JPH107650A - New sulfonium salt and chemical amplification positive resist material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound suitable as a component of a chemical amplification positive resist material having high resolution and suitable for fine processing technology. SOLUTION: This new compound is a sulfonium salt expressed by the formula (R<1> is an alkyl, an alkoxy or a dialkylamino; OR<2> is an acidunstable group; Y is a 2-20C straight, branched or cyclic alkyl, an arylsulfonate, etc.; (n) is an integer of 0-2; (m) isaninteqer of 1-3; n+m is 3; (r) is an integer of 1-5; (p) is an integer of 0-5; (q) is an integer of 0-4; q+r is an integer of 1-5), having at least one acid-unstable group on the phenyl group in the molecule and having an alkyl or arylsulfonate group substituted with a straight, branched or cyclic electron-attracting group, e.g. 2,2,2-trifluoroethanesulfonic acid (4-tbutoxyphenyl) diphenylsulfonium salt. The compound forms a chemical amplification positive resist material together with an organic solvent, an alkali-soluble resin and an acid generating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel sulfonium salt suitable as a component of a chemically amplified positive resist material suitable for fine processing technology and a chemically amplified positive resist material containing the sulfonium salt.

[0002]

2. Description of the Related Art LSI
With the demand for finer pattern rules in accordance with higher integration and higher speed, far-ultraviolet lithography is regarded as promising as a next-generation fine processing technology. The deep ultraviolet lithography can process 0.3 to 0.4 μm, and when a resist material having low light absorption is used, a pattern having a side wall nearly perpendicular to the substrate can be formed. In recent years, high-intensity KrF
Attention has been paid to a technique using an excimer laser. In order to use this technique as a mass production technique, a resist material having low light absorption and high sensitivity is demanded.

[0003] From such a viewpoint, an acid-catalyzed chemically amplified positive resist material recently developed (Japanese Patent Publication No. 2-2)
No. 7660, JP-A-63-27829, etc.) have high sensitivity, high resolution, and high dry etching resistance and have excellent characteristics, and are particularly promising resist materials for deep ultraviolet lithography.

In this case, it is known that the compounded acid generator has a particularly large effect on the function of the chemically amplified positive resist material in the chemically amplified positive resist material. Representative examples of such an acid generator include the following onium salts.

[0005]

Embedded image

Since the onium salt itself is an oil-soluble compound, when it is blended as a resist component, it has the effect of reducing the solubility of the resist material in an aqueous alkali solution and suppressing the film loss during development.

[0007] However, in the case of a positive resist material, the decomposition products generated by the absorption of high energy rays by the acid generator are also oil-soluble. It is impossible to reduce the speed and increase the alkali dissolution rate ratio (dissolution contrast) between the exposed part and the unexposed part.

For this reason, a tert-butoxycarbonyl group, which is an acid labile group, is introduced into a p-hydroxyphenylsulfonium salt, and a phenol derivative having alkali solubility is formed by the action of an acid generated by decomposition upon irradiation with high energy rays. To increase the dissolution contrast (Japanese Patent Application Laid-Open Nos. 64-26550 and 64-35).
No. 433, JP-A-2-12153).

However, such a tert-butoxycarbonyloxyphenylsulfonium salt lacks thermal stability and does not satisfy high resolution, and the generated acid is a metal halide such as a metal anion or trifluoromethanesulfonic acid. Since it is a strong acid and the acid strength of the generated acid is strong, it is possible to efficiently decompose the acid labile group with a small amount of acid.
If the standing time until Exposure Bake becomes long, the line pattern becomes a T-top shape when the pattern is formed, and tends to be easily affected by the contamination of the basic compound from the air.

[0010] This is because the acid on the resist film surface generated by the exposure reacts with and deactivates the basic compound in the air, and the longer the standing time until PEB is, the more the amount of deactivated acid increases. It is thought that this occurs because the decomposition of the unstable group is less likely to occur. In order to solve this problem, it is known to add a basic compound to a resist material in order to reduce the influence of a basic compound in the air (Japanese Patent Application Laid-Open Nos. 5-232706 and 5-249683). etc)
However, according to the study of the present inventors, the basic compound used here is not taken into the resist film due to volatilization, has poor compatibility with each component of the resist material, and is not easily dispersed in the resist film. It was found that there was a problem in the reproducibility of the effect due to the uniformity, and that the resolution was reduced.

A strong acid such as trifluoromethanesulfonic acid generated during the photolysis reaction causes an undesired side reaction during the PEB process when the tert-butoxycarbonyloxyphenyl group, which is an acid labile group, is decomposed. It has also been reported that a side reaction product in which the phenyl group is tert-butylated at the o-position decreases alkali solubility (Proc. SPIE, 2195, 74-83.
(1994)).

Further, when a photoacid generator which generates a weak acid such as unsubstituted alkylsulfonic acid, which is a weaker acid than trifluoromethanesulfonic acid, is used, the exposure from PEB
Even if the leaving time is long, the pattern shape changes little, but the decomposition efficiency of the acid labile group is poor, so a large amount of acid is required, and the exposure time increases with the decrease in sensitivity, which is not suitable for device manufacturing . In addition, since it is a weak acid, there is a problem that decomposition of the acid labile group may be insufficient.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a novel sulfonium salt suitable as a component of a chemically amplified positive resist material having high resolution suitable for fine processing technology, and a chemically amplified positive resist material containing the sulfonium salt.

[0014]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, a novel sulfonium salt represented by the following general formula (1) was obtained by the method described below. In addition, by using the sulfonium salt of the formula (1) as a component of the chemically amplified positive resist material, the sulfonium salt has high resolution suitable for fine processing technology, and can exert a great power particularly in deep ultraviolet lithography. I found something.

[0015]

Embedded image (Where R ¹ is an alkyl group, an alkoxy group, or a dialkylamino group, which may be the same or different, OR ² is an acid labile group, Y is a straight-chain having 2 to 20 carbon atoms, A branched or cyclic alkyl or aryl sulfonate in which, in the case of an alkyl group, one or more hydrogen atoms bonded to the carbon atom from the β-position onward, and in the case of an aryl group, one or more hydrogen atoms of the benzene ring. Two or more are substituted with electron withdrawing groups such as fluorine and nitro groups.
n is an integer of 0 to 2, m is an integer of 1 to 3, and n + m is 3. r is an integer of 1 to 5, p is an integer of 0 to 5, q is an integer of 0 to 4, and q + r is an integer of 1 to 5. )

That is, when the sulfonium salt of the above formula (1) of the present invention is used as a component of a chemically amplified positive resist material, although the sulfonium salt itself has low alkali solubility, it is formed by decomposition by irradiation with high energy rays. Acid, moisture in resist material and PEB (Post E
xposure bake), the acid labile group is efficiently decomposed, and a carboxylic acid moiety is formed when the compound has a phenol moiety or a tertiary carboxylate moiety such as a tert-butoxycarbonylmethyloxy group having high alkali solubility. Therefore, a higher dissolution contrast can be obtained. In addition, an oxygen atom is introduced at the 3-position of the phenyl group of the sulfonium salt so that the resonance structure between the oxygen atom and the sulfur atom as seen in the 4-substituted product cannot be obtained. In the sulfonium salt into which is introduced, the light absorption around 250 nm can be suppressed to the same level as that of the unsubstituted compound, and as a result, the transmittance as a resist material can be increased.

Further, the acid generated by irradiation with high-energy radiation is not a strong acid such as conventional trifluoromethanesulfonic acid, is not a relatively weak alkylsulfonic acid, and is a substituted alkyl or arylsulfonic acid having almost intermediate acid strength. Therefore, the effects of side reactions such as when a strong acid is used and deactivation of the generated acid by a basic compound on the surface of the resist film can be reduced, and such as when a weak acid such as an alkylsulfonic acid is used. The decomposition of the acid labile group is not insufficient, and the sensitivity is better.

Therefore, the sulfonium salt of the above formula (1) can exhibit excellent performance as an acid generator of a chemically amplified positive resist material, and the resist material containing the sulfonium salt of the above formula (1) By the effect of the acid labile group of the sulfonium salt of the formula (1), a resist image having a large dissolution contrast, high resolution and a wide depth of focus can be obtained.

The present invention will be described in more detail below. First, the present invention is represented by the following general formula (1), wherein the phenyl group in the molecule has at least one acid labile group, And a novel sulfonium salt having a linear, branched or cyclic substituted alkyl or aryl sulfonate having 2 to 20 carbon atoms.

[0020]

Embedded image (Where R ¹ is an alkyl group, an alkoxy group, or a dialkylamino group, which may be the same or different, OR ² is an acid labile group, Y is a straight-chain having 2 to 20 carbon atoms, A branched or cyclic alkyl or aryl sulfonate in which, in the case of an alkyl group, one or more hydrogen atoms bonded to the carbon atom from the β-position onward, and in the case of an aryl group, one or more hydrogen atoms of the benzene ring. It is characterized in that two or more are substituted with an electron-withdrawing group such as fluorine or nitro group, n is an integer of 0 to 2, m is an integer of 1 to 3, and n + m is 3. r is An integer from 1 to 5,
p is an integer of 0-5, q is an integer of 0-4, and q + r is 1-5
Is an integer. )

In the above formula (1), R ¹ is an alkyl group, an alkoxy group or a dialkylamino group, and specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, Those having 1 to 8 carbon atoms such as a sec-butyl group, a tert-butyl group, a hexyl group and a cyclohexyl group are preferred, and among them, a methyl group, an ethyl group, an isopropyl group and a tert-butyl group are more preferably used. As the alkoxy group, those having 1 to 8 carbon atoms such as methoxy group, ethoxy group, propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, hexyloxy group and cyclohexyloxy group are preferable. Groups, ethoxy groups and isopropoxy groups are more preferably used. As the dialkylamino group, an amino group having an alkyl group having 1 to 4 carbon atoms such as a dimethylamino group, a diethylamino group, and a dipropylamino group is used. Among them, a dimethylamino group is preferable.

OR ² is an acid labile group. Here, as the acid labile group, for example, a tertiary alkoxy group such as tert-butoxy group, a carbonate group such as tert-butoxycarbonyloxy group, a tertiary carboxylic acid ester group such as tert-butoxycarbonylmethyloxy group, Trimethylsilyloxy group, triethylsilyloxy group, ter
Trialkylsilyloxy group such as t-butyldimethylsilyloxy group, tetrahydrofuranyloxy group, tetrahydropyranyloxy group, 2-methoxytetrahydropyranyloxy group, methoxymethyloxy group, 1-ethoxyethoxy group, 1-propoxyethoxy Group, 1-n-butoxyethoxy group, 1-iso-butoxyethoxy group,
1-sec-butoxyethoxy group, 1-tert-butoxyethoxy group, 1-amyloxyethoxy group, 1-ethoxy-1-methyl-ethoxy group, 1-propoxy-1-
Methyl-ethoxy group, 1-n-butoxy-1-methyl-
Ethoxy group, 1-iso-butoxy-1-methyl-ethoxy group, 1-sec-butoxy-1-methyl-ethoxy group, 1-tert-butoxy-1-methyl-ethoxy group, 1-amyloxy-1-methyl- Acetal or ketal groups such as ethoxy groups are exemplified.

Y is a linear, branched or cyclic substituted alkyl or aryl sulfonate having 2 to 20 carbon atoms. In this case, the substituted alkyl is the β of the alkyl group
One or two or more hydrogen atoms bonded to the carbon atom after the 1-position are substituted with an electron-withdrawing group, and substituted aryl means that one or more hydrogen atoms on the benzene ring have an electron-withdrawing group. Is replaced by Here, examples of the alkyl group include an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group, and examples of the aryl group include a phenyl group, a naphthyl group, and an alkyl-substituted phenyl group. Fluorine, nitro group,
A cyano group and the like, which is characterized by being bonded to a carbon atom at the β-position or later of the above-mentioned alkyl group or aryl group.

Specific examples of the substituted alkyl sulfonate include 2,2,2-trifluoroethyl sulfonate, 1H, 1H-heptafluoro-1-butyl sulfonate, 1H, 1H-perfluoro-1-heptyl sulfonate, and 1H. , 1H-perfluoro-1-dodecylsulfonate, 2-nitroethanesulfonate, 1-nitropropane-2-sulfonate, 2-nitropropane-
1-sulfonate; and substituted arylsulfonates such as pentafluorobenzenesulfonate,
-Fluorobenzenesulfonate, 2-, 3- or 4-nitrobenzenesulfonate, 2,4-dinitrobenzenesulfonate and the like are preferably used.

When a novel sulfonium salt having a substituted alkyl or aryl sulfonate which is a weaker acid than trifluoromethanesulfonic acid as the counter anion (Y ⁻ ) of the present invention is used as a resist material component, the effect of the weak acid anion, Since the influence of the deactivation of the acid by the basic compound in the air on the resist film surface can be made very small, the formation of a hardly soluble layer on the surface can be suppressed, and the PED stability is good. -It is possible to sufficiently solve the problem of the surface insoluble layer which is the cause of the top shape, that is, the problem of PED, and to obtain better sensitivity,
There is an advantage that the acid diffusion length in the resist after exposure can be set by selecting the anion species.

Specific examples of the sulfonium salt of the above formula (1) include the following. That is, as a sulfonium salt having an acid labile group at the 4-position, wherein the acid labile group is a tert-butoxy group, for example, 2,2,2-trifluoroethanesulfonic acid (4-tert-butoxy) Phenyl) diphenylsulfonium, pentafluorobenzenesulfonic acid (4-te
rt-butoxyphenyl) diphenylsulfonium, 1
H, 1H-heptafluoro-1-butanesulfonic acid (4
-Tert-butoxyphenyl) diphenylsulfonium, bis (4-tert-butoxyphenyl) phenylsulfonium 2,2,2-trifluoroethanesulfonate, tris (4-tert-butoxy) 2,2,2-trifluoroethanesulfonate Phenyl) sulfonium,
Tris pentafluorobenzenesulfonic acid (4-ter
t-butoxyphenyl) sulfonium, tris (4-tert-butoxyphenyl) sulfonium 4-fluorobenzenesulfonate, (4-tert-butoxyphenyl) bis (4-dimethylaminophenyl) 2,2,2-trifluoroethanesulfonate ) Sulfonium, (4-tert-butoxyphenyl) bis (4-dimethylaminophenyl) sulfonium pentafluorobenzenesulfonate and the like.

Examples of the sulfonium salt in which the acid labile group is a tert-butoxycarbonyloxy group include 2,2,2
-Trifluoroethanesulfonic acid (4-tert-butoxycarbonyloxyphenyl) diphenylsulfonium, pentafluorobenzenesulfonic acid (4-tert-
-Butoxycarbonyloxyphenyl) diphenylsulfonium, bis (4-tert-butoxycarbonyloxyphenyl) phenylsulfonium 2,2,2-trifluoroethanesulfonate, tris (4-tert- 2,2,2-trifluoroethanesulfonate) -Butoxycarbonyloxyphenyl) sulfonium, tris (4-tert-butoxycarbonyloxyphenyl) sulfonium pentafluorobenzenesulfonate, 2,2,2-
Trifluoroethanesulfonic acid (4-tert-butoxycarbonyloxyphenyl) bis (4-dimethylaminophenyl) sulfonium, 1H, 1H-heptafluoro-1-butanesulfonic acid (4-tert-butoxycarbonyloxyphenyl) bis (4 -Dimethylaminophenyl) sulfonium and the like.

Examples of the sulfonium salt in which the acid labile group is a tert-butoxycarbonylmethyloxy group include 2,2
2,2-trifluoroethanesulfonic acid (4-tert
-Butoxycarbonylmethyloxyphenyl) diphenylsulfonium, bis (4-tert-butoxycarbonylmethyloxyphenyl) phenylsulfonium pentafluorobenzenesulfonate, 1H, 1H-heptafluoro-1-butanesulfonic acid tris (4-tert-
Butoxycarbonylmethyloxyphenyl) sulfonium, 2,2,2-trifluoroethanesulfonic acid (4-
tert-butoxycarbonylmethyloxyphenyl)
Bis (4-dimethylaminophenyl) sulfonium, (4-tert-butoxycarbonylmethyloxyphenyl) bis (4-dimethylaminophenyl) sulfonium pentafluorobenzenesulfonate and the like can be mentioned.

As the sulfonium salt in which the acid labile group is an acetal or ketal group, those having a tetrahydropyranyl group include 2,2,2-trifluoroethanesulfonic acid (4- (2-tetrahydropyranyl)- Oxyphenyl) diphenylsulfonium, bis (4- (2-tetrahydropyranyl) -oxyphenyl) phenylsulfonium pentafluorobenzenesulfonate, 2,
Tris 2,2-trifluoroethanesulfonic acid (4-
(2-tetrahydropyranyl) -oxyphenyl) sulfonium, tris (4- (2-tetrahydropyranyl) -oxyphenyl) sulfonium pentafluorobenzenesulfonate, 2,2,2-trifluoroethanesulfonic acid (4- ( 2-tetrahydropyranyl) -oxyphenyl) bis (4-dimethylaminophenyl) sulfonium; and pentafluorobenzenesulfonic acid (4
-(2-tetrahydrofuranyl) -oxyphenyl) diphenylsulfonium, bis (4- (2-tetrahydrofuranyl) 2,2,2-trifluoroethanesulfonic acid
-Oxyphenyl) phenylsulfonium, 2,2,2
-Tris (4- (2-tetrahydrofuranyl) -oxyphenyl) sulfonium trifluoroethanesulfonate, tris (4- (2
-Tetrahydrofuranyl) -oxyphenyl) sulfonium, 2,2,2-trifluoroethanesulfonic acid (4
-(2-tetrahydrofuranyl) -oxyphenyl) bis (4-dimethylaminophenyl) sulfonium; and those having an ethoxyethyl group include (4-ethoxyethyloxyphenyl) diphenylsulfonium pentafluorobenzenesulfonate, 2,2,2-trifluoroethanesulfonic acid bis (4-ethoxyethyloxyphenyl) phenylsulfonium, 2,2,2-
Tris (4-ethoxyethyloxyphenyl) sulfonium trifluoroethanesulfonate, tris (4-ethoxyethyloxyphenyl) sulfonium 4-fluorobenzenesulfonate, 4-ethoxyethyloxy 2,2,2-trifluoroethanesulfonate Phenyl) bis (4-dimethylaminophenyl) sulfonium and the like.

Examples of the sulfonium salt in which the acid labile group is a trialkylsilyloxy group include 2,2,2-trifluoroethanesulfonic acid (4-trimethylsilyloxyphenyl) diphenylsulfonium and 4-fluorobenzenesulfonic acid bis (4 -Triethylsilyloxyphenyl) phenylsulfonium, tris (4-trimethylsilyloxyphenyl) sulfonium 2,2,2-trifluoroethanesulfonate, tris (4-triethylsilyloxyphenyl) pentafluorobenzenesulfonate
Sulfonium and the like.

As the sulfonium salt having an acid labile group at the 3-position, wherein the acid labile group is a tert-butoxy group, for example, 2,2,2-trifluoroethanesulfonic acid (3 -Tert-butoxyphenyl) diphenylsulfonium, (3-tert-butoxyphenyl) diphenylsulfonium pentafluorobenzenesulfonate, 1H, 1H-heptafluoro-1
-(3-tert-butoxyphenyl) diphenylsulfonium butanesulfonate, bis (3-tert-butoxyphenyl) phenylsulfonium 2,2,2-trifluoroethanesulfonate, tris 2,2,2-trifluoroethanesulfonate (3-tert-butoxyphenyl) sulfonium, tris (3-tert-butoxyphenyl) sulfonium, tris (3-tert-butoxyphenyl) sulfonate
tert-butoxyphenyl) sulfonium, 2,2
2-trifluoroethanesulfonic acid (3-tert-butoxyphenyl) bis (4-dimethylaminophenyl)
Sulfonium, pentafluorobenzenesulfonic acid (3
-Tert-butoxyphenyl) bis (4-dimethylaminophenyl) sulfonium and the like.

Examples of the sulfonium salt in which the acid labile group is a tert-butoxycarbonyloxy group include 2,2,2
-Trifluoroethanesulfonic acid (3-tert-butoxycarbonyloxyphenyl) diphenylsulfonium, pentafluorobenzenesulfonic acid (3-tert-
-Butoxycarbonyloxyphenyl) diphenylsulfonium, bis (3-tert-butoxycarbonyloxyphenyl) phenylsulfonium 2,2,2-trifluoroethanesulfonate, tris (3- (2,2,2-trifluoroethanesulfonate) tert-butoxycarbonyloxyphenyl) sulfonium, tris (3-tert-butoxycarbonyloxyphenyl) sulfonium pentafluorobenzenesulfonate, 2,2,2
-(3-tert-Butoxycarbonyloxyphenyl) bis (4-dimethylaminophenyl) sulfonium-trifluoroethanesulfonic acid (3-tert-butoxycarbonyloxyphenyl) bis (4-tert-butoxycarbonyloxyphenyl) sulfonium, 1H, 1H-heptafluoro-1-butanesulfonic acid Dimethylaminophenyl) sulfonium and the like.

Examples of the sulfonium salt in which the acid labile group is a tert-butoxycarbonylmethyloxy group include 2,2.
2,2-trifluoroethanesulfonic acid (3-tert
-Butoxycarbonylmethyloxyphenyl) diphenylsulfonium, bis (3-tert-butoxycarbonylmethyloxyphenyl) phenylsulfonium pentafluorobenzenesulfonate, 1H, 1H-heptafluoro-1-butanesulfonic acid tris (3-tert-
Butoxycarbonylmethyloxyphenyl) sulfonium, 2,2,2-trifluoroethanesulfonic acid (3-
tert-butoxycarbonylmethyloxyphenyl)
Bis (4-dimethylaminophenyl) sulfonium, (3-tert-butoxycarbonylmethyloxyphenyl) bis (4-dimethylaminophenyl) sulfonium pentafluorobenzenesulfonate and the like can be mentioned.

As the sulfonium salt in which the acid labile group is an acetal or ketal group, those having a tetrahydropyranyl group include 2,2,2-trifluoroethanesulfonic acid (3- (2-tetrahydropyranyl)- Oxyphenyl) diphenylsulfonium, bis (3- (2-tetrahydropyranyl) -oxyphenyl) phenylsulfonium pentafluorobenzenesulfonate, 2,
Tris 2,2-trifluoroethanesulfonic acid (3-
(2-tetrahydropyranyl) -oxyphenyl) sulfonium, tris (3- (2-tetrahydropyranyl) -oxyphenyl) sulfonium pentafluorobenzenesulfonate, 2,2,2-trifluoroethanesulfonic acid (3- ( 2-tetrahydropyranyl) -oxyphenyl) bis (4-dimethylaminophenyl) sulfonium; and pentafluorobenzenesulfonic acid (3-
(2-tetrahydrofuranyl) -oxyphenyl) diphenylsulfonium, bis (3- (2-tetrahydrofuranyl)-2,2,2-trifluoroethanesulfonic acid
Oxyphenyl) phenylsulfonium, 2,2,2-
Tris (3- (2-tetrahydrofuranyl) -oxyphenyl) sulfonium trifluoroethanesulfonate,
4-fluorobenzenesulfonic acid tris (3- (2-tetrahydrofuranyl) -oxyphenyl) sulfonium, 2,2,2-trifluoroethanesulfonic acid (3-
(2-tetrahydrofuranyl) -oxyphenyl) bis (4-dimethylaminophenyl) sulfonium, and those having an ethoxyethyl group include (3-ethoxyethyloxyphenyl) diphenylsulfonium pentafluorobenzenesulfonate, Bis (3-ethoxyethyloxyphenyl) phenylsulfonium 2,2-trifluoroethanesulfonate, tris (3-ethoxyethyloxyphenyl) sulfonium 2,2,2-trifluoroethanesulfonate, tris 4-fluorobenzenesulfonate (3-ethoxyethyloxyphenyl) sulfonium and (3-ethoxyethyloxyphenyl) bis (4-dimethylaminophenyl) sulfonium 2,2,2-trifluoroethanesulfonic acid.

Examples of the sulfonium salt in which the acid labile group is a trialkylsilyloxy group include 2,2,2-trifluoroethanesulfonic acid (3-trimethylsilyloxyphenyl) diphenylsulfonium and 4-fluorobenzenesulfonic acid bis (3 -Triethylsilyloxyphenyl) phenylsulfonium, tris (3-trimethylsilyloxyphenyl) sulfonium 2,2,2-trifluoroethanesulfonate, tris (3-triethylsilyloxyphenyl) pentafluorobenzenesulfonate
Sulfonium and the like.

In the above examples of the sulfonium salt, those having an acid labile group at the 4-position or 3-position of the phenyl group are exemplified. However, bis (3-tert-butoxyphenyl) sulfoxide (2d) described later And 4-tert-butoxyphenyl Grignard (4) as starting materials, a sulfonium salt having a 2-to-1 ratio of a 3-position substituent and a 4-position substituent can be synthesized, and bis (4-tert-butoxyphenyl) sulfoxide can be synthesized. By using (2b) and 3-tert-butoxyphenyl Grignard (4) as raw materials, a sulfonium salt having a 3-position substituent and a 4-position substituent in a ratio of 1: 2 can be synthesized.

The sulfonium salt of the above formula (1) of the present invention can be synthesized by the following route. First, a known method (J. Holcombe and T.A.
Livinghouse J. Org. Chem. , 1
11 to 115.51. (1986)) The 3 or 4-halogenated-tert-butoxybenzene prepared by the above method is reacted with metal magnesium in THF by a conventional method to obtain tert-butoxyphenyl Grignard represented by the following general formula (4). On the other hand, a diaryl sulfoxide represented by the following general formula (2) is reacted with a trialkylsilyl chloride or bromide represented by the following general formula (3) in an organic solvent, and further reacted with the Grignard reagent of the above (4). Thus, a sulfonium salt having a tert-butoxyphenyl group as an acid labile group represented by the following general formula (5) and having a chloride or bromide ion as an anion can be synthesized. Further, chloride or bromide ion of the sulfonium salt (5) is reacted with lead carbonate or an alkyl or aryl sulfonic acid represented by the general formula (6) in methanol to carry out anion exchange, thereby obtaining chloride or bromide ion. Can be removed as lead chloride or lead bromide, and a sulfonium salt (1a) having a substituted alkyl or aryl sulfonate as an anion and having a tert-butoxyphenyl group can be obtained. The formulation of this anion exchange is described in (F. Marshall J. A.
m. Chem. Soc. 342-351.81. (1
959)).

[0038]

Embedded image (Wherein, R ¹ , Y, p, q, and r are the same as above, and X is a bromine atom or a chlorine atom.
³ is a linear or branched alkyl group having 1 to 4 carbon atoms. )

Here, as the sulfoxide of the above formula (2), diphenyl sulfoxide, bis (3,4-di-tert-butoxyphenyl) represented by the following formula (2a)
Sulfoxide, bis (4-t) represented by the following formula (2b)
tert-butoxyphenyl) sulfoxide, of the following formula (2
bis (4-dimethylaminophenyl) sulfoxide represented by c), bis (3-te) represented by the following formula (2d)
It is desirable to use (rt-butoxyphenyl) sulfoxide and the like. These sulfoxides are disclosed in JP-A-7-215.
As described in JP-A-930, it can be prepared by reacting the corresponding Grignard reagent with thionyl chloride.

[0040]

Embedded image

As the trialkylsilyl chloride or bromide of the above formula (3), trimethylsilyl chloride,
It is desirable to use trimethylsilyl bromide, tert-butyldimethylsilyl chloride, tert-butyldimethylsilyl bromide, ethyldimethylsilyl chloride, ethyldimethylsilyl bromide, or the like.

In the present invention, a novel sulfonium salt having one or three tert-butoxyphenyl groups can be synthesized by using the above-mentioned sulfoxide as a raw material, and the bis () of the above formula (2b) or (2d) can be synthesized. By reacting tert-butoxyphenyl) sulfoxide with an aryl Grignard reagent represented by the following formula (7), for example, phenyl Grignard, 4-dimethylaminophenyl Grignard, etc., two tert-butoxy phenyl groups are obtained. , A sulfonium salt having a chloride ion or a bromide ion (5
By obtaining a) and further performing anion exchange in the same manner as described above, a novel sulfonium salt (1b) having a substituted alkyl or aryl sulfonate as an anion and having two tert-butoxyphenyl groups can be synthesized.

[0043]

Embedded image (In the above formula, R ¹ , R ³ , Y, X, p, and q are the same as above.)

As in the above reaction, an acid labile group and various functional substituents can be introduced by changing the combination of the diphenyl sulfoxide derivative and the aryl Grignard reagent. For example, in a sulfonium salt having three phenyl groups having an acid labile group, one having all the substituents at the 4-position of the phenyl group, one having all the substituents at the 3-position, and having two or three at the 4-position It can be synthesized in various combinations such as one having one, one in the fourth position and two in the third position.

When a sulfoxide having a tert-butoxy group at the 2-position or 2'-position, such as bis (2,4-di-tert-butoxyphenyl) sulfoxide, is used as the sulfoxide of the above formula (2), The desired compound cannot be obtained due to steric hindrance. The same applies to the case where a compound having a tetrahydropyranyloxy group at the 2-position and the 2'-position is used. However, a compound having a tert-butoxy group at the 2-position of (7), that is, a compound having only one disubstituted phenyl group can be synthesized.

In the prior art method of synthesizing a sulfonium salt or a sulfoxide compound by the reaction of phenol or anisole with thionyl chloride, the active site of phenol has two ortho and para positions. , May be different from the para-substituted product, and particularly the meta-substituted product cannot be obtained. Further, in this reaction, since hydrogen chloride gas is generated in the reaction system, tert
-It is difficult to synthesize a compound having an acid labile group such as butoxyphenyl as a raw material. On the other hand, in the method of the present invention, only the meta-substituted product is obtained quantitatively because the Grignard reagent is used, and only an inorganic salt such as magnesium chloride is generated instead of hydrogen chloride gas. The decomposition of the stable group does not proceed.

Further, in the prior art synthesis of a sulfonium salt which generates a strong acid such as sulfonium trifluoromethanesulfonate, a sulfoxide compound, a Grignard reagent, and a trialkylsilyl such as a trialkylsilyltrifluoromethanesulfonate can be used in the same manner as in the above reaction. Sulfonate is used, and an anion such as trifluoromethanesulfonate is introduced. However, even when this formulation is applied to the novel sulfonium salt of the present invention, introduction of a substituted alkyl or aryl sulfonate anion can be achieved, but when the acid strength is weak, quantitative introduction of the anion becomes difficult. On the other hand, in the above synthesis method in which chloride or bromide ions are removed as lead chloride or lead bromide, anion exchange can be performed almost quantitatively.

In the above synthesis method, the tert-butoxyphenyl Grignard reagent was used as a raw material for the sulfoxide and the sulfonium salt. However, a protecting group which is inactive to the Grignard reagent and can be removed by an acid, for example, tetrahydropyranyl The sulfonium salt of the above formula (1) can also be synthesized by using a Grignard reagent prepared by protecting the hydroxyl group of a halogenated phenol with a group, a tetrahydrofuranyl group, an ethoxyethyl group, or the like, and reacting with a metal magnesium.

In the above sulfonium salt synthesis reaction,
One mole of the sulfoxide of the above formula (2) is added with 1 mole of the trialkylsilyl chloride or bromide of the above formula (3).
It is preferable to mix the sulfoxide of the above formula (2) with the Grignard reagent of the above formula (4) or (8) in an amount of 1 to 5 moles, particularly 2 to 3 moles. It is preferably added in a molar ratio, particularly in a ratio of 2 to 3 mol. Furthermore, these reactions are caused by a trace amount of acidic impurities present in the trialkylsilyl halide of the above formula (3).
triethylamine to prevent elimination of the t-butoxy group,
It is desirable to carry out in an organic solvent such as THF and methylene chloride in the presence of an organic base such as pyridine. The reaction conditions for these reactions are not particularly limited, but the reaction temperature is preferably 0 to 10 ° C.

The anion exchange of the sulfonium salt having a chloride or bromide ion obtained under the above reaction conditions is not particularly limited, but is not particularly limited. The substituted alkyl or aryl sulfonic acid (6) is added at a ratio of 1.0 to 1.5 mol and lead carbonate at a ratio of 0.5 to 1.5 mol, and is added in an organic solvent such as methanol at a temperature of 0 to 50 ° C. The reaction is desirably performed for 30 minutes to 2 hours. In this case, if the proportion of the substituted alkyl or aryl sulfonic acid (6) and the reaction temperature are too high, the decomposition reaction of the tert-butoxyphenyl group, which is an acid labile group, may proceed.

Further, in the present invention, the tert-butoxy group of the sulfonium salt of the above formula (1a, 1b) is replaced by the general formula (6)
Is deprotected with a substituted alkyl or arylsulfonic acid represented by the formula, and a hydrogen atom of a phenolic hydroxyl group is tert-butoxycarbonyl group, tert-butoxycarbonylmethyl group, trialkylsilyl group, tetrahydropyranyl group, tetrahydrofuranyl group by a conventional method. , An ethoxyethyl group, a methoxymethyl group or the like, which is substituted by an acid labile group to have a desired acid labile group and a substituted alkyl or aryl sulfonate as an anion. Sulphonium salts can be obtained.

[0052]

Embedded image (In the above formula, R ¹ , R ² , Y, n, m, p, q, and r are the same as above.)

Here, the synthesis of substituted alkyl sulfonic acids is described in [R. K. Crossland, et. al. ,
J. Ame. Chem. Soc. , 93, 4217 (1
971). ].

The present invention further provides a chemically amplified positive resist material containing the sulfonium salt represented by the general formula (1). Here, this resist material is used as a chemically amplified positive resist material of a two-component system (organic solvent, alkali-soluble resin, acid generator) or a three-component system (organic solvent, alkali-soluble resin, acid generator, dissolution inhibitor). Although it can be prepared, it is particularly preferable to use it as a three-component chemically amplified positive resist material. The specific embodiment is as follows. [I] (A) an organic solvent, (B) an alkali-soluble resin,
A chemically amplified positive resist material comprising (C) a dissolution inhibitor having an acid labile group, (D) a sulfonium salt represented by the general formula (1), and (E) an acid generator. [II] (A) an organic solvent, (B) an alkali-soluble resin,
(C) a dissolution inhibitor having an acid labile group, (D) a sulfonium salt represented by the general formula (1), (F) an onium salt represented by the following general formula (8) (R ⁴ ) _a MY ′ (Wherein, R ⁴ is a same or different substituted or unsubstituted aromatic group, M is iodonium or sulfonium, Y ′ is a substituted or unsubstituted alkylsulfonate or arylsulfonate. A is 2 or 3.) A chemically amplified positive resist material comprising: [III] (A) organic solvent, (B) alkali-soluble resin, (C) dissolution inhibitor having acid labile group, (D) chemically amplified positive type containing sulfonium salt represented by general formula (1) Resist material. [IV] (A) an organic solvent, (B) an alkali-soluble resin,
(D) A chemically amplified positive resist material containing a sulfonium salt represented by the general formula (1). [V] (A) an organic solvent, (B) an alkali-soluble resin,
(D) a sulfonium salt represented by the general formula (1), (E)
A chemically amplified positive resist material containing an acid generator.

Here, as the organic solvent of the component (A),
Ketones such as cyclohexanone, methyl-2-n-amyl ketone, 3-methoxybutanol, 3-methyl-3-
Alcohols such as methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol Ethers such as dimethyl ether,
Propylene glycol monomethyl ether acetate,
Propylene glycol monoethyl ether acetate,
Ethyl lactate, ethyl pyruvate, butyl acetate, methyl-
Esters such as 3-methoxypropionate and ethyl-3-ethoxypropionate can be mentioned, and these can be used alone or in combination of two or more.

As the alkali-soluble resin of the component (B) as the base resin, polyhydroxystyrene or a derivative thereof may be mentioned. As the derivative of polyhydroxystyrene, one obtained by partially replacing the hydrogen atom of the hydroxyl group of polyhydroxystyrene with an acid-labile group is preferable, but a copolymer of hydroxystyrene can also be used. Examples of the acid-labile substituent include a tert-butyl group, a tert-butoxycarbonyl group, a substituent of a tert-butyl derivative such as a tert-butoxycarbonylmethyl group, a 1-ethoxyethyl group, a 1-propoxyethyl group, 1-n-butoxyethyl group, 1-iso-butoxyethyl group, 1-tert-butoxyethyl group, 1-
A linear or branched acetal group such as a tert-amyloxyethyl group, and a cyclic acetal group such as a tetrahydrofuranyl group, a tetrahydropyranyl group, and a 2-methoxy-tetrahydropyranyl group are preferred. Further, these acid labile groups may be used alone or in combination of a plurality of kinds. Further, the weight average molecular weight of the polyhydroxystyrene derivative is preferably 3,000 to 100,000. If it is less than 3,000, the film formability and resolution may be poor, and if it exceeds 100,000, the resolution may be poor. Examples of the copolymer of hydroxystyrene include a copolymer of hydroxystyrene and styrene, a copolymer of hydroxystyrene and tert-butyl acrylate, and a copolymer of hydroxystyrene and tert-methacrylate.
-Butyl, a copolymer of hydroxystyrene and maleic anhydride, and a copolymer of hydroxystyrene and di-tert-butyl maleate.

In the present invention, the sulfonium salt of the above formula (1) is blended as an acid generator as the component (D). If necessary, the sulfonium salt of the above formula (1) may be used as an acid labile group or an alkyl group. Alternatively, different kinds of arylsulfonates may be used in combination.
Further, if necessary, other acid generators can be blended as the component (E) in addition to the sulfonium salt of the above formula (1). Examples of the acid generator (E) include onium salts, oximesulfonic acid derivatives, 2,6-dinitrobenzylsulfonic acid derivatives, diazonaphthoquinonesulfonic acid ester derivatives, and 2,4-bistrichloromethyl-6-.
N-1, sulfonyloxyimide derivatives such as aryl-1,3,5-triazine derivatives, arylsulfonic acid ester derivatives, pyrogallolsulfonic acid ester derivatives, N-trifluoromethanesulfonyloxyphthalide and N-trifluoromethanesulfonyloxynaphthalide; ,
α'-bisarylsulfonyldiazomethane derivative,
α, α′-bisalkylsulfonyldiazomethane derivatives, etc., and particularly, the following general formula (8) (R ⁴ ) _a MY ′ (8) (where R ⁴ is the same or different, substituted or unsubstituted) An aromatic group, M is iodonium or sulfonium, Y 'is a substituted or unsubstituted alkylsulfonate or arylsulfonate, and a is 2 or 3.). These acid generators can be used alone or in combination of two or more.

Here, R ⁴ in the above formula (8) is
For example, aromatic groups such as a phenyl group and a phenyl group substituted with the same alkyl group or alkoxy group as R ¹ in the above formula (1) are preferably used. Specific examples of the onium salt of the above formula (8) include compounds having the following structures.

[0059]

Embedded image

Further, as the dissolution inhibitor of the component (C),
It has at least one group decomposed by an acid in the molecule, and may be any of low molecular weight compounds and polymers. Examples of low molecular weight compounds include bisphenol A derivatives and carbonate derivatives. In particular, the hydrogen atom of the hydroxyl group of bisphenol A is replaced with a tert-butoxy group, a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group or the like. Substituents of a -butyl derivative, 1-ethoxyethyl group, 1-propoxyethyl group, 1-n-butoxyethyl group, 1-iso-butoxyethyl group, 1-tert-butoxyethyl group, 1-te
Compounds substituted with a cyclic acetal group such as a linear or branched acetal group such as rt-amyloxyethyl group, tetrahydrofuranyl group, tetrahydropyranyl group, 2-methoxy-tetrahydropyranyl group, and 4,4- The hydrogen atom of the hydroxyl group of bis (4-hydroxyphenyl) -tert-butyl valerate is replaced with a tert-butoxy group,
Substituents of tert-butyl derivatives such as -butoxycarbonyl group and tert-butoxycarbonylmethyl group,
Ethoxyethyl group, 1-propoxyethyl group, 1-n-
Butoxyethyl group, 1-iso-butoxyethyl group, 1
Compounds substituted with a linear or branched acetal group such as -tert-butoxyethyl group and 1-tert-amyloxyethyl group, and a cyclic acetal group such as tetrahydrofuranyl group and tetrahydropyranyl group are preferable. The stable group may be a single group or a combination of plural groups.

Examples of the polymer dissolution inhibitor include p-
Examples include a copolymer of butoxystyrene and t-butyl acrylate and a copolymer of p-butoxystyrene and maleic anhydride. In this case, the weight average molecular weight is 5
00 to 10,000 is preferred.

The two-component chemically amplified resist composition of the present invention comprises 150 to 700 parts (parts by weight, hereinafter the same) of the organic solvent (A), particularly 250 to 500 parts, and the alkali-soluble resin (B). Is preferably blended in a proportion of 70 to 90 parts, especially 75 to 85 parts. In a three-component chemically amplified positive resist material, in addition to the above components,
(C) a dissolution inhibitor having an acid labile group of 5 to 40
Parts, especially 10 to 25 parts.

Further, the compounding amount of the sulfonium salt of the above formula (1) as the component (D) is 0.5 to 15 parts, particularly 2 to 15 parts.
If it is less than 0.5 part, the amount of acid generated at the time of exposure is small and sensitivity and resolution may be poor. If it exceeds 15 parts, the transmittance of the resist film is reduced and the resolution is poor. There are cases.

If another acid generator is added as a component (E) in addition to the sulfonium salt of the above formula (1), the acid generator of the component (E) may be added in an amount of 0.5 to 15 if necessary.
Parts, in particular, 2 to 8 parts.

The resist material includes additives such as a carboxylic acid derivative for PED stability, a nitrogen-containing compound, a surfactant for improving coating properties, and a light absorbing material for reducing irregular reflection from the substrate. Can be added.

Specific examples of the carboxylic acid derivative include 4-
Hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, 2-hydroxyphenylacetic acid, 3- (4-hydroxyphenyl) propionic acid, 3- (2-hydroxyphenyl) propionic acid, 2,5-dihydroxyphenylacetic acid, 3,4- Dihydroxyphenylacetic acid, 1,2-phenylene diacetate, 1,3-phenylene diacetate, 1,4-phenylene diacetate, 1,2-phenylenedioxy diacetate,
1,4-phenylenedipropanoic acid, benzoic acid, 4,4-
Bis (4-hydroxyphenyl) valeric acid, 4-tert
-Butoxyphenylacetic acid, 4- (4-hydroxyphenyl) butyric acid, 3,4-dihydroxymandelic acid, 4-hydroxymandelic acid and the like. The amount of the carboxylic acid derivative in the resist composition of the present invention is 0.1 to 15
Parts, particularly preferably 1 to 10 parts.

As the nitrogen-containing compound, an amine compound or an amide compound having a boiling point of 150 ° C. or higher is preferred. Specifically, aniline, N-methylaniline, N, N-dimethylaniline, o-toluidine, m- Toluidine, p
-Toluidine, 2,4-lutidine, quinoline, isoquinoline, formamide, N-methylformamide, N, N
-Dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methylpyrrolidone, imidazole, α-picoline, β-picoline, γ-picoline, o-aminobenzoic acid, m-amino Benzoic acid, p-aminobenzoic acid, 1,
2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 2-quinolinecarboxylic acid, 2-amino-4-nitrophenol, 2- (p-
Triazine compounds such as (chlorophenyl) -4,6-trichloromethyl-s-triazine. Among these, pyrrolidone, N-methylpyrrolidone, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine Is preferably used. The compounding amount of the nitrogen-containing compound in the resist material of the present invention is preferably 0.05 to 4 parts, particularly preferably 0.1 to 1 part.

Examples of the surfactant include perfluoroalkyl polyoxyethylene ethanol, fluorinated alkyl ester, perfluoroalkylamine oxide, perfluoroalkyl EO adduct and the like.

Further, examples of the light absorbing material include diaryl sulfoxide, diaryl sulfone, 9,10-dimethylanthracene, 9-fluorenone and the like.

The method of using the resist material and the method of using light can be carried out by using a known lithography technique. In particular, the resist material has a thickness of 254 to 193 nm.
It is most suitable for fine patterning by deep ultraviolet light and electron beam.

[0071]

The novel sulfonium salt of the above formula (1) according to the present invention has a large dissolution contrast between an exposed portion and an unexposed portion by introducing an acid labile group into the sulfonium salt as an acid generator. Further, at the time of exposure, a substituted alkyl or aryl sulfonic acid, which is a weak acid, is generated as compared with a conventional generated acid such as trifluoromethanesulfonic acid, so that a side reaction or a resist film surface may occur in the PEB process after exposure. Can reduce the effect of deactivation by neutralization of the generated acid by the basic compound,
Since it is not a weak acid like alkylsulfonic acid, it has relatively good sensitivity and is effective as a component of a chemically amplified positive resist material having high resolution suitable for fine processing technology. Also,
Introducing an oxygen atom at the 3-position of the phenyl group of the sulfonium salt,
In the case where a resonance structure with a sulfur atom cannot be obtained, that is, in a sulfonium salt having an acid labile group introduced at the 3-position, light absorption around 250 nm can be suppressed to the same level as that of an unsubstituted compound. Can be increased. Therefore, the resist material containing the sulfonium salt of the above formula (1) as an acid generator according to the present invention can be used as a chemically amplified positive resist material as far ultraviolet rays, electron beams,
It has high sensitivity to high energy rays such as X-rays, especially KrF excimer laser, can form patterns by developing with alkaline aqueous solution, and has excellent sensitivity, resolution, plasma etching resistance, and excellent heat resistance of resist patterns. ing.

[0072]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples. All parts in each example are parts by weight.

Synthesis Example 1 Tris 2,2,2-trifluoroethanesulfonic acid (4
Synthesis of -tert-butoxyphenyl) sulfonium 17.8 g (0.052 mol.) Of bis (4-tert-butoxyphenyl) sulfoxide was dissolved in 52 g of THF and cooled in an ice water bath. To this, 5.3 g (0.052 mol.) Of triethylamine was added, and 14.1 g (0.13 mol) of trimethylsilyl chloride was added dropwise while controlling so as not to exceed 10 ° C. Was done. 4
-Tert-butoxychlorobenzene 24.0 g (0.
13mol) and 3.2g (0.13m) of metallic magnesium
ol), and a Grignard reagent prepared by a conventional method using 40 g of THF was added dropwise while controlling so as not to exceed 10 ° C. Further, the reaction was ripened for 30 minutes at a reaction temperature of 0 to 10 ° C. After adding 300 g of a 20% aqueous ammonium chloride solution to the reaction solution to terminate the reaction and separate the solution,
500 g of chloroform was added to the organic layer. Organic layer with water 2
After washing twice with 00 g, the solvent was distilled off under reduced pressure to obtain an oil. This oil was subjected to column chromatography (silica gel: extract, chloroform-methanol) to give 9.3 g (35%) of purity 99.
% Of tris (4-tert-butoxyphenyl) sulfonium chloride was isolated.

9.3 g (0.018 mol) of this tris (4-tert-butoxyphenyl) sulfonium chloride was dissolved in 93 g of methanol, and 3.5 g of lead carbonate (0.01 g) was dissolved.
3 mol) and 3.6 g (0.022 mol) of 2,2,2-trifluoroethanesulfonic acid were added, and the mixture was heated to 50 ° C. After cooling, the precipitate was filtered and the solvent layer was distilled off under reduced pressure. 100 g of chloroform was added to the obtained residue, and 100 g of water was added.
After washing with water, the solvent layer was again distilled off under reduced pressure, and 97% pure 2,2,2-trifluoroethanesulfonic acid tris (4.
8.2 g of (-tert-butoxyphenyl) sulfonium was obtained in a yield of 25% (two steps).

The obtained 2,2,2-trifluoroethanesulfonic acid tris (4-tert-butoxyphenyl)
The results of nuclear magnetic resonance spectrum (NMR), infrared spectrum (IR) and elemental analysis of sulfonium are shown below.

[0076]

Embedded image (A) 1.42 singlet 27H (b) 7.15 to 7.19 doublet 6H (c) 7.58 to 7.62 doublet 6H (d) 3.53 to 3.64 quadruple 2H IR: (cm ^-1 ) 2975, 1585, 1481, 1371, 1315
1265,1251,1236,1234,1157,
1110, 1039, 896, 611. Elemental analysis: (%) C ₃₂ H ₄₁ O ₆ S ₂ F ₃ Theoretical value C: 59.8 H: 6.4 Analysis value C: 59.4 H: 6.3

Synthesis Example 2 2,2,2-trifluoroethanesulfonic acid (4-te
Synthesis of rt-butoxyphenyl) diphenylsulfonium Diphenylsulfoxide 20.2 g (0.10 mo
l. Was dissolved in 200 g of methylene chloride and cooled in an ice-water bath. 5.3 g of triethylamine (0.05 g)
2mol), and 32.6 of trimethylsilyl chloride was added.
g (0.30 mol) was added dropwise while controlling so as not to exceed 20 ° C., and the reaction was ripened for 15 minutes at a reaction temperature of 0 to 10 ° C. 4-tert-
55.4 g (0.30 mol) of butoxychlorobenzene
And 7.3 g (0.30 mol) of metallic magnesium, TH
10 g of Grignard reagent prepared by a conventional method using 90 g of F
The solution was added dropwise while controlling so as not to exceed ℃. Further, the reaction was ripened for 30 minutes at a reaction temperature of 0 to 10 ° C. A 20% aqueous ammonium chloride solution 500
After adding g, the reaction was stopped and liquid separation was performed, and then 1000 g of chloroform was added to the organic layer. After the organic layer was washed once with 200 g of water, the solvent was distilled off under reduced pressure to obtain an oil. When this oil was recrystallized, the yield was 26.6 g.
(4-tert-butoxyphenyl) diphenylsulfonium chloride with a purity of 98% (yield 72%) was isolated.

3.3 g (0.009 mol) of (4-tert-butoxyphenyl) diphenylsulfonium chloride was dissolved in 36 g of methanol, and 1.7 g of lead carbonate was obtained.
(0.0063 mol) and 1.6 g (0.010 mol) of 2,2,2-trifluoroethanesulfonic acid were added, and the mixture was heated to 40 ° C. After cooling, the precipitate was filtered and the solvent layer was distilled off under reduced pressure. After adding 100 g of chloroform to the obtained residue and washing with 100 g of water, the solvent layer was again distilled off under reduced pressure.
3.1 g of a 2,2,2-trifluoroethanesulfonic acid (4-tert-butoxyphenyl) diphenylsulfonium having a purity of 98% was obtained in a yield of 50% (two steps).

Nuclear magnetic resonance spectrum (NMR) of the obtained (4-tert-butoxyphenyl) diphenylsulfonium 2,2,2-trifluoroethanesulfonate,
The results of infrared spectrum (IR) and elemental analysis are shown below.

[0080]

Embedded image (A) 1.38 singlet 27H (b) 7.13 to 7.17 doublet 2H (c + c ') 7.60 to 7.66 multiplet 12H (d) 3.43 to 3.54 quadruple 2H IR: (cm ^-1 ) 2977, 1585, 1490, 1486, 1446,
1332, 1311, 1253, 1251, 1228,
1160, 1143, 1072, 1056, 752, 6
22. Elemental _{analysis: (%) C 24 H 25} O 4 S 2 F 3 theoretical value C: 57.8 H: 5.05 analysis C: 57.5 H: 5.00

Synthesis Example 3 A reaction was carried out in the same manner as in Synthesis Example 1 except that 4-fluorobenzenesulfonic acid was used instead of 2,2,2-trifluoroethanesulfonic acid in Synthesis Example 1. Tris (4-tert-butoxyphenyl) sulfonium-fluorobenzenesulfonate was obtained with a purity of 99% and a yield of 32%.

The results of nuclear magnetic resonance spectrum (NMR), infrared spectrum (IR) and elemental analysis of the obtained tris (4-tert-butoxyphenyl) sulfonium 4-fluorobenzenesulfonate are shown below.

[0083]

Embedded image (A) 1.39 singlet 27H (b) 7.11 to 7.14 doublet 6H (c) 7.59 to 7.62 doublet 6H (d) 6.85 to 6.91 triplet 2H (E) 7.86-7.91 triplet 2H IR: (cm ^-1 ) 2980,1583,1490,1369,1307,
1265, 1263, 1220, 1203, 1159,
1118, 1029, 894, 838, 682, 56
8. Elemental analysis: (%) C ₃₆ H ₄₃ O ₆ S ₂ F ₁ Theoretical value C: 66.0 H: 6.6 Analysis value C: 65.7 H: 6.3

[Synthesis Example 4] The reaction was carried out in the same manner as in Synthesis Example 2 except that pentafluorobenzenesulfonic acid was used instead of 2,2,2-trifluoroethanesulfonic acid. (4-tert-Butoxyphenyl) diphenylsulfonium benzenesulfonate was obtained with a purity of 98% and a yield of 36%.

The results of nuclear magnetic resonance spectrum (NMR), infrared spectrum (IR) and elemental analysis of the obtained (4-tert-butoxyphenyl) diphenylsulfonium pentafluorobenzenesulfonate are shown below.

[0086]

Embedded image (A) 1.35 singlet 9H (b) 7.11 to 7.14 doublet 2H (c + c ') 7.57 to 7.63 multiplet 12H IR: (cm ^-1 ) 2980,1648,1585, 1531, 1527,
1488, 1444, 1395, 1245, 1226,
1160, 1097, 1058, 981, 752, 68
4,659,632. Elemental analysis: (%) C ₂₈ H ₂₃ O ₄ S ₂ F ₅ Theoretical C: 57.7 H: 4.0 Analysis C: 57.5 H: 3.9

[Synthesis Example 5] The reaction was carried out in the same manner as in Synthesis Example 1 except that phenyl Grignard was used instead of 4-tert-butoxyphenyl Grinier in Synthesis Example 1, and the reaction was carried out. Bis (4-tert-butoxyphenyl) phenylsulfonium fluoroethanesulfonate was obtained with a purity of 98% and a yield of 34%.

Synthesis Example 6 A reaction was carried out in the same manner as in Synthesis Example 1 except that bis (4-dimethylaminophenyl) sulfoxide was used instead of sulfoxide in Synthesis Example 1, and the reaction was carried out. Ethanesulfonic acid (4
-Tert-butoxyphenyl) bis (4-dimethylaminophenyl) sulfonium has a purity of 98% and a yield of 28%
Was obtained.

Synthesis Example 7 The reaction was carried out in the same manner as in Synthesis Example 1 except that 4-dimethylaminophenyl Grignard was used instead of the Grignard reagent in Synthesis Example 1.
2,2-trifluoroethanesulfonic acid bis (4-te
(rt-butoxyphenyl) (4-dimethylaminophenyl) sulfonium was obtained with a purity of 98% and a yield of 32%.

[Synthesis Examples 8 to 11] Synthesis Examples 1, 5 to 7 except that pentafluorobenzenesulfonic acid was used instead of 2,2,2-trifluoroethanesulfonic acid used in Synthesis Examples 1, 5 to 7 As a result, sulfonium salts having pentafluorobenzenesulfonate as counter anions as described below were obtained. Synthesis Example 8: bis (4) pentafluorobenzenesulfonic acid
-Tert-butoxyphenyl) phenylsulfonium 98% pure, 35% yield Synthesis Example 9: pentafluorobenzenesulfonic acid (4-t
tert-Butoxyphenyl) bis (4-dimethylaminophenyl) sulfonium Purity 98%, Yield 32% Synthesis Example 10: Bis (4-tert-butoxyphenyl) pentafluorobenzenesulfonate (4-dimethylaminophenyl) sulfonium Purity 99 Synthesis Example 11: Tris (4-tert-butoxyphenyl) sulfonium pentafluorobenzenesulfonate Purity 99%, Yield 23%

Synthesis Example 12 4-tert- of Synthesis Example 1
3-tert-butoxyphenyl Grignard was used in place of butoxyphenyl Grignard, and bis (4-tert-
Bis (3-butoxyphenyl) sulfoxide
Reaction was carried out in the same manner as in Synthesis Example 1 except that tert-butoxyphenyl) sulfoxide was used.
Tris 2,2-trifluoroethanesulfonic acid (3-t
tert-butoxyphenyl) sulfonium has a purity of 98
% And a yield of 28%.

Synthesis Example 13 4-tert- of Synthesis Example 1
4-dimethylaminophenyl Grignard is used in place of butoxyphenyl Grignard, and bis (3-te) is used in place of bis (4-tert-butoxyphenyl) sulfoxide.
Reaction was carried out in the same manner as in Synthesis Example 1 except that (rt-butoxyphenyl) sulfoxide was used.
-Bis (3-tert-trifluoroethanesulfonic acid)
(Butoxyphenyl) 4-dimethylaminophenylsulfonium was obtained with a purity of 97% and a yield of 24%.

[Synthesis Example 14] 4-tert- of Synthesis Example 3
The reaction was carried out in the same manner as in Synthesis Example 3 except that phenyl Grignard was used instead of butoxyphenyl Grignard and bis (3-tert-butoxyphenyl) sulfoxide was used instead of bis (4-tert-butoxyphenyl) sulfoxide. At the same time, bis (3-tert-butoxyphenyl) phenylsulfonium 4-fluorobenzenesulfonate was obtained with a purity of 97% and a yield of 17%.

[Synthesis Examples 15 to 19] The novel sulfonium salt having a tert-butoxy group obtained in Synthesis Examples 1 to 14 was prepared by using the same sulfonic acid as a counter anion (eg, 2,2,2-trifluoroethanesulfonate). After deprotection in methanol or ethanol to obtain the corresponding hydroxyphenylsulfonium salt almost quantitatively, di-tert-butyl-dicarbonate or tert-butyl chloroacetate, dihydropyran, dihydrofuran, By using ethyl vinyl ether, a sulfonium salt having an acid labile group having a substituted alkyl or aryl sulfonate shown below as an anion was synthesized. Synthesis Example 15: Bis (3-tert-butoxycarbonylmethyloxyphenyl) phenylsulfonium 2,2,2-trifluoroethanesulfonate 99% purity, 14% yield Synthesis Example 16: pentafluorobenzenesulfonic acid (4-
tert-Butoxycarbonyloxyphenyl) diphenylsulfonium Purity 98%, Yield 20% Synthesis Example 17: Bis (4- (ethoxyethyl) oxyphenyl) dimethylaminophenylsulfonium 2,2,2-trifluoroethanesulfonate 98% Purity , Yield 2
0% Synthesis Example 18: Tris (4- (tetrahydrofuranyl) oxyphenyl) sulfonium pentafluorobenzenesulfonate 97% purity, 20% yield Synthesis Example 19: Tris (3- (2,2,2-trifluoroethanesulfonate) (Tetrahydropyranyl) oxyphenyl) sulfonium 97% pure, 17% yield

Examples 1 to 15 and Comparative Examples 1 to 5 As shown in Table 1, polyhydroxyl groups represented by the following formula (Polym. 1) in which hydrogen atoms of hydroxyl groups were partially protected by tert-butoxycarbonyl groups were used. Hydroxystyrene, the following formula (Poly
m. 2) Polyhydroxystyrene in which a hydrogen atom of a hydroxyl group is partially protected by a tetrahydrofuranyl group or polypolystyrene represented by the following formula (Polym. 3) in which a hydrogen atom of a hydroxyl group is partially protected by a 1-ethoxyethyl group Hydroxystyrene, and from the following formula (PAG.1), (PA
G. FIG. 5) an acid generator selected from onium salts represented by the following formula, and 2,2′-bis (4-tert-butoxycarbonyloxyphenyl) represented by the following formula (DRI.1).
The dissolution inhibitor for propane was dissolved in a solvent to prepare resist compositions having various compositions shown in Tables 3 and 4.

After the obtained resist composition was filtered through a 0.2 μm Teflon filter to prepare a resist solution, the resist solution was spin-coated on a silicone wafer and applied to 0.7 μm.

Next, this silicone wafer was put into 100
Baking was performed on a hot plate at 120 ° C. for 120 seconds. Furthermore, an excimer laser stepper (Nikon Corporation, NSR2005
(EXNA = 0.5), baked at 90 ° C. for 90 seconds, and developed with a 2.38% aqueous solution of tetramethylammonium hydroxide to obtain a positive pattern.

The obtained resist pattern was evaluated as follows. Table 1 shows the results. Resist pattern evaluation method: First, the sensitivity (Eth) was determined. Next, an exposure amount that resolves the top and bottom of a 0.30 μm line and space at a ratio of 1: 1 is defined as an optimum exposure amount (sensitivity: Eop) and a minimum line width of a separated line and space at this exposure amount. Is the resolution of the evaluation resist. The shape of the resolved resist pattern was observed using a scanning electron microscope.

Further, the PED stability of the resist is determined by performing PEB by changing the leaving time after exposure at the optimum exposure amount, and observing the change in the resist pattern shape, for example, the line pattern becomes T-top, The evaluation was made at the time when resolution could not be achieved. The longer this time, the better the PED stability. In Examples 14 and 15, a nitrogen-containing compound or a carboxylic acid derivative for PED stability was added as an additive. Table 1 shows the above results.

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[Table 1] EtOIPA: 1-ethoxy-2-propanol PGMEA: propylene glycol monomethyl ether acetate EL / BA: Mixed solution of ethyl lactate (85% by weight) and butyl acetate (15% by weight) NMP: N-methylpyrrolidone BHVA: 4,4 ' -Bis (4-hydroxyphenyl)
Valeric acid

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuya Takemura, 28-1 Nishifukushima, Nishi-Jukumura, Nakakubijo-gun, Niigata Prefecture Synthetic Research Laboratory, Shin-Etsu Chemical Co., Ltd. 28-1 Oishi Nishi-Fukushima Shin-Etsu Chemical Co., Ltd.Synthetic Technology Research Laboratories 3-19-2 Nishi Shinjuku, Shinjuku-ku Nippon Telegraph and Telephone Corporation

Claims (5)

[Claims] 1. A linear, branched or cyclic electron-withdrawing group-substituted alkyl or aryl sulfonate represented by the following general formula (1), having at least one acid labile group in a phenyl group in the molecule. A sulfonium salt having: Embedded image (Where R ¹ is an alkyl group, an alkoxy group, or a dialkylamino group, which may be the same or different, OR ² is an acid labile group, Y is a straight-chain having 2 to 20 carbon atoms, A branched or cyclic alkyl or aryl sulfonate in which, in the case of an alkyl group, one or more hydrogen atoms bonded to the carbon atom from the β-position onward, and in the case of an aryl group, one or more hydrogen atoms of the benzene ring. Two or more are substituted with electron withdrawing groups such as fluorine and nitro groups.
n is an integer of 0 to 2, m is an integer of 1 to 3, and n + m is 3. r is an integer of 1 to 5, p is an integer of 0 to 5, q is an integer of 0 to 4, and q + r is an integer of 1 to 5. ) 2. A chemically amplified positive resist material comprising the sulfonium salt represented by the general formula (1) according to claim 1. 3. (A) an organic solvent, (B) an alkali-soluble resin, (C) a dissolution inhibitor having an acid labile group, (D) a sulfonium salt represented by the general formula (1) according to claim 1,
(E) A chemically amplified positive resist material comprising an acid generator. 4. It comprises (A) an organic solvent, (B) an alkali-soluble resin, (D) a sulfonium salt represented by the general formula (1) according to claim 1, and (E) an acid generator. Chemically amplified positive resist material. 5. A polyhydroxystyrene having a weight average molecular weight of 3,000 to 100,000 in which a part of hydrogen atoms of a hydroxyl group is substituted by an acid labile group as the alkali-soluble resin of the component (B). Item 5. The resist material according to item 3 or 4.