JP3399141B2 - Chemically amplified positive resist material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to deep ultraviolet rays, electron beams, X-rays.
It has high sensitivity to high energy rays such as rays, and can be patterned by developing with an alkaline aqueous solution.
The present invention relates to a chemically amplified positive resist material suitable for fine processing technology.

[0002]

2. Description of the Related Art LSI to be Solved
Along with the higher integration and higher speed of photolithography, there is a demand for finer pattern rules, and with optical exposure, which is currently used as a general-purpose technology, we are approaching the essential resolution limit derived from the wavelength of the light source. is there. In photoexposure using a g-line (436 nm) or an i-line (365 nm) as a light source, the pattern rule of about 0.5 μm is the limit, and the integration degree of the LSI manufactured using this is 16 Mbit DR.
Up to the AM equivalent. However, the trial manufacture of LSI has already reached this stage, and the development of further miniaturization technology is urgently needed.

Due to such a background, deep-UV lithography is considered promising as a next-generation microfabrication technique. Deep-UV lithography can also process 0.3 to 0.4 μm, and when a resist material having low light absorption is used, a pattern shape having a side wall that is nearly vertical to the substrate becomes possible. In recent years, K, which has a high brightness as a light source for far-ultraviolet rays
A technique utilizing an rF excimer laser has been drawing attention, and a resist material having low light absorption and high sensitivity is required for its use as a mass production technique.

From these points, a chemically amplified resist material using an acid as a catalyst developed in recent years (Japanese Patent Publication No. 27660/1990).
And Japanese Patent Laid-Open No. 63-27829) are particularly promising resist materials for deep ultraviolet lithography which have high sensitivity, resolution and dry etching resistance and have excellent characteristics.

In this case, in the chemically amplified positive resist material, it is known that the acid generator used has a particularly large influence on the function as the chemically amplified resist material. Specific examples include the onium salts shown below.

[0006]

[Chemical 2]

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

However, in the case of a positive resist material, in the exposed area, the decomposition product produced by the absorption of the high energy rays by the acid generator is also oil-soluble, so that it dissolves in the alkaline aqueous solution in the exposed area. It is not possible to reduce the speed and increase the ratio of the alkali dissolution rate between the exposed area and the unexposed area (called dissolution contrast). Therefore, the chemically amplified resist using the above-mentioned onium salt is resolved during alkali development. The pattern shape is not rectangular because it has poor transparency, that is, the exposed part is not easily removed.
There was a defect that it became a trapezoidal forward taper.

In order to solve this problem, a tert-butoxycarbonyl group, which is an acid labile group, is introduced into p-hydroxyphenylsulfonium salt and decomposed by high-energy radiation to generate an acid, which has alkali solubility. A phenol derivative is produced to increase the dissolution contrast (Japanese Patent Laid-Open No. 64-26550).
64-35433 and JP-A-2-12153).

However, even if a sulfonium salt which produces such a phenol derivative is used, high resolution is not satisfied.

Further, the conventional chemically amplified positive resist material is exposed to PEB (Post Exposure B) when exposed to deep ultraviolet rays, electron beams and X-ray lithography.
The problem that the line pattern becomes a T-top shape when the pattern is formed, that is, the upper part of the pattern becomes thick when the standing time before ake) becomes long [PED (PostE
xposure Deley)], which is considered to be because the solubility of the resist surface is lowered, which is a major drawback in practical use. Therefore, it is difficult to control the dimensions in the lithography process, and there is a problem that the dimension controllability is impaired even when the substrate is processed using dry etching [Reference: W. Hinsberg, et a
l. J. Photopolym. Sci. Techn
ol. , 6 (4), 535-546 (1993). ，
T. Kumada, et al. J. Photopo
lym. Sci. Technol. , 6 (4), 571
-574 (1993). ]. There is no chemically amplified positive resist material that solves this problem and is satisfactory.

In the chemically amplified positive resist material, P
It is believed that basic compounds in air are largely involved in the cause of ED problems. The acid on the resist surface generated by exposure reacts with the basic compound in the air, deactivates,
The longer the standing time to PEB is, the more the amount of deactivated acid increases, and thus the acid labile group is less likely to be decomposed. Therefore, a poorly soluble layer is formed on the surface, and the pattern is T
-It becomes a top shape.

However, it is known that the addition of a basic compound can suppress the influence of the basic compound in the air, and thus it is also effective for PED (Japanese Patent Laid-Open No. 232706/1993). JP-A-5-24968
No. 3), the basic compound used here is not incorporated into the resist film due to volatilization or has poor compatibility with each component of the resist and its dispersion in the resist film is non-uniform, so that the effect is reproduced. It was found that there is a problem with the image quality and the resolution is reduced.

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

[0015]

MEANS TO SOLVE THE PROBLEMS As a result of various studies to achieve the above object, the present inventor found that the sulfoxide represented by the following general formula (2) was replaced with trimethylsilyl sulfonate (3) and di-tert-butoxy. A novel sulfonium salt having a di-tert-butoxyphenyl group as an acid labile group represented by the following general formula (1) obtained by reacting with phenyl grignard (4) is a high solution suitable for fine processing technology. It has been found that it is suitable as a component of a chemically amplified positive type resist material having an image property and can exert great power particularly in deep ultraviolet lithography.

[0016]

[Chemical 3] (In the formula, R ₁ represents a hydrogen atom, an alkyl group or an alkoxy group , X represents a chlorine atom or a bromine atom, Y represents trifluoromethanesulfonate or p-toluenesulfonate, and n is an integer of 0 to 2. , M is an integer of 1 to 3, and n + m =
It is 3. )

The resist material containing the sulfonium salt represented by the general formula (1) of the present invention has a large dissolution contrast due to the effect of the acid labile group of the sulfonium salt represented by the general formula (1). It is possible to provide a chemically amplified positive resist material having high resolution suitable for fine processing technology.

That is, the resist material containing the above-mentioned sulfonium salt of the present invention has a low alkali solubility of the sulfonium salt itself, but the acid and PEB (Post Expos) produced by decomposition by irradiation with high energy rays.
Due to the action of ure Bake), the tert-butoxy group is efficiently decomposed and, for example, a catechol moiety or a resorcinol moiety having a higher alkali solubility than the phenol derivative is generated, so that a larger dissolution contrast can be obtained. Therefore, the novel sulfonium salt of the present invention can exhibit excellent performance as an acid generator of a chemically amplified positive resist material, and can obtain a resist image having high resolution and a wide depth of focus.

The present invention will be described in more detail below. The chemically amplified positive resist material is represented by the following general formula (1).
It contains a novel sulfonium salt represented by.

[0020]

[Chemical 4]

Here, in the above formula (1), n is an integer of 0 to 2, m is an integer of 1 to 3, and a combination of numbers is n + m = 3. R ₁ is a hydrogen atom, an alkyl group or an ar
It is a Coxy group . As the alkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, s
ec-butyl group, tert-butyl group, hexyl group, cyclohexyl group and the like having 1 to 8 carbon atoms are preferable,
Among them, methyl group, ethyl group, isopropyl group, tert
-Butyl group is more preferably used. As the alkoxy group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group,
A tert-butoxy group, a hexyloxy group, a cyclohexyloxy group and the like having 1 to 8 carbon atoms are preferable, and among them, a methoxy group, an ethoxy group, an isopropoxy group, and a tert group.
A -butoxy group is more preferably used.

[0022]

Y represents trifluoromethane sulfonate or p-toluene sulfonate, and the novel sulfonium salt of the present invention is specifically represented by the following formula (1a) or (1
It is shown in b).

[0024]

[Chemical 5] (In the formula, R ₁ , n and m have the same meanings as described above.)

In this case, in particular, by using the sulfonium salt of the formula (1b) as a component of the resist material, the effect of the p-toluenesulfonate anion, that is, deactivation of the acid by the basic compound in the air on the resist surface is used. Since the influence of T can be made extremely small, formation of a surface-insoluble layer can be suppressed, PED stability is good, and T
-Problem with a poorly soluble surface layer that causes the top shape, ie PE
The problem of D can be solved and good sensitivity can be obtained.

Specific examples of the sulfonium salt of the above formula (1a) include tris (3,4-di-tert-butoxyphenyl) sulfonium trifluoromethanesulfonate and bis (trifluoromethanesulfonate) as 3,4 type substituents. 3,4-di-tert-butoxyphenyl) phenylsulfonium, bis (3,4-di-tert-butoxyphenyl) trifluoromethanesulfonate (p-
Methylphenyl) sulfonium, bis (3,4-di-tert-butoxyphenyl) trifluoromethanesulfonate (m-methylphenyl) sulfonium, bis (3,4-di-tert-butoxyphenyl) trifluoromethanesulfonate (o- Methylphenyl) sulfonium,
Bis (3,4-di-te) trifluoromethanesulfonate
rt-butoxyphenyl) (p-methoxyphenyl) sulfonium, trifluoromethanesulfonic acid bis (3,3)
4-di-tert-butoxyphenyl) (m-methoxyphenyl) sulfonium, bis (3,4-di-tert-butoxyphenyl) trifluoromethanesulfonate
(O-Methoxyphenyl) sulfonium, bis (3,4-di-tert-butoxyphenyl) trifluoromethanesulfonate (p-tert-butoxyphenyl) sulfonium, trifluoromethanesulfonic acid (3,4-di-tert-butoxyphenyl) ) Diphenylsulfonium, trifluoromethanesulfonic acid (3,4-di-te
rt-Butoxyphenyl) bis (p-methylphenyl)
Sulfonium, trifluoromethanesulfonic acid (3,4
-Di-tert-butoxyphenyl) bis (m-methylphenyl) sulfonium, trifluoromethanesulfonic acid (3,4-di-tert-butoxyphenyl) bis (o-methylphenyl) sulfonium, trifluoromethanesulfonic acid (3,4 -Di-tert-butoxyphenyl) bis (p-methoxyphenyl) sulfonium, trifluoromethanesulfonic acid (3,4-di-tert-
Butoxyphenyl) bis (m-methoxyphenyl) sulfonium, trifluoromethanesulfonic acid (3,4-di-tert-butoxyphenyl) bis (o-methoxyphenyl) sulfonium, trifluoromethanesulfonic acid (3,4-di-tert-) Butoxyphenyl) bis (p
Etc. -tert- butoxy phenyl) sulfonium beam, also 2,4-type substituents include trifluoromethanesulfonic acid (2,4-di -tert- butoxy phenyl) diphenyl sulfonium trifluoromethane sulfonic acid (2,4 Di-tert-butoxyphenyl) bis (p
-Methylphenyl) sulfonium, trifluoromethanesulfonic acid (2,4-di-tert-butoxyphenyl) bis (m-methylphenyl) sulfonium, trifluoromethanesulfonic acid (2,4-di-tert-butoxyphenyl) bis (o -Methylphenyl) sulfonium, trifluoromethanesulfonic acid (2,4-di-te
rt-Butoxyphenyl) bis (p-methoxyphenyl) sulfonium, trifluoromethanesulfonic acid (2,4-di-tert-butoxyphenyl) bis (m
-Methoxyphenyl) sulfonium, trifluoromethanesulfonic acid (2,4-di-tert-butoxyphenyl) bis (o-methoxyphenyl) sulfonium, trifluoromethanesulfonic acid (2,4-di-tert-butoxyphenyl) bis (p etc. -tert- butoxy phenyl) sulfonium beam and the like.

Specific examples of the sulfonium salt of the above formula (1b) include tris (3,4-di-tert-butoxyphenyl) sulfonium p-toluenesulfonate and p-toluenesulfonic acid as 3,4 type substituents. Screw (3,
4-di-tert-butoxyphenyl) phenylsulfonium, p-toluenesulfonate bis (3,4-di-t)
ert-butoxyphenyl) (p-methylphenyl) sulfonium, p-toluenesulfonate bis (3,4-di-tert-butoxyphenyl) (m-methylphenyl) sulfonium, p-toluenesulfonate bis (3,3)
4-di-tert-butoxyphenyl) (o-methylphenyl) sulfonium, bis (3,4-di-tert-butoxyphenyl) (p-methoxyphenyl) sulfonium, p-toluenesulfonate bis ( 3,4-di-tert-butoxyphenyl)
(M-Methoxyphenyl) sulfonium, p-toluenesulfonic acid bis (3,4-di-tert-butoxyphenyl) (o-methoxyphenyl) sulfonium, p-toluenesulfonic acid (3,4-di-tert-butoxyphenyl) ) (P-tert-Butoxyphenyl) sulfonium, p-toluenesulfonic acid (3,4-di-tert)
-Butoxyphenyl) diphenylsulfonium, p-toluenesulfonic acid (3,4-di-tert-butoxyphenyl) bis (p-methylphenyl) sulfonium, p
-Toluenesulfonic acid (3,4-di-tert-butoxyphenyl) bis (m-methylphenyl) sulfonium, p-toluenesulfonic acid (3,4-di-tert-)
Butoxyphenyl) bis (o-methylphenyl) sulfonium, p-toluenesulfonic acid (3,4-di-ter
t-butoxyphenyl) bis (p-methoxyphenyl)
Sulfonium, p-toluenesulfonic acid (3,4-di-
tert-butoxyphenyl) bis (m-methoxyphenyl) sulfonium, p-toluenesulfonic acid (3,4
-Di-tert-butoxyphenyl) bis (o-methoxyphenyl) sulfonium, p-toluenesulfonic acid (3,4-di-tert-butoxyphenyl) bis (p
Etc. -tert- butoxy phenyl) sulfonium beam, also 2,4 type as the substituent, p- toluenesulfonic acid (2,4-di -tert- butoxy phenyl) diphenyl sulfonium, p- toluenesulfonic acid (2, 4-di-tert-butoxyphenyl) bis (p-methylphenyl) sulfonium, p-toluenesulfonic acid (2,4
-Di-tert-butoxyphenyl) bis (m-methylphenyl) sulfonium, p-toluenesulfonic acid (2,4-di-tert-butoxyphenyl) bis (o
-Methylphenyl) sulfonium, p-toluenesulfonic acid (2,4-di-tert-butoxyphenyl) bis (p-methoxyphenyl) sulfonium, p-toluenesulfonic acid (2,4-di-tert-butoxyphenyl) bis (M-Methoxyphenyl) sulfonium, p-
Toluenesulfonic acid (2,4-di-tert-butoxyphenyl) bis (o-methoxyphenyl) sulfonium, p-toluenesulfonic acid (2,4-di-tert-)
Butoxyphenyl) etc. bis (p-tert-butoxy phenyl) sulfonium beam and the like.

The sulfonium salt of the above formula (1) can be synthesized by the following route. That is, when synthesizing a novel sulfonium salt having one di-tert-butoxyphenyl group, a halogenated dihydroxybenzene represented by the following formula (5) and a halogenated dihydroxybenzene obtained by condensation of an acid of isobutene (6) are obtained. -Tert-Butoxybenzene (7)
Is reacted with magnesium in THF to give di-tert-butoxyphenyl Grignard (4), the sulfoxide represented by the following general formula (2) is reacted with trimethylsilyl sulfonate (3) in an organic solvent, and the Grignard reagent is added to this solution. By reacting, a novel sulfonium salt represented by the following general formula (1c) can be synthesized.

[0029]

[Chemical 6] (In the formula, R ₁ represents a hydrogen atom, an alkyl group or an alkoxy group , X represents a chlorine atom or a bromine atom, and Y represents trifluoromethanesulfonate or p-toluenesulfonate.)

In this case, when the halogenated dihydroxybenzene (5) is reacted with isobutene (6),
Isobutene (6) is 1 to 20 mol, preferably 5 to 1 mol per 1 mol of halogenated dihydroxybenzene (5).
In addition in an amount of 0 mol, a strong acid such as trifluoromethanesulfonic acid is used as a catalyst in an amount of 0.01 to 0.3 mol, preferably 0.02 to 0.1 mol, in an organic solvent such as methylene chloride. It is desirable to react in the temperature range of 10 to -70 ° C. As the halogenated dihydroxybenzene (5), 4-chlorocatechol, 4-bromoresorcinol and the like are preferably used. Halogenated di-
When reacting tert-butoxybenzene (7) with magnesium, it is desirable to carry out in an organic solvent such as THF.

Next, in synthesizing the sulfonium salt (1c), trimethylsilyl sulfonate (3) is used in an amount of 1 to 5 mol, preferably 2 mol, based on 1 mol of the sulfoxide (2).
~ 3 mol, di-tert-butoxyphenyl Grignard (4) at a ratio of 1-5 mol, preferably 2-3 mol, and tert-butoxy group due to a trace amount of acidic impurities present in trimethylsilyl sulfonate (3). In order to prevent the cleavage of the compound, it is allowed to react in an organic solvent such as THF and methylene chloride in the presence of an organic base such as triethylamine and pyridine to obtain a novel sulfonium salt (1c) as a target compound. The reaction temperature is 0
It is desirable to react at -10 ° C for 0.5 to 3 hours.

Examples of the sulfoxide (2) include diphenyl sulfoxide and bis (4-tert-butoxyphenyl) sulfoxide (2a) represented by the following general formula (JP-A-7-21 ).
5930 ), bis (4-dimethylaminophenyl) sulfoxide (2b), and the like are preferably used.

[0033]

[Chemical 7]

When synthesizing a novel sulfonium salt having two di-tert-butoxyphenyl groups, bis (3,4-di-tert-butoxyphenyl) sulfoxide (2c) is used as the sulfoxide and trimethylsilyl is used. A novel sulfonium salt represented by the following general formula (1d) can be synthesized by reacting the sulfonate (3) with the Grignard reagent (8).

[0035]

[Chemical 8] (In the formula, R ₁ represents a hydrogen atom, an alkyl group or an alkoxy group , X represents a chlorine atom or a bromine atom, and Y represents trifluoromethanesulfonate or p-toluenesulfonate.)

As the Grignard reagent (8), phenyl Grignard, 4-tert-butoxyphenyl Grignard, 4-tert-dimethylaminophenyl Grignard,
It is preferable to use p-methylphenyl Grignard or the like. In addition, bis (3,4-di-tert-butoxyphenyl) sulfoxide (2c) is 3,4-di-tert.
-Butoxyphenyl Grignard (4a) is obtained by reacting with thionyl chloride in an organic solvent such as THF.

[0037]

[Chemical 9] (In the formula, X represents a chlorine atom or a bromine atom.)

Further, when synthesizing a novel sulfonium salt having three di-tert-butoxyphenyl groups, bis (3,4-di-tert-butoxyphenyl) sulfoxide (2c) is used as the sulfoxide, and trimethylsilyl is used. A novel sulfonium salt represented by the following general formula (1e) can be synthesized by reacting the sulfonate (3) with di-tert-butoxyphenyl Grignard (4).

[0039]

[Chemical 10] (In the formula, R ₁ represents a hydrogen atom, an alkyl group or an alkoxy group , X represents a chlorine atom or a bromine atom, and Y represents trifluoromethanesulfonate or p-toluenesulfonate.)

The novel sulfonium salt having two or three di-tert-butoxyphenyl groups is
It can be synthesized under the same reaction conditions as the novel sulfonium salt having one tert-butoxyphenyl group.

In the present invention, the reaction of the above-mentioned phenol derivative (5) with isobutene (6) is described in [Experimental Chemistry Course, Fourth Edition, Organic Synthesis 2, p. 200, The Chemical Society of Japan, Maruzen] and [J. L. Holcombe and T.M. Livin
house J. Org. Chem. , 111-11
5.51. (1986). ] Was referred to for the synthesis.

It should be noted that the t at the 2,2'-position, such as bis (2,4-di-tert-butoxyphenyl) sulfoxide.
When a sulfoxide having an ert-butoxy group is used as a raw material, the target compound cannot be obtained due to steric hindrance.

The sulfonium salt represented by the general formula (1) is contained in the chemically amplified positive resist material. In this case, the sulfonium salt is a three- component system (alkali-soluble resin / acid generator / dissolving agent). it is good suitable for use as acid generators of chemically amplified positive resist composition of the inhibitor). This resist material contains (A) an organic solvent of 150 to
700 parts (weight part, the same applies hereinafter), preferably 250-5
00 parts, 70 to 90 parts, preferably 75 to 85 parts of the (B) alkali-soluble resin, and 5 to 40 parts of the dissolution inhibitor having an acid labile group in the (C) three-component chemically amplified positive resist composition. Parts, preferably 10 to 25 parts, (D) 1 to 15 parts of the sulfonium salt represented by the general formula (1),
It is desirable to contain 2 to 8 parts, and if necessary, (E) another acid generator of 0.5 to 15 parts, preferably 2 parts.
A mixture of up to 8 parts is preferred.

That is, specific examples of the resist material of the present invention include the following. i. (A) Organic solvent, (B) Alkali-soluble resin, (C) Dissolution inhibitor having acid labile group, (D) Sulfonium salt represented by general formula (1), and (E) Acid generator A chemically amplified positive resist material characterized by: ii. (A) Organic solvent, (B) Alkali-soluble resin, (C) Dissolution inhibitor having acid labile group, (D) Sulfonium salt represented by general formula (1), (E) General formula (2) below. Onium salt represented by (R ₂ ) _n Y (2) (wherein, R ₂ represents the same or different unsubstituted or substituted aromatic group, M represents sulfonium or iodonium, and Y represents
Represents trifluoromethane sulfonate or p-toluene sulfonate. n represents 2 or 3. And a chemically amplified positive resist material. iii. (A) Organic solvent, (B) Alkali-soluble resin, (C) Dissolution inhibitor having acid labile group, (D) Chemical amplification positive product containing sulfonium salt represented by general formula (1) Type resist material .

Here, as the organic solvent of the component (A),
Cyclohexanone, ketones such as 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, Ethers such as diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, etc. Examples thereof include one kind or two or more kinds. At this time, 1-ethoxy-2-propanol, which has the highest solubility of the acid generator of the resist component, is preferably used.

Examples of the alkali-soluble resin as the component (B) include polyhydroxystyrene and its derivatives. Examples of the polyhydroxystyrene derivative include those obtained by partially replacing the hydrogen atom of the hydroxyl group of polyhydroxystyrene with an acid labile group, and a copolymer of hydroxystyrene. In the case of the former, examples of the acid-labile substituent include a tert-butyl group, a tert-butoxycarbonyl group, a tetrahydropyranyl group, a methoxymethyl group, a trimethylsilyl group, and a tert-butyldimethylsilyl group. Butyl group, tert
-Butoxycarbonyl group and tetrahydropyranyl group are preferably used. In the latter case, the copolymer of hydroxystyrene includes a copolymer of hydroxystyrene and styrene, a copolymer of hydroxystyrene and tert-butyl acrylate, a copolymer of hydroxystyrene and tert-butyl methacrylate, Examples thereof include a copolymer of hydroxystyrene and maleic anhydride, a copolymer of hydroxystyrene and di-tert-butyl maleate, and the like. The weight average molecular weight of this polyhydroxystyrene or its derivative is 5,000 to 100,000.
It is preferably 0.

The dissolution inhibitor of the component (C) has one or more groups capable of being decomposed by an acid in the molecule,
It may be a low molecular weight compound or polymer. Examples of low molecular weight compounds include bisphenol A derivatives and carbonic acid ester derivatives. Particularly, the hydroxyl group of bisphenol A is tert-butoxy group or tert-butoxy group.
Compounds substituted with a butoxycarbonyloxy group are preferred. Examples of polymeric dissolution inhibitors include p-tert.
Examples thereof include a copolymer of butoxystyrene and tert-butyl acrylate and a copolymer of p-tert-butoxystyrene and maleic anhydride. In this case, the weight average molecular weight is preferably 5,000 to 10,000.

Examples of the acid generator as the component (E) include onium salts, oxime sulfonic acid derivatives, 2,6-dinitrobenzyl sulfonic acid derivatives, diazonaphthoquinone sulfonic acid ester derivatives, 2,4-bistrichloromethyl-6-.
Aryl-1,3,5-triazine derivative, α, α'-
Examples thereof include bisarylsulfonyldiazomethane derivatives.

An onium salt represented by the following general formula (2) is preferably used as the acid generator. (R ₂ ) _n MY (2) (In the formula, R ₂ represents the same or different unsubstituted or substituted aromatic group, M represents sulfonium or iodonium, and Y
Represents p-toluene sulfonate or trifluoromethane sulfonate. n represents 2 or 3. )

Examples of the aromatic group include a phenyl group and a phenyl group substituted with an alkyl group or an alkoxy group as described in the above formula (1).

Specific examples of the onium salt include the following iodonium salts and sulfonium salts.

[0052]

[Chemical 11]

Further, in the above resist material of the present invention, P
Additives such as a nitrogen-containing compound for ED stability, a surfactant for improving coatability, and a light absorbing material for reducing diffuse reflection from the substrate can be added.

For example, the nitrogen-containing compound has a boiling point of 1
Examples thereof include amine compounds or amide compounds at 50 ° C. or higher. 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-aminobenzoic acid, p-aminobenzoic acid, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 2-quinolinecarboxylic acid, 2-amino-4- Nitrophenol,
Examples thereof include triazine compounds such as 2- (p-chlorophenyl) -4,6-trichloromethyl-S-triazine. Among these, especially pyrrolidone, N-methylpyrrolidone, o-aminobenzoic acid, m-aminobenzoic acid, p
-Aminobenzoic acid, 1,2-phenylenediamine, 1,
3-Phenylenediamine and 1,4-phenylenediamine are preferably used.

Further, examples of the surfactant include perfluoroalkyl polyoxyethylene ethanol, fluorinated alkyl ester, perfluoroalkyl amine 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 of the present invention, the method of using light, and the like can be carried out by employing a known lithography technique. Particularly, in the resist material of the present invention, 254-1 is used.
It is most suitable for fine patterning by far-ultraviolet light of 93 nm and electron beam.

[0058]

The chemically amplified positive resist composition containing the novel sulfonium salt of the present invention has a dissolution contrast between exposed and unexposed areas because the sulfonium salt has a di-tert-butoxyphenyl group. Therefore, the resist material containing a sulfonium salt represented by the general formula (1) of the present invention has a high resolution suitable for a microfabrication technique. It has a high sensitivity to high energy rays such as ultraviolet rays, electron beams, and X-rays, especially KrF excimer laser, and can be patterned by developing with an alkaline aqueous solution, and has excellent sensitivity, resolution, and plasma etching resistance.
Moreover, the heat resistance of the resist pattern is also excellent.

[0059]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Prior to the description of the examples and comparative examples, synthetic examples of the novel sulfonium salt of the present invention are shown as reference examples.

Reference Example 1 Bis (4-tert-butane ) trifluoromethanesulfonate
Toxoxyphenyl) (3,4-di-tert-butoxide
Synthesis of (phenyl ) 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 further 28.6 g (0.13 mol) of trimethylsilyl triflate was added to 1
The mixture was added dropwise while controlling so as not to exceed 0 ° C.
To this solution, 1,2-di-tert-butoxy-4-chlorobenzene 20.5 g (0.08 mol), metallic magnesium 1.9 g (0.08 mol) and THF 40 g.
The Grignard reagent prepared by a conventional method was added dropwise while controlling so as not to exceed 10 ° C. Further, the reaction temperature was set to 0 to 10 ° C. and the reaction was aged for 30 minutes. After adding 300 g of 20% ammonium chloride aqueous solution to the reaction solution to stop the reaction and perform liquid separation, chloroform 3 was added to the organic layer.
00g was added. The organic layer was washed twice with 200 g of water and the solvent was distilled off under reduced pressure to obtain an oily substance. This oil was subjected to column chromatography (silica gel: eluent, chloroform-methanol), yield 12.9 g.
(Yield 35%), purity 99% bis (4-tert-butoxyphenyl) trifluoromethanesulfonate (3,3)
4-di-tert-butoxyphenyl) sulfonium was isolated.

The resulting trifluoromethanesulfonate bis (4-tert-butoxyphenyl) (3,4-di-
The results of nuclear magnetic resonance spectrum (NMR), infrared spectrum (IR), and elemental analysis of tert-butoxyphenyl) sulfonium are shown below.

[0062]

[Chemical 12] (A) 1.24 singlet 9H (b) 1.40 singlet 9H (c) 1.43 singlet 18H (d) 7.03-7.04 doublet 1H (e) 7.17-7. 20 Doublet 4H (f) 7.55 to 7.53 Doublet 4H (g) 7.32 to 7.35 Multiplet 1H (h) 7.21 to 7.24 Doublet 1H IR: (cm ^-1 ) 2080, 1586, 1488, 1396, 1369,
1309, 1265, 1225, 1160, 1076
1031, 937, 894, 836, 638 Elemental analysis value: (%) C ₃₅ H ₄₇ O ₇ S ₂ F ₃ theoretical value C: 60.0 H: 6.8 actual measurement value C: 60.1 H: 6.7

Reference Example 2 Bis (4-tert-butane ) trifluoromethanesulfonate
Toxyphenyl) (2,4-di-tert-butoxide
Synthesis of ( enyl) sulfonium 9.0 g (0.026 mol) of bis (4-tert-butoxyphenyl) sulfoxide was dissolved in 52 g of THF and cooled in an ice water bath. Triethylamine 2.
6 g (0.026 mol) was added, and further 14.9 g (0.07 mol) of trimethylsilyl triflate was added at 10 ° C.
It dripped while controlling so that it might not exceed. A Grignard reagent prepared by a conventional method using 21.1 g (0.07 mol) of 1,3-di-tert-butoxy-4-bromobenzene, 1.7 g (0.07 mol) of metallic magnesium and 56 g of THF in this solution. Was added dropwise while controlling so as not to exceed 10 ° C. Further, the reaction temperature was set to 0 to 10 ° C. and the reaction was aged for 30 minutes. After adding 140 g of 20% ammonium chloride aqueous solution to the reaction solution to stop the reaction and perform liquid separation, chloroform 100 is added to the organic layer.
g was added. The organic layer was washed twice with 100 g of water and the solvent was distilled off under reduced pressure to obtain an oily substance. This oily substance was subjected to column chromatography (silica gel: eluent, chloroform-methanol), yield 14.4 g (yield 79%), 99% pure bis (4-tert-butoxyphenyl) trifluoromethanesulfonate (2,2). 4-
Di-tert-butoxyphenyl) sulfonium was isolated.

The resulting trifluoromethanesulfonate bis (4-tert-butoxyphenyl) (2,4-di-
The results of nuclear magnetic resonance spectrum (NMR), infrared spectrum (IR), and elemental analysis of tert-butoxyphenyl) sulfonium are shown below.

[0065]

[Chemical 13] (A) 1.31 singlet 9H (b) 1.42 singlet 9H (c) 1.43 singlet 18H (d, g, h) 7.03 to 7.04 multiplet 3H (e) 7.17 ~ 7.20 Doublet 4H (f) 7.55 to 7.53 Doublet 4H IR: (cm ^-1 ) 2981, 1585, 1486, 1396, 1371,
1309, 1265, 1225, 1157, 1074
1031, 999, 890, 887, 844, 638 Elemental analysis value: (%) C ₃₅ H ₄₇ O ₇ S ₂ F ₃ theoretical value C: 60.0 H: 6.8 actual measurement value C: 60.2 H: 6 .7

Reference Example 3 Trifluoromethanesulfonic acid tris (3,4-di-t)
Synthesis of ert-butoxyphenyl) sulfonium 58.9 g (0.12 mol) of bis (3,4-di-tert-butoxyphenyl) sulfoxide was added to THF120.
g, and cooled in an ice-water bath. To this, 12.1 g (0.12 mol) of triethylamine was added, and 68.3 g (0.31 mo) of trimethylsilyl triflate was further added.
1) was added dropwise while controlling so as not to exceed 10 ° C. To this solution, 11.6 g (0.24 mol) of 1,2-di-tert-butoxy-4-chlorobenzene,
Metallic magnesium 5.8 g (0.24 mol) and TH
1 of the Grignard reagent prepared by a conventional method using 100 g of F
The mixture was added dropwise while controlling so as not to exceed 0 ° C.
Further, the reaction temperature was set to 0 to 10 ° C. and the reaction was aged for 30 minutes. 20% ammonium chloride solution 700 in the reaction solution
After the reaction was stopped by adding g, and liquid separation was performed, 300 g of chloroform was added to the organic layer. The organic layer was washed twice with 300 g of water and the solvent was distilled off under reduced pressure to obtain an oily substance.
The oil was subjected to column chromatography (silica gel: eluent, chloroform-methanol), yield 1
3.1 g (yield 20%), tris (3,4-di-tert-butoxyphenyl) sulfonium trifluoromethanesulfonate having a purity of 99% was isolated.

The nuclear magnetic resonance spectrum (NMR), infrared spectrum (IR), and elemental analysis results of the obtained tris (3,4-di-tert-butoxyphenyl) sulfonium trifluoromethanesulfonate are shown below.

[0068]

[Chemical 14] (A) 1.22 singlet 27H (b) 1.40 singlet 27H (c) 7.01 to 7.02 doublet 3H (d) 7.26 to 7.29 doublet 3H (e) 7 .40 to 7.43 multiplet 3H IR: (cm ^-1 ) 2080, 1579, 1484, 1402, 1394,
1369, 1270, 1222, 1160, 1076
1029, 937, 916, 881, 840, 833
640,638 Elemental _{analysis: (%) C 43 H 63} O 9 S 2 F 3 theoretical value C: 61.1 H: 7.5 Found C: 61.0 H: 7.4

[Reference Examples 4 and 5] In Reference Examples 1 to 3 above
Diphenyl sulfoxide instead of sulfoxide
Reactions were performed in the same manner as in Reference Examples 1 to 3 except that
A ruphonium salt was obtained. Reference example 4 Trifluoromethanesulfonic acid (2,4-di-tert
-Butoxyphenyl) diphenylsulfonium Purity 9
8% yield 42%Reference example 5 Trifluoromethanesulfonic acid (3,4-di-tert
-Butoxyphenyl) diphenylsulfonium Purity 9
9% Yield 30%

Reference Examples 6 to 8 In the above Reference Examples 1 to 3, trimethylsilyl-p-toluenesulfonate (boiling point: 113 to 117 ° C.) obtained by a conventional method from p-toluenesulfonic acid and trimethylsilyl chloride instead of trimethylsilyltriflate was used. /0.5-0.6 mmH
except that g) is used, the reaction is carried out in the same manner as in Reference Examples 1 to 3,
The following sulfonium salt having a p-toluenesulfonic acid group as a counter anion was synthesized. Reference Example 6 Bis (4-tert-butoxyphenyl) p-toluenesulfonate (2,4-di-tert-butoxyphenyl) sulfonium Purity 97% Yield 55% Reference Example 7 p
-Bis (4-tert-butoxyphenyl) toluenesulfonate (3,4-di-tert-butoxyphenyl)
Sulfonium Purity 99% Yield 39% Reference Example 8 Tris (3,4-di-tert-p-toluenesulfonate)
-Butoxyphenyl) sulfonium Purity 99% Yield 28%

[Examples and Comparative Example I] The following formula (Poly)
m. 1) Terminate the partial hydrogen atom of the hydroxyl group
Polyhydroxystyrene protected with a t-butoxycarbonyl group, polyhydroxystyrene in which a hydrogen atom of a partial hydroxyl group represented by the following formula (Polym.2) is protected with a tert-butyl group, or the following formula (Polym.
3) Polyhydroxystyrene in which a hydrogen atom of a hydroxyl group is partially protected by a tetrahydropyranyl group, and an acid generator selected from onium salts represented by the following formulas (PAG.1) to (PAG.5). , The following formula (DRI.1)
A 2,2′-bis (4-tert-butoxycarbonyloxyphenyl) propane dissolution inhibitor represented by
Dissolved in ethoxy-2-propanol, Table 1 and Table 2
A resist solution having the composition shown in was prepared.

A resist solution was prepared by filtering each of these compositions through a 0.2 μm Teflon filter. This was spin-coated on a silicone wafer and coated to 0.8 μm. Then, the silicone wafer was baked on a hot plate at 100 ° C. for 120 seconds.

Then, exposure was performed using an excimer laser stepper (NSR 2005EX NA = 0.5, manufactured by Nikon Corporation), and baking was performed at 90 ° C. for 60 seconds to obtain 2.38%.
Development with an aqueous solution of tetramethylammonium hydroxide made it possible to obtain a positive pattern.

The obtained resist pattern was evaluated as follows. First, the sensitivity (Eth value) was obtained. Next, 0.
Optimum exposure amount (sensitivity: Eop) that resolves the top and bottom of 35 μm line and space 1: 1
The minimum line width of the separated lines and spaces in this exposure amount was defined as the resolution of the evaluation resist. The shape of the resolved resist pattern was observed using a scanning electron microscope. The evaluation results of Examples are shown in Table 1, and the evaluation results of Comparative Examples are shown in Table 2.

[0075]

[Chemical 15]

[0076]

[Chemical 16]

[0077]

[Table 1]

[0078]

[Table 2]

[Examples, Comparative Examples II] Acid generators represented by the following formulas (PAG.6 to 8) or the above formulas (PAG.4, 4)
A positive type pattern was obtained in the same manner as in the above-mentioned Example and Comparative Example I except that 5) was used, and the obtained resist pattern was evaluated as follows. A nitrogen-containing compound was added to Example 28 as an additive for PED stability.

First, the sensitivity (Eth value) was determined. next,
The optimal exposure dose (sensitivity: Eo) is the exposure dose that resolves the top and bottom of a 0.35 μm line and space 1: 1.
As p), the minimum line width of the separated lines and spaces in this exposure amount was taken as the resolution of the evaluation resist. The shape of the resolved resist pattern was observed using a scanning electron microscope. Regarding the PED stability of the resist, after the exposure with the optimum exposure amount, PEB is performed by changing the standing time, and the time when the change of the resist pattern shape is observed, for example, the line pattern becomes the T-top shape or the resolution becomes impossible. It was evaluated by the time. The longer this time is PE
D High in stability. Table 3 shows the evaluation results of the examples, and Table 4 shows the evaluation results of the comparative examples.

[0081]

[Chemical 17]

[0082]

[Table 3]

[0083]

[Table 4]

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Watanabe 28-1 Nishifukushima, Chugiki-mura, Nakakubiki-gun, Niigata Pref. 28-1 Nishi-Fukushima Shin-Etsu Chemical Co., Ltd. Synthetic Technology Research Laboratory (72) Inventor Keijun Tanaka 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Yoshio Kawai Chiyoda, Tokyo 1-6, Saiwaicho, Uchi-ku, Nippon Telegraph and Telephone Corporation (72) Inventor, Jiro Nakamura, 1-1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo, Japan (56) Reference: JP-A-6-287174 (JP, A) JP 4-219757 (JP, A) JP 4-215662 (JP, A) JP 4-248554 (JP, A) JP 7-333834 JP, A) (58) investigated the field (Int.Cl. ^7, DB name) G03F 7/00 - 7/42

Claims (8)

(57) [Claims] 1. A chemically amplified positive resist composition containing a novel sulfonium salt represented by the following general formula (1). [Chemical 1] (In the formula, R ₁ represents a hydrogen atom, an alkyl group or an alkoxy group, and Y represents trifluoromethanesulfonate or p-
Indicates toluene sulfonate. n is an integer of 0 to 2, m is an integer of 1 to 3, and n + m = 3. ) 2. A chemically amplified positive type resist material containing a novel sulfonium salt represented by the following general formula (1 ′). [Chemical 18] (In the formula, Y is trifluoromethanesulfonate or p-
Indicates toluene sulfonate. ) 3. The chemically amplified positive resist composition according to claim 1, wherein the chemically amplified positive resist composition is a three-component system. 4. The chemically amplified positive resist composition according to claim 1, wherein the chemically amplified positive resist composition is a two-component system. 5. (A) an organic solvent, (B) an alkali-soluble resin, (C) a dissolution inhibitor having an acid labile group, (D) a general formula (1) according to claim 1 or claim 2. A chemically amplified positive resist composition containing a sulfonium salt represented by the general formula (1 ′) and an (E) acid generator. 6. (A) an organic solvent, (B) an alkali-soluble resin, (C) a dissolution inhibitor having an acid labile group, (D) a general formula (1) according to claim 1 or claim 2. A sulfonium salt represented by the general formula (1 ′), (E) an onium salt represented by the following general formula (2) (R ₂ ) _n MY ... (2) (In the formula, R ₂ is the same or different and is unsubstituted or Represents a substituted aromatic group, M represents sulfonium or iodonium, and Y
Represents trifluoromethane sulfonate or p-toluene sulfonate. n represents 2 or 3. And a chemically amplified positive resist material. 7. (A) an organic solvent, (B) an alkali-soluble resin, (C) a dissolution inhibitor having an acid labile group, (D) a general formula (1) according to claim 1 or claim 2. A chemically amplified positive resist material containing a sulfonium salt represented by the general formula (1 ′). 8. A polyhydroxystyrene having a weight average molecular weight of 5,000 to 100,000, in which hydrogen atoms of some hydroxyl groups are substituted with acid labile groups, as the alkali-soluble resin as the component (B). The chemically amplified positive resist material as described in any one of 5 to 7.