JPH0425530A - Siloxane polymer and resist composition - Google Patents

Abstract

PURPOSE:To obtain a siloxane polymer difficulty soluble in an alkali by hydrolyzing a carboxylic acid (anhydride) group-containing alkoxysilane, condensing the saponificate and esterifying at least part of the carboxylic acid of the obtained polysiloxane. CONSTITUTION:A carboxylic acid (anhydride) group-containing alkoxysilane (e.g. 4-trimethoxysilyltetrahydrophthalic anhydride) is hydrolyzed in the presence of optionally a catalyst (e.g. aqueous hydrochloric acid solution) in a solvent (e.g. ethanol), and the saponificate is condensed to obtain a polysiloxane. At least part of the carboxylic acid groups of the obtained polysiloxane are esterified to obtain a siloxane polymer. This siloxane polymer is mixed with an acid generator to obtain a resist composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resist composition for high-energy radiation that reproduces a positive pattern with high precision and has high resistance to oxygen plasma.

[Conventional technology]

A positive-type 7-otoresist made of a novolac resin and a photosensitizer, naphthoquinone diazide, has been recently used in the field of lithography because it has characteristics such as high sensitivity, high resolution, and alkali solubility. Now, the two-layer resist [B,
J, Lin (B, J.

Lin), solid state technology (So
Lid 5tate Technol, ), Volume 24,
73 (1981)], a pattern with a high shape ratio was formed by oxygen plasma etching (0, RIB) using a fine pattern of a resist thin film formed on the lower resist as a mask.
) is obtained by anisotropic etching.

This 02RIB resistance has become extremely important for resist materials, and materials that form oxides due to O□RIB, generally materials containing silicon, are said to have excellent 0 and RIB resistance. has been done. However, the currently used 7 photoresist has a drawback of poor 0□RIB resistance because it does not contain a silicon component. To solve this problem, polysiloxane-based resist materials have been proposed, but this type of material generally has a low glass transition temperature, so it is easy to get dust during processing, it is difficult to control the film thickness, and it is difficult to control the film thickness during development. There were major problems with compatibility with the process, such as deterioration of developability due to deformation.

[Problem to be solved by the invention]

Therefore, the glass transition temperature is high, and 02RIB
Resist materials with excellent resistance and alkaline development are expected. Furthermore, materials for deep ultraviolet rays are required to have low absorption in the far ultraviolet region.

An object of the present invention is to provide a siloxane polymer and a resist composition that solve the above problems.

[Means to solve the problem]

To summarize the present invention, the first invention of the present invention relates to a siloxane polymer. It is characterized by being wholly or partially esterified.

The second invention of the present invention relates to a resist composition, and is characterized in that it contains the siloxane polymer of the first invention and an acid generator.

In order to solve the above-mentioned problems, the present invention first has a siloxane bond as a skeleton structure. It has high RIE resistance, uses polyfunctional alkoxide as a raw material, and has a ladder-shaped siloxane structure to achieve a high glass transition temperature.Also, when the ester is irradiated with high-energy rays, it changes to an alkali-soluble carboxyl group, making it alkali-soluble. This allows development.

The siloxane polymer of the present invention is generally synthesized by the following method. First, a specific alkoxysilane is dissolved in alcohol such as ethanol, and water and a catalyst such as hydrochloric acid are added to this. This catalyst may optionally be omitted.

This reaction proceeds at room temperature, but may be heated if necessary. After a predetermined period of time has elapsed, the reaction solution is poured into water, and the precipitated product is filtered out and then dried. If a higher polymer is desired, the product may be further reacted with an alkali catalyst in a suitable solvent. Alternatively, it is also effective to proceed with condensation by further heating in bulk.

All commonly used esterification reactions can be used to esterify the carboxylic acid of the obtained polysiloxane.

Namely, examples include reaction of a carboxylic acid with an alcohol, reaction of a carboxylic acid with an acid chloride and then a metal alcoholade such as sodium, and reaction of a carboxylic acid with a metal salt such as potassium with a halogenated hydrocarbon.

Furthermore, since the polysiloxane obtained by hydrolysis and condensation of the metal alkoxide of the present invention generally has a silanol group at the end, there is a possibility that this condensation may occur and the properties may change over time. To avoid this, the silanol group can be replaced by another non-reactive substituent using a silylating agent.

The polyfunctional metal alkoxide having a carboxylic acid group or carboxylic acid anhydride group used in the present invention is not particularly limited. It's silane.

Specifically, 4-trimethoxysilyltetrahydrophthalic anhydride, 4-triethoxysilyltetrahydrophthalic anhydride, 4-triisopropoxysilyltetrahydrophthalic anhydride, 4-trimethoxysilyltetrahydrophthalic acid, 4- Examples include triethoxysilyltetrahydrophthalic acid and 4-triisopropo-bovine silyltetrahydrophthalic acid.

The present invention also includes polysiloxanes obtained by copolymerizing a metal alkoxysilane having a carboxylic acid group or a carboxylic acid anhydride group with a general-purpose metal alkoxide or metal chloride. Although this kind of general-purpose metal alkoxide is not particularly limited, the following are exemplified. dimethoxydimethylsilane, jetoxydimethylsilane, dimethoxymethyl 3.3.3-)lifluoropropylsilane, di-engineered toxydivinylsilane,
Jetoxydiethylsilane, 3-aminopropyljethoxymethylsilane, 3-(2-7minoethylamino)
Propyldimethoxymethylsilane, dimethoxymethylphenylsilane, jetoxymethylphenylsilane, dimethoxydiphenylsilane, jetoxydiphenylsilane, tris-(2-methoxyethoxy)vinylsilane, methyltrimethoxysilane, ethyltrimethoxysilane,
3.3.3-Trifluoropropyltrimethoxysilane, methyltriethoxysilane, 3-(N-methylamino)propyltrimethoxysilane, methyltris-(2-
(aminoethoxy)silane, triacetoxyvinylsilane, triethoxyvinylsilane, ethyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-
(2-aminoethylamino)propyltrimethoxysilane, phenyltrimethoxysilane, 2-cyanoethyltriethoxysilane, allyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, propyltriethoxysilane, hexyltrimethoxysilane, 3 -aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, methyltripropoxysilane, phenyltriethoxysilane, 3-[N-allyl-N-(2-aminoethyl)]aminopropyltrimethoxysilane, 3- (Nallyl-N-glycidyl)aminopropyltrimethoxysilane, 3-(N,N-diglycidyl)minopropyltrimethoxysilane. Among these, phenyltriethoxysilane and methyltriethoxysilane are particularly preferred from the viewpoint of availability of raw materials, reactivity, properties of the obtained product, etc. In addition, examples of metal chlorides include n-butyltrichlorosilane, dimethyldichlorosilane, ethyltrichlorosilane,
Methyltrichlorosilane, phenyltrichlorosilane,
Examples include trichlorovinylsilane and diphenyldichlorosilane. The siloxane polymer of the present invention has a light transmittance of 90% or more at 248 nm with a thickness of 1 μm, and even when copolymerized with phenyltriethoxysilane, it has a transmittance of 70% or more, making it a promising resist for excimer lasers. be.

The hydrolysis/condensation catalyst used in the present invention is not particularly limited, and acid catalysts and alkali catalysts are used. Examples of such acid catalysts include hydrochloric acid, hydrofluoric acid, nitric acid, and sulfuric acid. Examples of the alkali catalyst include ammonia, caustic soda, and caustic potash.

The siloxane polymer of the first invention can be applied to various uses in combination with a suitable acid generator.

The second invention of the present invention is one of such combinations,
The present invention relates to a resist composition comprising a siloxane polymer and an acid generator. The siloxane polymer of the first invention is poorly soluble in alkaline aqueous solutions because all or part of the carboxylic acid is esterified, but the siloxane polymer is difficult to dissolve in alkaline aqueous solutions, but the acid generated from the acid generator when irradiated with high-energy rays such as electron beams. As a catalyst, the ester is easily hydrolyzed and converted to an alkali-soluble carboxylic acid. That is, the resist composition of the present invention exhibits positive resist characteristics because the siloxane polymer in the irradiated portion becomes a corresponding carboxylic acid when irradiated with high-energy rays, and the irradiated portion is removed by alkaline development.

In this resist composition, the acid generator also serves as an agent for preventing the siloxane polymer from dissolving in the alkaline solution. The amount of acid generator added is usually in the range of 0.5 to 20% by weight, and if it is less than 0.5%, the amount of acid generated is small. This makes it difficult to achieve high sensitivity. Moreover, if it exceeds 20%, the silicon content as a resist material decreases, and the oxygen plasma resistance decreases. Further, there is a problem that absorption at 248 nm becomes large. Generally, a preferable addition amount is about 5%.

The acid generator in the present invention is not particularly limited, but the following - ship stock ■, ■, ■: ArN="MXn-(1) Arzl"MXn-(II) Ar3S"MXn-(m) (formula Medium MXn is BF, PF6, AsF5 and SbF,
Onium salts represented by (one selected from the group of), halogenated methyl triazine, tetrabromobisphenol A1 nitrobenzyl ester, etc. can be used. Some acid generators have low sensitivity to ultraviolet light having a wavelength of 300 nm or more, but in that case it is also possible to add a spectral sensitizer such as phenothiazine.

Next, an example of a method for forming a pattern using the resist composition of the present invention will be described. First, a film of an organic polymer material is formed on a substrate such as silicon, and the resist composition of the present invention is applied thereon to form a two-layer structure. Next, after heat treatment and irradiation with high-energy rays, the heat treatment promotes hydrolysis of the ester to make the irradiated area soluble in an alkaline aqueous solution, and then the resist composition in the irradiated area is removed by alkaline development. Next, using the resist composition in the non-irradiated area as a mask, a pattern is formed by dry etching using oxygen gas to remove the underlying organic polymer film. The above-mentioned organic polymer material may be of any type as long as it can be etched by oxygen plasma, but after pattern formation, when dry etching the substrate using this as a mask, resistance is required, so Group-containing polymers are preferred.

〔Example〕

The present invention will be explained in more detail below with reference to synthesis examples and examples of products of the present invention, but the present invention is not limited to these aspects.

Examples of synthesis of siloxane polymers are shown below.

Synthesis example 1 4-trimethoxysilyltetrahydrophthalic anhydride 2
7.2 g (0.1 mol) was dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto while stirring. 144 at room temperature
After reacting for a period of time, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polysiloxane. The product was soluble in solvents such as tetrahydrofuran (THF), ethanol, ethylene glycol monoethyl ether (ethyl cellosolve), methyl isobutyl ketone (MIBK), and acetone.

Clear, uniform films were obtained from these solutions.

The weight average molecular weight was approximately 1000. C=0 near 1700 to 1750 cm-' in the infrared absorption spectrum
Absorption based on the stretching vibration of (carboxylic acid) was observed, confirming the introduction of carboxyl groups.

By reacting this with isobutyne using toluenesulfonic acid as a catalyst, a tert-butyl esterified siloxane polymer was obtained. With esterification, the absorption of carboxylic acid shifted to the higher wavenumber side. The light transmittance at 248 nm was 92% (1 μm thickness). It was confirmed that tert-butyl esterification was also achieved when a carboxylic acid group was converted into an acid chloride and then reacted with tert-butyl alcoholade.

Synthesis Example 2 The polysiloxane having a carboxylic acid group obtained in Synthesis Example 1 was converted into an acid chloride and reacted with ○-nitrobenzyl alcoholade to obtain an 0-nitrobenzyl esterified siloxane polymer. Esterification was confirmed by infrared absorption spectrum.

Synthesis Example 3 A benzyl esterified siloxane polymer was obtained by using the polysiloxane having a carboxylic acid group obtained in Synthesis Example 1 as an acid chloride and reacting it with benzyl alcoholade.

Esterification was confirmed by infrared absorption spectrum.

Synthesis Example 4 The polysiloxane having a carboxylic acid group obtained in Synthesis Example 1 was made into an acid chloride, and was reacted with α,α-dimethylbenzyl alcoholade to obtain an α,α-dimethylbenzyl esterified siloxane polymer. Ta. Esterification was confirmed by infrared absorption spectrum.

Synthesis Example 5 The polysiloxane having a carboxylic acid group obtained in Synthesis Example 1 was made into a potassium salt and reacted with 4,4'-dimethoxytrityl chloride to produce a 4,4'-dimethoxytrityl esterified siloxane polymer. Obtained. Esterification was confirmed by infrared absorption spectrum.

Synthesis Example 6 The polysiloxane having a carboxylic acid group obtained in Synthesis Example 1 was made into a potassium salt, and the potassium salt was reacted with 4-methoxytrityl chloride to obtain a 4-methoxytrityl esterified siloxane polymer. Esterification was confirmed by infrared absorption spectrum.

Synthesis Example 7 4-trimethoxysilyltetrahydrophthalic anhydride 1
3.6 g (0.05 mol) and phenyltriethoxysilane 12. Og (0.05 mol) was dissolved in ethanol and an aqueous hydrochloric acid solution was added thereto with stirring.

After reacting at room temperature for 144 hours, the reaction solution was poured into distilled water, and the generated precipitate was filtered out to obtain a white polymer. Product 1 tTHF, ethanol, ethyl cellosolve,
It was soluble in solvents such as MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions. The infrared spectrum of the product film has 1700-1750
Absorption based on the stretching vibration of C=0 (carboxylic acid) was observed near cm-', confirming the introduction of a carboxyl group. Synthesis example 1 of polysiloxane having this carboxylic acid group
Tert-butyl esterification was performed in the same manner as above.

Synthesis Example 8 4-trimethoxysilyltetrahydrophthalic anhydride 1
3.6 g (0.05 mol) and phenyltriethoxysilane 12. og (0.05 mol) was dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto with stirring. After reacting at room temperature for 144 hours, the reaction solution was poured into distilled water, and the generated precipitate was filtered out to obtain a white polymer. Furthermore, the reaction solution was transferred to a Petri dish and incubated at 90°C in a nitrogen atmosphere for 2 hours.
Heated at 120° C. for 48 hours.

As a result, the weight average molecular weight increased to 3000. The products are THF, ethanol, ethyl cellosolve, M
It was soluble in solvents such as IBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions. The infrared spectrum of the product film has 1700-1750c
Absorption based on the stretching vibration of C=0 (carboxylic acid) was observed near m-', confirming the introduction of a carboxyl group.

This polysiloxane having a carboxylic acid group was converted into a tert-butyl ester in the same manner as in Synthesis Example 1.

Synthesis Example 9 4-trimethoxysilyltetrahydrophthalic anhydride 8
．． 16 g (0.03 mol) and 16.8 g (0.07 mol) of phenyltriethoxysilane were dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto with stirring.

After reacting at room temperature for 144 hours, the solvent and the like were removed to isolate the product.

Next, the product was refluxed for 12 hours in a nitrogen stream using MIBK as a solvent and caustic potassium as a catalyst. The product was purified by reprecipitation and neutralization to obtain a white polymer. The weight average molecular weight was approximately 20,000. The product was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions. In the infrared spectrum of the product film, absorption based on the stretching vibration of C-0 (carboxylic acid) was observed near 1700 to 1750 cm, confirming the introduction of carboxyl groups. This polysiloxane having a carboxylic acid group was converted into a tert-butyl ester in the same manner as in Synthesis Example 1.

Synthesis Example 10 4-trimethoxysilyltetrahydrophthalic anhydride 1
3.6 g (0.05 mol) and phenyltriethoxysilane 12. Og (0.05 mol) was dissolved in ethanol and an aqueous hydrochloric acid solution was added thereto with stirring.

After reacting at room temperature for 144 hours, the reaction solution was poured into distilled water, and the generated precipitate was filtered out to obtain a white polymer. The product was dissolved in MIBK, a THF solution containing trimethylsilyldimethylamine was added thereto, and the mixture was reacted for 24 hours. The reaction solution was poured into n-hexane to obtain a silylated polysiloxane.

Raw Jllll;! It was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions.

The infrared spectrum of the product film has 1700-175
Absorption based on the stretching vibration of C=0 (carboxylic acid) was observed near 0 cm-', confirming the introduction of a carboxyl group.

This polysiloxane having a carboxylic acid group was converted into a tert-butyl ester in the same manner as in Synthesis Example 1.

Synthesis Example 11 35.6 g (0.1 mol) of 4-triisopropoxysilyltetrahydrophthalic anhydride was dissolved in isopropyl alcohol, and an aqueous hydrochloric acid solution was added thereto while stirring. After reacting at room temperature for 144 hours, the reaction solution was poured into distilled water, and the generated precipitate was filtered out to obtain a white polymer.

The products are THF, ethanol, ethyl cellosolve, MI
It was soluble in solvents such as BK and acetone. Clear, uniform films were obtained from these solutions. The infrared spectrum of the product film contains C in the vicinity of 1700-1750 cm-'.
Absorption based on stretching vibration of =0 (carboxylic acid) was observed, confirming the introduction of a carboxyl group. This polysiloxane having a carboxylic acid group was converted into a tert-butyl ester in the same manner as in Synthesis Example 1.

Synthesis Example 12 4-trimethoxysilyltetrahydrophthal [1 product 13
．． 6 g (0.05 mol), phenyltriethoxysilane 9.60 g (0.04 mol) and diphenyljethoxysilane 2.72 g (0.01 mol) were dissolved in ethanol, and aqueous hydrochloric acid solution was added to this while stirring. was added. After reacting at room temperature for 144 hours, the reaction solution was poured into distilled water, and the generated precipitate was filtered out to obtain a white polymer. The product was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions. The infrared spectrum of the product film ranges from 1700 to
Absorption based on the stretching vibration of C=0 (carboxylic acid) was observed near 1750 cm, confirming the introduction of carboxyl groups. This polysiloxane having a carboxylic acid group was converted into a tert-butyl ester in the same manner as in Synthesis Example 1.

Synthesis Example 13 4-trimethoxysilyltetrahydrophthalic anhydride 1
3.6 g (0.05 mol), 8.9 g (0.04 mol) of phenyltriethoxysilane, and 2.21 g (0.01 mol) of 3-aminobrobyltriethoxysilane were dissolved in ethanol and stirred. At the same time, an aqueous hydrochloric acid solution was added thereto. After reacting at room temperature for 144 hours, the reaction solution was poured into distilled water, and the generated precipitate was filtered out to obtain a white polymer. The formic acid compound was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions. 1700 in the infrared spectrum of the product film.
Absorption based on the stretching vibration of C=0 (carboxylic acid) was observed near ~1750 cm-', confirming the introduction of a carboxyl group. This polysiloxane having a carboxylic acid group was converted into a tert-butyl ester in the same manner as in Synthesis Example 1.

Synthesis Example 14 4-trimethoxysilyltetrahydrophthalic anhydride 1
3.6 g (0.05 mol) and phenyltriethoxysilane 12. Og (0.05 mol) was dissolved in ethanol and an aqueous hydrochloric acid solution was added thereto with stirring. Thereafter, aqueous ammonia was added to adjust the pH of the reaction solution to 10. After reacting at 60° C. for 144 hours, the reaction solution was poured into distilled water, and the generated precipitate was filtered out to obtain a white polymer. The product was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions. The infrared spectrum of the product film contains 1700-1
Absorption based on the stretching vibration of C=0 (carboxylic acid) was observed near 750 cm-', confirming the introduction of a carboxyl group. This polysiloxane having a carboxylic acid group was converted into a tert-butyl ester in the same manner as in Synthesis Example 1.

Examples will be described below.

Example 1 A resist composition in which 10% by weight of 2,6-sinitropendyl tosylate was added to the siloxane polymer obtained in Synthesis Examples 1 to 14 was coated on a silicon wafer to a thickness of about 0.3μ0 by a spin cord method. , prebaked at 80°C for 20 minutes. After pre-beta, high energy beams (electron beams, X-rays, far ultraviolet rays) were irradiated. After irradiation, heat treatment was performed on a hot plate at 110 °C for 5 minutes, followed by micropolymer) 240
1 (manufactured by Sibley) and water in a developer solution of 1/1 ratio, and the amount of irradiation is such that there is no remaining film on the irradiated area. was taken as the sensitivity.

Table 1 shows the sensitivity and resolution. The resolution was evaluated by forming a line & space pattern, and the resolution was 0.3 μm for each material.
The following pattern was formed.

Example 2 A resist composition prepared by adding 0.5% by weight of phenothiazine as a spectral sensitizer to the polymer to the resist composition of Example 1 was applied to a silicon wafer to a thickness of about 0.3 μm, and heated at 80°C. Prebaked for 20 minutes. After prebaking, ultraviolet rays were irradiated using a mask aligner (manufactured by Canon).

After irradiation, heat treatment was performed in the same manner as in Example 1, followed by development with the same developer, and the sensitivity was determined as the irradiation amount at which the remaining film in the irradiated area was 0.

Table 2 shows the sensitivity and resolution. Resolution was evaluated by forming line and space patterns, and each material was 0.5 μm.
A wide pattern was formed.

Example 3 AZ-1350 resist (manufactured by Hoechst) was coated on a silicon wafer to a thickness of 3 μm, and heated at 200° C. for 30 minutes to make it insolubilized. The resist composition used in Example 1 or Example 2 was applied to a thickness of about 0.3 μm on this AZ resist, and prebaked at 80° C. for 20 minutes. After pre-beta, high energy beam (electron beam in the case of Example 1,
Irradiate with X-rays, far ultraviolet rays, and in the case of Example 2 ultraviolet rays),
Heat treated in the same manner as in Example 1 or Example 2,
Subsequently, development was performed using a developer having the same composition to form a pattern. Thereafter, the AZ resist was etched using a parallel plate type sputter etching apparatus using oxygen gas as an etching gas and using the above resist pattern as a mask. RF
By etching for 15 minutes under the conditions of power 0.2 W/cm2.02 and gas pressure 20 mTorr, the AZ resist in the portions not covered by the resist pattern completely disappeared.

Furthermore, any of the resist compositions used in Example 1 had 0
．． A 3 μm line and space pattern can be formed with a thickness of about 3 μm, and when the composition of Example 2 is used, it is 0.5 μm thick.
A line and space pattern was formed.

Example 4 A resist composition was prepared by adding the following acid generator to the siloxane polymer obtained in Synthesis Example 1, and the resist properties were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Acid generator ■Triphenylsulfonium hexafluoroarsenate 2% by weight Generator ■Triphenylsulfonium fluoroarceneate) 2% by weight Acid generator ■Diphenyliodonium hexafluoroarceneate 2% by weight Generator■
Bis(1-butylphenyl)iodonium triflate 2% by weight acid generator■
2.4-bis(trichloromethyl)-6-phenyl-1,3,5 triazine 10% by weight acid generator■
Iron allene hexafluorophosphate complex acid generator ■)'J (2,3-dibromopropyl) isocyanurate acid generator ■ 4-Methoxybenzenediazonium triple olomethane sulfonate acid generator ■ 2.4.6-tris (trichloromethyl )
-1,3,5-) Reazine 5% by weight 5% by weight 5% by weight 5% by weight Acid generator O tetrabromobisphenol 10% by weight Acid generator 0 dibromomethyl) IJ azine 5% by weight [Effects of the invention] Above explanation As mentioned above, the siloxane polymer of the present invention has
It is made slightly alkali-soluble by esterifying the carboxylic acid of an alkali-soluble polysiloxane. In a resist composition containing an acid generator that generates acid when irradiated with high-energy rays, the ester is hydrolyzed and converted to the original carboxylic acid using the acid as a catalyst, resulting in a non-swellable positive resist that can be developed in an alkaline manner. Become. Furthermore, since it contains silicon, it has high resistance to oxygen plasma, and therefore can be used as an upper layer resist of a two-layer resist.

Since it can be used in a two-layer resist, it has the advantage that fine patterns of 0.5 μm or less can be formed with a high aspect ratio.

Patent applicant: Nippon Telegraph and Telephone Corporation

Claims (1)

[Scope of Claims] 1. A siloxane polymer characterized by esterifying all or part of the carboxylic acid of a polysiloxane obtained by hydrolysis and condensation of an alkoxysilane having a carboxylic acid group or a carboxylic acid anhydride group. . 2. A resist composition comprising the siloxane polymer according to claim 1 and an acid generator.