins and other units which may be present together with the unit of the formula (I). Homopolymers or copolymers having various units are exemplified. For example, polyhydroxystyrene or a partially alkyl etherified product thereof is advantageously used as a resin component together with the polymer having a substituted styrene unit of the formula (I) specified in the present invention. Such a polymer having no unit of the formula (I) is also 2,000 to 32.0.
It preferably has a weight average molecular weight in the range of about 00 and a dispersity in the range of about 1.01 to 2.0.

When a polymer having no substituted styrene unit of the formula (I) is mixed with a polymer having no such unit to form a binder resin for a resist, the polymer of the formula (I) may be added to the former polymer. Can be present in a relatively large amount. For example, in a copolymer containing a unit of the formula (I) and an optionally substituted hydroxystyrene unit of the formula (II), the proportion of the unit of the formula (I) is 20 to 60.
It can be about mol%. Therefore, the former has the unit of the formula (I) and the unit of the formula (II), and the former: the latter is 20: 80-
Using a polymer present in a molar ratio of 60:40,
It is advantageous to combine with a polymer having no unit of the formula (I), for example, polyhydroxystyrene or a partially alkyl etherified product thereof to form a binder resin.

In an alkali developing type resist composition, the resin therein usually has an alkali-soluble functional group. Formula (II) with a substituted styrene unit of formula (I)
In the polymer having an optionally substituted hydroxystyrene unit of the formula (1), hydroxyphenyl in the hydroxystyrene unit of the formula (II) becomes an alkali-soluble functional group. Of course, when polyhydroxystyrene or a partially modified product such as a partially alkyl etherified product thereof is used as a resin component together with a polymer having a substituted styrene unit of the formula (I), vinyl in the polyhydroxystyrene or the partially modified product thereof is used. Hydroxyphenyl in the phenol unit will also impart alkali solubility.

Next, the acid generator, which is another component of the present invention, will be described. The acid generator may be any of those commonly used in chemically amplified resist compositions. That is, the chemically amplified resist composition generates an acid by irradiating the composition with a high-energy ray and utilizes the catalytic action of the acid. In the present invention, such a high-energy ray is also used. A compound that generates an acid upon irradiation is used as an acid generator. Here, the high energy ray is a g-line having a wavelength of 468 nm and an i-line having a wavelength of 365 nm.
X-rays, KrF excimer light having a wavelength of 248 nm, ArF excimer light having a wavelength of 198 nm, and X-rays, electron beams, ion beams, and other electromagnetic waves or beams capable of acting on molecules to cause a chemical reaction.

Examples of the acid generator include iodonium salt compounds, sulfonium salt compounds, organic halogen compounds (particularly haloalkyl-s-triazine compounds), sulfonate compounds, disulfone compounds, diazomethane compounds, and N-sulfonyloxyimide compounds. Can be The compounds included in these can be used alone or in combination of two or more, if necessary.
More specifically, examples of the acid generator include the following compounds.

(1) Iodonium salt compound 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, bis (4 -Tert-butylphenyl) iodonium
10-Camphorsulfonate, bis (4-tert-butylphenyl) iodonium p-toluenesulfonate and the like.

(2) Sulfonium salt compound Triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, 4-methoxyphenyldiphenylsulfonium hexafluoroantimonate, 4-methoxyphenyldiphenylsulfonium trifluoromethane Sulfonate, 4-methylphenyldiphenylsulfonium methanesulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate, 2,
4,6-trimethylphenyldiphenylsulfonium
Trifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-phenylthiophenyldiphenylsulfonium hexafluorophosphate, 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, 1- (2-naphthoylmethyl) thiolanium hexa Fluoroantimonate, 1- (2-
Naphthoylmethyl) thiolanium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium hexafluoroantimonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate and the like.

(3) Organohalogen compound 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 and the like.

(4) Sulfonate compound 1-benzoyl-1-phenylmethyl p-toluenesulfonate (commonly called benzoin tosylate), 2-benzoyl-2-hydroxy-2-phenylethyl p-toluenesulfonate (commonly called α-methylol benzoin toshi) Rate), 1,2,3-benzenetriyl trismethanesulfonate, 2,6-dinitrobenzyl p-toluenesulfonate, 2-nitrobenzyl p-toluenesulfonate, 4-nitrobenzyl p-toluenesulfonate and the like.

(5) Disulfone compounds Diphenyl disulfone, di-p-tolyl disulfone and the like.

(6) diazomethane compound bis (phenylsulfonyl) diazomethane, bis (4-
Chlorophenylsulfonyl) diazomethane, bis (p-
Tolylsulfonyl) diazomethane, bis (4-tert-butylphenylsulfonyl) diazomethane, bis (2,4
-Xylylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (tert-butylsulfonyl) diazomethane, (benzoyl) (phenylsulfonyl) diazomethane and the like.

(7) N-sulfonyloxyimide compound N- (ethylsulfonyloxy) succinimide, N-
(Isopropylsulfonyloxy) succinimide, N
-(Butylsulfonyloxy) succinimide, N-
(10-camphorsulfonyloxy) succinimide, 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.

Among these, preferred acid generators in combination with the resin specified in the present invention include bis (4-te
rt-butylphenyl) iodonium 10-camphorsulfonate, bis (4-tert-butylphenyl) iodonium p-toluenesulfonate, 4-methylphenyldiphenylsulfonium methanesulfonate, 4-
Methylphenyldiphenylsulfonium trifluoromethanesulfonate, bis (tert-butylsulfonyl)
Diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (p-tolylsulfonyl) diazomethane, N- (ethylsulfonyloxy) succinimide,
N- (isopropylsulfonyloxy) succinimide, N- (butylsulfonyloxy) succinimide,
N- (10-camphorsulfonyloxy) succinimide and the like can be mentioned.

In lithography using a chemically amplified resist composition, a post-exposure bake (post-exposure bake) is generally performed to progress a chemical reaction in a chain using an acid generated by the exposure as a catalyst. But,
It is known that if the time from exposure to post-exposure bake is prolonged, performance degradation accompanying acid deactivation is caused. Furthermore, when the generated acid diffuses more than necessary in the resist coating film, the chemical reaction spreads to the unexposed portion, and the performance such as the pattern shape may be deteriorated. Basic compounds, especially basic nitrogen-containing compounds, are used to prevent performance degradation due to acid deactivation associated with the withdrawal after exposure, or to control acid diffusion and suppress reactions in unexposed areas. It is known that it is effective to mix a small amount of an organic compound such as an amine as a quencher. In the present invention, it is preferable to include such a basic nitrogen-containing organic compound as a quencher.

The nitrogen-containing organic compound used for the quencher can be a primary amine, a secondary amine, a tertiary amine, an unsaturated cyclic amine, a quaternary ammonium salt, and the like. Compounds are exemplified.

(8) Primary amine hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, 1- or 2
-Naphthylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3 , 3'-diethyldiphenylmethane and the like.

(9) Secondary amine dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, N-methylaniline, piperidine, diphenylamine and the like.

(10) Tertiary amine triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentyl Amine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, Ethyldinonylamine, ethyldidecylamine, tris [2- (2-methoxyethoxy) ethyl] amine,
Triisopropanolamine, N, N-dimethylaniline and the like.

(11) Unsaturated cyclic amine imidazole, pyridine, 4-methylpyridine, 4-methylimidazole, bipyridine, 2,2'-dipyridylamine, di-2-pyridyl ketone, 1,2-di (2-pyridyl ) Ethane, 1,2-di (4-pyridyl) ethane,
1,3-di (4-pyridyl) propane, 1,2-di (2
-Pyridyl) ethylene, 1,2-di (4-pyridyl) ethylene, 1,2-bis (4-pyridyloxy) ethane,
4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipicolylamine, 3,
3'-dipicolylamine and the like.

(12) Quaternary ammonium salts such as tetraisopropylammonium hydroxide and tetrabutylammonium hydroxide.

Of these, unsaturated cyclic amines are preferred, and particularly preferred are bipyridine,
2,2'-dipyridylamine, di-2-pyridyl ketone, 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,3-di (4-pyridyl)
Propane, 1,2-di (2-pyridyl) ethylene, 1,
2-di (4-pyridyl) ethylene, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide,
Examples thereof include 2,2'-dipicolylamine and 3,3'-dipicolylamine. In addition, the basic nitrogen-containing organic compound used as the quencher is preferably one that is hard to evaporate at the temperature of the pre-bake, so that the basic nitrogen-containing organic compound remains in the resist film even after the pre-bake of the resist film formed on the substrate and exhibits an effect. Specifically, compounds having a boiling point of 150 ° C. or higher are preferred.

Further, by including a crosslinking agent,
A negatively acting resist composition can be obtained.
As used herein, the term "crosslinking agent" means a compound having an action of crosslinking a resin component by the action of an acid. As such a crosslinking agent, a compound containing a methylol group or an alkyl ether thereof is preferable, and examples thereof include compounds described in JP-A-1-293339 and JP-A-5-210239. Among them, preferred crosslinking agents include hexamethoxymethylmelamine represented by the following formula (a), tetramethoxymethylbenzoguanamine represented by the following formula (b), and tetramethoxymethylglyoxal diurein (2) represented by the following formula (c) , 4,6,8-Tetramethoxymethyl-2,4
6,8-tetraazabicyclo [3.3.0] bicyclooctane-3,7-dione).

[0048]

The resist composition of the present invention usually has the formula (I)
In total of 70 to 99.9% by weight of a resin component containing a polymer having a substituted styrene unit, and 0.1 to 2 parts by weight of an acid generator.
It is contained in the range of 0% by weight. In the case of a composition mainly composed of a resin component and an acid generator, it is preferable that the resin component be in the range of 80 to 99.9% by weight and the acid generator be in the range of 0.1 to 20% by weight. When a quencher is contained, the quencher is also used in an amount of 0.1% based on the total solid content of the resist composition.
It is preferably used in the range of 0001 to 1% by weight. Further, when a crosslinking agent is contained as a negative resist,
Similarly, based on the total solid content of the resist composition, 7
It is preferable to use 0 to 99.9% by weight, 0.1 to 20% by weight of an acid generator and 1 to 30% by weight of a crosslinking agent. Further, the resist composition of the present invention, if necessary, a sensitizer,
Various additives such as a dissolution inhibitor, a surfactant, a stabilizer, and a dye may be contained in a small amount.

The resist composition is usually prepared by mixing the above components with a solvent so as to have a total solid content of 10 to 50% by weight to form a resist solution, which is applied onto a substrate such as a silicon wafer. The solvent used here may be any solvent that dissolves each component and has an appropriate drying rate, and those commonly used in this field can be used. For example, ethyl cellosolve acetate, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, glycol ether esters such as propylene glycol monoethyl ether acetate, ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol dimethyl ether Glycols such as glycol mono- or diethers, ethyl lactate, butyl acetate, amyl acetate, ethyl pyruvate, esters such as γ-butyrolactone, ketones such as 2-heptanone, cyclohexanone, methyl isobutyl ketone, and aromatics such as xylene. Group hydrocarbons and lactams such as N-methyl-2-pyrrolidone. These solvents can be used alone or in combination of two or more.

The resist composition of the present invention can be used, for example, as follows. That is, a resist solution dissolved in a solvent as described above is applied to a substrate by a conventional method such as spin coating, dried (prebaked), subjected to an exposure treatment for patterning, and then to promote a chemical reaction. After the heat treatment, the resist pattern can be formed by developing with an alkali developing solution. The alkaline developer used here is
It may be one commonly used in this field. For example, a 1 to 10% by weight aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) is exemplified. It is also possible to add an appropriate amount of a water-soluble organic solvent such as methanol or ethanol, or a certain surfactant to these alkaline aqueous solutions.

[0052]

EXAMPLES 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, percentages and parts representing contents or amounts used are by weight unless otherwise specified. The weight average molecular weight and the degree of dispersion are values measured by gel permeation chromatography using polystyrene as a standard.

Synthesis Example 1: Production of poly (p-hydroxystyrene / p-octyloxystyrene / p-tosyloxystyrene) poly (p-hydroxystyrene) [weight average molecular weight of 4.0
00, dispersity 1.15] 100 parts were dissolved in 400 parts of acetone, and 69.6 parts of potassium carbonate and 156.9 parts of octyl p-toluenesulfonate (unreacted p-toluenesulfonic acid chloride was dissolved in about 12.3%, so that the pure content of octyl p-toluenesulfonate is about 13%.
(Equivalent to 7.6 parts), and the mixture was heated to a reflux state. Subsequently, the reflux state was maintained for 48 hours. Next, methyl isobutyl ketone was added, and this solution was washed with an aqueous oxalic acid solution, and then washed with ion-exchanged water. After washing the organic layer
0 parts, and 800 parts of propylene glycol monomethyl ether acetate was added thereto.
Concentrated. As a result, a resin solution having a solid content of 23.20% determined by a heating weight reduction method was obtained. ¹ H-
NMR measurement [270 MHz, (dimethyl sulfoxide)-
Check the broad peak 3.9ppm at d in _6], it was assigned to this peak and bound to the methylene protons on oxygen atom. Further, broad peaks were observed at 7.3 ppm and 7.6 ppm, and these peaks were assigned to the aromatic proton of the tosyl group. From the integral ratio of these protons to the aromatic protons derived from poly (p-hydroxystyrene), this resin has a molar ratio of p-hydroxystyrene unit, p-octyloxystyrene unit and p-tosyloxystyrene unit of 57%. : 37: 6. This copolymer is referred to as a resin R1.

Synthesis Example 2: Production of poly (p-hydroxystyrene / p-octyloxystyrene) 50 parts of the same poly (p-hydroxystyrene) used in Synthesis Example 1 were dissolved in 200 parts of acetone, and 50.61 parts of potassium carbonate and 66.78 parts of octyl p-toluenesulfonate were added, and the mixture was heated to a reflux state. Subsequently, the reflux state was maintained for 38 hours. Next, methyl isobutyl ketone was added, and this solution was washed with an aqueous oxalic acid solution, and then washed with ion-exchanged water. The organic layer after washing was concentrated, and 400 parts of propylene glycol monomethyl ether acetate was added thereto, and further concentrated to 177 parts. As a result, a resin solution having a solid content of 39.56% determined by a heating weight reduction method was obtained. ^{From 1} H-NMR measurement [270 MHz, in (dimethyl sulfoxide) -d ₆ ], this resin is a copolymer having a molar ratio of p-hydroxystyrene units to p-octyloxystyrene units of 53:47. Was confirmed. Resin R
Assume 2.

Synthesis Example 3: Preparation of poly (p-hydroxystyrene / p-cyclohexylmethoxystyrene) 40 parts of the same poly (p-hydroxystyrene) used in Synthesis Example 1 were dissolved in 160 parts of acetone, and 50.61 parts of potassium carbonate and 40.70 parts of cyclohexylmethyl p-toluenesulfonate were added, and the mixture was heated to a reflux state. Subsequently, the reflux state was maintained for 150 hours. Next, methyl isobutyl ketone was added, and this solution was washed with an aqueous oxalic acid solution, and then washed with ion-exchanged water. The washed organic layer was concentrated, and 320 parts of propylene glycol monomethyl ether acetate was added thereto.
Concentrated to 5 parts. As a result, a resin solution having a solid content of 34.06% as determined by a heating weight reduction method was obtained. ¹
H-NMR measurement [270 MHz, (dimethyl sulfoxide) -d # _6] Ensure broad peak 3.7ppm in, I was assigned to this peak and bound to the methylene protons on oxygen atom. From the integral ratio of this proton to the aromatic proton, this resin was found to have p-hydroxystyrene units and p-hydroxystyrene units.
When the molar ratio to the cyclohexylmethoxystyrene unit is 7
It was confirmed that the copolymer was a 1:29 copolymer. This copolymer is referred to as a resin R3.

Synthesis Example 4: Production of poly (p-hydroxystyrene / p-octanoyloxystyrene) 40 parts of the same poly (p-hydroxystyrene) used in Synthesis Example 1 were dissolved in 160 parts of acetone, and The temperature was raised to ° C. Then add 22.23 parts of triethylamine,
Further, 23.83 parts of octanoyl chloride was added dropwise over 30 minutes. Subsequently, the temperature was maintained at 40 ° C. for 3 hours. Next, methyl isobutyl ketone was added, and this solution was washed with an aqueous oxalic acid solution, and then washed with ion-exchanged water. The organic layer after washing was concentrated, 360 parts of propylene glycol monomethyl ether acetate was added thereto, and the mixture was further concentrated to 187 parts. As a result, a resin solution having a solid content of 29.44% determined by a heating weight reduction method was obtained. ¹ H-NMR measurement [270 MHz, in (acetone) -d ₆ ] confirmed a broad peak at 2.6 ppm, and this peak was assigned to a methylene proton bonded to carbonyl. From the integral ratio of this proton and aromatic proton, it was confirmed that this resin was a copolymer having a molar ratio of p-hydroxystyrene units to p-octanoyloxystyrene units of 63:37. This copolymer is referred to as a resin R4.

Next, an example in which a resist composition was prepared using the propylene glycol monomethyl ether acetate solution of the resin obtained in the above synthesis example and evaluated was shown. In addition, in addition to these resins, a resin in which a part of hydroxyl groups of poly (p-hydroxystyrene) [weight-average molecular weight: 4,000, dispersity: 1.15] synthesized by living anionic polymerization is isopropyl etherized, A resin (resin RA) having an isopropoxylation ratio of 21.6 mol% to hydroxyl groups in poly (p-hydroxystyrene) was 3
A propylene glycol monomethyl ether acetate solution containing 0.0% concentration was also used.

Example 1 The following components were mixed with about 600 parts of propylene glycol monomethyl ether acetate, including the amount brought in from the resin solution, and further filtered through a fluororesin filter having a pore diameter of 0.1 μm to obtain a resist. A liquid was prepared.

Resin RA (solid content) 100.0 parts Resin R2 (solid content) 2.5 parts Acid generator: N- (isofluorosulfonyloxy) succinimid 11.0 parts Crosslinking agent: hexamethoxymethyl melamine 5.0 parts Quencher: 1,3-cy ( (4-Hiroshiru) Flow 0.10 part

An organic anti-reflection film having a thickness of 60 nm is provided on a silicon wafer which has been washed by a conventional method, and the above-mentioned resist solution is applied thereon using a spin coater. Pre-bake for seconds,
A resist film having a thickness of 0.52 μm was formed. Kr having an exposure wavelength of 248 nm was applied to the coating film after pre-baking through a chrome mask having a line and space pattern.
F excimer laser stepper [“NSR-
Using 2205 EX12B ", NA = 0.55], exposure was performed by changing the exposure stepwise by ordinary exposure. After the exposure, the wafer was heated on a hot plate at 105 ° C. for 60 seconds (post exposure).
Exposure bake). This was developed with a 2.38% aqueous solution of tetramethylammonium hydroxide to obtain a negative pattern.

The formed pattern was observed with an electron microscope, and the exposure (effective sensitivity) at which the cross section of the 0.20 μm line and space pattern became 1: 1 was determined.
It was ² mJ / cm ² . Further, the relative value of the film thickness of the resist pattern remaining after development was determined to be 98.7% based on the residual film ratio at an exposure amount of 25 mJ / cm ² , that is, the film thickness of the coating film after prebaking. Was.

Examples 2 to 5 and Comparative Examples 1 and 2 In the same manner as in Example 1 except that the resin shown in the column of "Second resin" in Table 1 was used instead of the resin R2, the amount shown in the same column was used. A resist solution was prepared by the above operation, and a resist film was formed on the wafer. Thereafter, exposure was carried out by changing the exposure conditions as shown in Table 1 in some cases, post-exposure bake and development were performed under the same conditions as in Example 1, and the effective sensitivity was determined by the same method. In some examples, the residual film ratio was determined in the same manner as in Example 1. The results are shown in Table 1 together with the composition variables and the results in Example 1. In Table 1, the example with "-" in the column of the remaining film ratio indicates that the remaining film ratio was not measured.

[0063]

[Table 1] 例 Example No. Second resin Exposure conditions Effective sensitivity Remaining film ratio ━━━━━━━ ━━━━━━━━━━━━━━━━━━ Example 1 R2 / 2.5 part normal exposure 32 mJ / cm ² 98.7% 〃2 R1 / 2.5 part normal exposure 32 mJ / cm ² −〃 3 R2 / 5.0 part Normal exposure 28 mJ / cm ² 99.2% 〃 4 R4 / 2.5 part Normal exposure 33 mJ / cm ² 98.2% ５ 5 R3 / 2.5 part Ring zone illumination 32 mJ / cm ² − ────────────────── Comparative Example 1 None Normal exposure 35 mJ / cm ² 97.0% 〃 2 None Ring illumination 37 mJ / cm ² − ━━━━━━━ ━━━━━━━━━━━━━━━━━━

The negative patterns obtained in Examples 1 to 5 had good profiles (pattern shapes) and vertical walls.

Reference Example Using 100.0 parts of resin RA as a solid content and 2.5 parts of resin R2 obtained in Synthesis Example 2 as a solid content, about 600 parts of propylene glycol monomethyl including the amount brought in from the resin solution were used. It was mixed and dissolved with ether acetate.
This solution was filtered through a fluororesin filter having a pore size of 0.1 μm to prepare a resin solution. An organic antireflection film having a thickness of 60 nm is provided on a silicon wafer washed by a conventional method, and the above resin solution is applied thereon using a spin coater, and then prebaked on a hot plate at 100 ° C. for 60 seconds, A resin film having a thickness of 0.52 μm was formed. For this resin film, TOF-SIMS (time-of-flight secondary ion
mass spectroscopy; time-of-flight secondary ion mass spectrometry)
M / Z = 127 corresponding to ₈ H ₁₅ O ⁻ and M / Z = 57 corresponding to C ₃ H ₅ O ⁻ derived from the resin RA were detected. From these relative values, it was confirmed that 96% of the surface was resin R2. It should be noted that in this analysis method, since the ionization is strong, M / is smaller than the predetermined molecular formula by two hydrogen atoms.
Z is mainly detected.

[0066]

According to the present invention, a resist composition containing a specific polymer as a resin component gives a high residual film ratio, is excellent in sensitivity and pattern profile, and has good coatability and resolution. This composition has a wavelength of 468 nm.
Line, 365 nm i-line, 248 nm KrF excimer light, 198 nm ArF excimer light, suitable for exposure using X-ray, electron beam, ion beam, etc. In lithography using such a light source, a fine resist pattern Can be formed with high precision.

Claims (10)

[Claims] (1) The following formula (I) (Wherein, R represents an optionally substituted saturated hydrocarbon residue having 6 to 20 carbon atoms, A represents a direct bond,> C = O or>
Represents SO ₂ , wherein R ¹ is hydrogen, alkyl having 1 to 4 carbons,
C1-C4 alkoxy, C2-C5 alkoxycarbonyl, C1-C5 acyl, C1-C1
5 represents a acyloxy, nitro, cyano, fluorine, chlorine or bromine) and a resin component containing a polymer having a substituted styrene unit represented by the formula (I), wherein the substituted styrene unit represented by the formula (I) is And 0.1 to 10% by weight of the total solids in the resist. (2) R has 6 to 12 carbon atoms which may be substituted;
The composition according to claim 1, which is a saturated hydrocarbon residue. (3) R is unsubstituted or alkoxy having 1 to 4 carbons, alkoxycarbonyl having 2 to 5 carbons, acyl having 1 to 5 carbons, acyloxy having 1 to 5 carbons,
2. A saturated hydrocarbon residue substituted with a group selected from phenyl, phenoxy, oxo, fluorine and chlorine.
Or the composition according to 2. 4. The composition according to claim ¹ , wherein R ¹ is hydrogen. 5. The composition according to claim 1, wherein the group corresponding to —OAR in the formula (I) is located at the p-position of a benzene ring hanging from the polymer main chain. 6. The composition according to claim 1, wherein the resin component further comprises a polymer having no unit represented by the formula (I). 7. The composition according to claim 6, wherein the polymer having no unit represented by the formula (I) is polyhydroxystyrene or a partially alkyl etherified product thereof. 8. The polymer having a substituted styrene unit represented by the formula (I) further comprises the following formula (II) The substituted styrene unit of the formula (I) and the hydroxystyrene unit of the formula (II) are present in the polymer in a molar ratio of 20:80 to 60:40. Or the composition according to 7. 9. The composition according to claim 1, further comprising an amine as a quencher. 10. The composition according to claim 1, further comprising a crosslinking agent for crosslinking the resin component by the action of an acid, and acting as a negative type.