JPH0612450B2 - Ionizing radiation sensitive positive resist - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a resist suitable for forming a fine pattern used in a lithographic process at the time of manufacturing a photomask used for the structure of high density integrated circuits such as LSI and VLSI, More specifically, it relates to a positive resist having high sensitivity and high resolution to ionizing radiation.

TECHNICAL BACKGROUND OF THE INVENTION AND PROBLEMS THEREOF In recent years, demands for higher integration and higher performance of semiconductor integrated circuits are increasing. Therefore, as the lithographic technique, in place of conventional photolithography using ultraviolet rays, ionizing radiation of shorter wavelength and higher energy, that is, lithography using electron beam, soft X-ray, ion beam, etc. Efforts to establish pattern processing technology continue.

On the other hand, in order to enable the ultrafine lithographic technique using such a special radiation source, the resist used must also have the characteristics corresponding to it. Generally, a resist material used for ultrafine lithography using high-energy ionizing radiation is required to have the following characteristics.

(B) High sensitivity to ionizing radiation.

(B) High resolution.

(C) Adhesion to the substrate is good.

(D) A homogeneous thin film can be formed.

(E) Excellent developability.

Conventionally, a large number of ionizing radiation sensitive resists used for the above purpose have been developed. These are a positive type in which a disintegration reaction is caused by irradiation of ionizing radiation to solubilize an irradiated part, and an ionizing radiation. It is classified as a negative type in which the cross-linking reaction is caused by the irradiation and the irradiated part becomes insoluble. Of these, the positive type is generally superior to the negative type in terms of resolution.

Typical positive resists known in the prior art include alkylmethacrylates such as polymethylmethacrylate and derivatives obtained by substituting these alkyl groups with various halogens, as well as olefins such as polybutene-1-sulfone. There are sulfone-based resists.

However, these conventional ionizing radiation sensitive positive type resists have the following drawbacks, and are not always satisfactory as resists used for ultrafine lithography.

For example, polymethylmethacrylate has a relatively high resolution, but its low sensitivity to ionizing radiation (for example, 1 × 10 ₋₄ clone / cm ² for electron beam).
There is a problem that it takes time to form a pattern (which requires the above irradiation amount). In addition, halogenated polyalkylmethacrylates are known to have relatively high sensitivity to ionizing radiation, but they have the problem of poor adhesion to the substrate and adhere to substrates such as silicon. The resist pattern thus formed is easily peeled off during development.
Furthermore, although olefin sulfone-based resists, such as polybutene-1-sulfone, have high sensitivity of one digit or more as compared with polymethylmethacrylate,
In order to obtain a patterning accuracy of a certain level or higher, the condition setting of the lithographic process (for example, developer composition, temperature,
(Processing time, etc.) and its control become difficult at all times.

DISCLOSURE OF THE INVENTION Objects of the Invention and Outline thereof The present invention has been made in view of the above-described problems of conventional resists, has high sensitivity and high resolution to ionizing radiation, and has good adhesion to a substrate. Another object of the present invention is to provide an ionizing radiation-sensitive positive resist excellent in developability.

The present inventors have studied to obtain a resist material that enables ultrafine lithography, and as a result, a polymer obtained by involving a Michael-type reaction such as a Michael addition reaction or a Michael-type polyaddition reaction, or these polymers It was found that a derivative obtained by chemically modifying a polymer is sensitive to ionizing radiation and has excellent properties as a positive resist material. The present invention has been made based on the above findings.

That is, the ionizing radiation-sensitive positive resist of the present invention is
(A) a polymer obtained by a Michael-type polyaddition reaction between a compound having an unsaturated bond and a compound having an active hydrogen group,
(B) Polymer obtained by Michael-type polyaddition reaction of a compound having an unsaturated bond and an active hydrogen group in the molecule, (c) Michael addition reaction of a compound having an unsaturated bond and an active hydrogen group A polymer obtained by the polymerization reaction of the monomer produced by or a copolymer obtained by the polymerization reaction of this monomer and another polymerizable monomer, (d),
It is characterized by comprising one or more polymers selected from the group consisting of (b) and (c) derivatives.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in more detail. In the following description, “%” representing the composition is based on weight unless otherwise specified.

The ionizing radiation-sensitive positive resist of the present invention is substantially composed of a polymer obtained by participating in a Michael type reaction, and causes a reverse Michael type decomposition reaction or a decomposition reaction upon irradiation with ionizing radiation.

For example, as a conventional electron beam sensitive positive resist,
A so-called depolymerization type resist in which a polymer is converted into a monomer by electron beam irradiation as typified by PMMA system, or a sulfone group portion is cleaved by electron beam irradiation as in poly (butene-1-sulfone) (PBS). A positive type consisting of a bond-breaking resist or a polymer such as poly (2-methylpentene-1-sulfone) which is easily decomposed by electron beam irradiation is mixed with an alkali-soluble novolak resin as a dissolution inhibitor. There is a resist. However, the present invention is essentially different from these conventional positive resists.

That is, the ionizing radiation-sensitive positive resist of the present invention is
It is substantially composed of a polymer obtained by participating in a Michael-type reaction, and is characterized by causing a reverse Michael-type decomposition reaction or a decomposition reaction upon irradiation with ionizing radiation.

The ionizing radiation that irradiates and solubilizes the resist of the present invention generally includes electron beams, soft X-rays, ion beams, etc., which have a shorter wavelength and higher energy than ultraviolet rays.

Further, in the present invention, the Michael type reaction substantially refers to Michael addition reaction and Michael type polyaddition reaction,
It means an addition reaction or a polyaddition reaction carried out between an electron-accepting type unsaturated bond site such as α, β-unsaturated carbonyl and an active hydrogen group. The synthesis of the polymer by the Michael type polyaddition reaction is described in, for example, "Polymer Chemistry", Vol. 26, No. 288 (1969), pages 271 to 279.

The polymers constituting the resist of the present invention can be classified into the following four types.

(I) A polymer obtained by a Michael-type polyaddition reaction between a compound having an unsaturated bond and a compound having an active hydrogen group; Examples of the polymer belonging to this type include, for example, α such as acryloyl group or methacryloyl group. , A β-unsaturated carbonyl group-containing compound and a Michael-type polyaddition reaction of an active hydrogen group such as a mercapto group (including hydrogen sulfide), a hydroxyl group or an amino group. α, β
-Preferred specific examples of the unsaturated carbonyl compound include:
For example, hydroquinone diacrylate having an acryloyl group at both ends of a molecular chain, p-xylene diacrylate, dibenzal acetone, divinyl sulfone, cyano-1,4-bis (hydroxymethyl) cyclohexane diacrylate, m-xylene bis. Acrylamide, methylenebisacrylamide, p-diacryloylbenzene, etc. may be mentioned. Further, the compound having an unsaturated bond in this type also includes a compound having the above-mentioned other triple bond. On the other hand, specific examples of the compound having an active hydrogen group include hydrogen sulfide or various dithiols such as ethanedithiol, propanedithiol, butanedithiol and hexamethylenedithiol, ethylene glycol, propylene glycol, 1,6-hexanediol, Hydroquinone, 1,4-benzenedimethanol, bisphenol A, diols such as diethylene glycol, ethylenediamine, hexamethylenediamine, N, N-dimethyl-1,6-hesamethylenediamine, trans-2,2-dimethylpiperazine, p
-Phenylenediamine, diaminodiphenyl ether,
Diamine such as anhydrous piperazine is preferably used.

Further, the polymer of the type (I) also includes a polymer obtained by a Michael type reaction between a monomer having an α, β-unsaturated carbonyl group and a polymer having an active hydrogen group in a side chain. Examples of such a polymer having an active hydrogen group include poly-p-vinylphenol, polyacrylamide, polyvinyl alcohol, poly-p-vinylaniline, poly-p-vinylthiophenol and poly-p-vinylaniline.
Examples include p-vinylbenzoylamide.

(II) Polymer Obtained by Michael Type Polyaddition Reaction of Compound Having Unsaturated Bond and Active Hydrogen Group in Molecule: Polymers belonging to this type include vinylbenzamide, maleimide, p-styrenesulfonamide, p Examples thereof include polymers obtained by binding styrenesulfonamidephenyl, acrylamide and the like by a Michael type polyaddition reaction. For example, the following polymers can be obtained from vinylbenzamide.

Further, a polymer having the following structure can be obtained by the Michael type polyaddition reaction of maleimide.

The unsaturated bond in this type also includes a triple bond.

(III) Polymer obtained by polymerization reaction of monomer formed by Michael addition reaction of compound having unsaturated bond and compound having active hydrogen group or this monomer and other polymerizable monomer Copolymers obtained by polymerization reaction with; As polymers belonging to this type, monofunctional α, β-unsaturated carbonyl compounds such as methyl acrylate, and β-aminoethanethiol and ethanolamine such as A monomer (for example, lactam thioether or thio-aminocaproic acid) obtained by Michael addition reaction with a monofunctional active hydrogen compound and intramolecular demethanol is obtained by a polymerization reaction such as ring-opening polymerization or polycondensation using an appropriate catalyst. There are polymers that can be used. For example, there are polyamide thioethers obtained from methyl acrylate and β-aminoethanethiol, and polyamide ethers obtained from methyl acrylate and ethanolamine.

Further, a polymer obtained by a polymerization reaction of a monomer produced by the Michael addition reaction and another polymerizable monomer can also be used. As a polymer belonging to this type,
There is a polymer obtained by a polymerization reaction such as polycondensation of a monomer obtained by a Michael addition reaction of an α, β-unsaturated carbonyl compound and an active hydrogen compound with another monomer using a suitable catalyst.

For example, monofunctional α, β such as methyl acrylate
-Monomers (methyl 3,3'-thiodipropionate) and diols obtained by Michael addition reaction of unsaturated carbonyl compounds with bifunctional active hydrogen compounds such as hydrogen sulfate (or ethanedithiol, propanedithiol, etc.) There are polyesters obtained as described below by polycondensation with (eg ethylene glycol, propylene glycol, bisphenol A etc.).

Further, this reaction can be more easily polymerized by using a chloride of 3,3'-thiodipropionic acid similarly synthesized by the Michael addition reaction. That is, 3,3'-thiodipropionic acid chloride and diol are each dissolved in a suitable solvent and the following polyester can be obtained by a usual interfacial polymerization method or solution polymerization method.

Further, here, the following polyamide can be obtained by using a diamine (hexamethylenediamine, piperazine, 3-amino-perhydroazepine, etc.) instead of the diol.

Further, this type of polymer can be similarly synthesized by using the following monomer species.

For example, by a Michael addition reaction between a difunctional α, β-unsaturated carbonyl compound such as dibenzalacetone and an active hydrogen compound (monofunctional) such as 3-mercaptopropionic acid, A monomer having carboxyl groups at both ends can be obtained.

This monomer is converted to an acid chloride with phosphorus pentachloride or thionyl chloride and reacted with a diol and a diamine by a normal interfacial polymerization method or a solution polymerization method under relatively mild conditions to obtain a polyester and a polyamide, respectively. Can be synthesized.

Further, both terminals of the monomer synthesized by Michael addition are not limited to the carboxyl group or its derivative. That is, it is sufficient if it has a functional group capable of polymerizing with another monomer (usually difunctional).

Furthermore, the compound having an unsaturated bond in this type also includes a compound having a triple bond. For example, by a Michael addition reaction of acetylene carboxylic acid and hexamethylenedithiol, the following monomer having a carboxyl group at both ends is obtained, Furthermore, this monomer and other polymerizable monomers (for example,
Polymers obtained by polymerization reaction with diamines and diols) can also be used in the present invention.

(IV) Derivatives of the above polymers (I), (II) to (III); The resist characteristics can be improved by chemically modifying the above polymers. For example, the thioether moiety can be sulfonated by treating the above-mentioned polyamide thioether with hydrogen peroxide or potassium permanganate at an appropriate concentration, whereby the sensitivity of the resist can be increased.

Further, the polymer can be trifluoroacetylated or propylated by treating the above polymer with trifluoroacetic acid or propyl bromide, thereby improving resist characteristics such as solubility of the resist.

The resist of the present invention may be constituted by using the above-mentioned polymers (I) to (IV) alone or as a mixed composition of these polymers. Further, it may be composed of a copolymer with another polymer having good compatibility with these polymers and good solvent solubility. Monomers that form such a copolymer include ε-caprolactam, α-piperidone, and α-piperidone. For example, such a copolymer includes the following polyamide copolymers.

Next, a method for actually performing lithography using the resist of the present invention will be described.

First, the resist of the present invention is dissolved in a single solvent or a mixed solvent such as formic acid, dimethyl sulfoxide, dimethylacetamide, dimethylformamide, toluene, xylene, methyl ethyl ketone, dioxane, etc., and has a viscosity suitable for coating of about 5 to 15%. Prepare the solution.

Then, this resist solution is uniformly applied to a semiconductor substrate or a mask substrate to be processed by a conventional method such as a spinner coating method, and a pre-baking treatment is performed to a thickness of 0.1.
A resist film having a thickness of about 2 μm is formed. The prebaking condition depends on the type of solvent used, but the temperature is 40 to 120 ° C,
A time of 20-40 minutes is suitable.

Then, a desired portion of the resist film is irradiated with an ionizing radiation such as an electron beam or a soft X-ray according to a conventional method to draw a pattern, and is further treated with a developing solution to selectively expose the resist film in the irradiated portion. A resist pattern is formed by dissolving and removing the resist pattern. As the developing solution, the same solvents as those used for preparing the resist solution described above and a mixed solvent of these with water and a lower alcohol are preferably used.

Further, a part of the resist of the present invention can be soaked in a gas atmosphere of CF ₄ , Ar or the like after pattern drawing by ionizing radiation and subjected to so-called dry development by low temperature gas plasma. This method is particularly suitable for developing fine patterns with high reproducibility and high accuracy without contaminating the sample surface with chemicals.

After developing the resist pattern, a post-baking treatment can be further performed if necessary. This post-baking treatment can be performed, for example, under conditions of a temperature of 100 to 180 ° C. and a time of 20 to 40 minutes.

Then, etching is performed to form an etching pattern on the exposed portion of the substrate. As etching, wet etching is suitable. After the etching process, the remaining resist pattern is removed and the lithographic process 1
The cycle is complete.

Examples of the Invention [Synthesis Example 1] 3.09 g (0.0132 mol) of dibenza-acetone, 1.98 g (0.0135 mol) of hexamethylenedithiol, 0.2 cm of piperidine
³ was added to dry benzene 0.2 cm ³ in dry benzene 15cm ^3, under a nitrogen atmosphere to 24 hours at stirring 30 ° C..
After the reaction, the reaction product was poured into methanol to collect the polymer. This polymer was dissolved in benzene and purified by repeating the procedure of reprecipitation with methanol, followed by vacuum drying, A polymer having the following structure was obtained. Benzene in this polymer 0.
The solution viscosity of the 1 g / 10 cm ² solution at 30 ° C. was 31 cm ³ / g.

[Synthesis Example 2] 7.38 g of p-xylene diacrylate (0.03
mol) and 0.50 g of diisopropylamine. Hydrogen sulfide gas was blown little by little to this to react, and the reaction product was poured into heptane to recover a polymer. After swelling this in methylene chloride overnight, reprecipitation in heptane,
After that, vacuum dry, A polymer having the following structure was obtained. Pyridine of this polymer
The solution viscosity of the 1 g / 10 cm ³ solution at 30 ° C. was 84 cm ³ / g.

[Synthesis Example 3] Ethylene glycol 0.28 g which is a bifunctional active hydrogen compound in the same amount as 1.0 g of hydroquinone diacrylate (HDA)
2 mol% of alkoxide with respect to HDA and 0.001 g of phenyl-β-naphthylamine as a vinyl polymerization inhibitor
Was dissolved in DMF 10 cm ³ , sealed in a test tube under high vacuum and reacted at a predetermined temperature for a certain period of time, then the product was recovered, washed with ether and dried in vacuum. A polymer having the following structure was obtained. Sulfuric acid of this polymer 0.1 / 1
The solution viscosity of the 0 cm ³ solution at 30 ° C. was 48 cm ³ / g.

[Synthesis Example 4] 9.370 g (0.108 m) of anhydrous piperazine in 60 cm ³ of anhydrous methanol
ol) was added, and divinyl sulfone 12.87 g (0.1
(08 mol) added to 20 cm ³ of anhydrous methanol was added dropwise with stirring at room temperature. 30 minutes after dropping, the polymer was separated and collected, washed with methanol, and dried in vacuum. A polymer having the following structure was obtained. 0.1g of sulfuric acid of this polymer
The solution viscosity of the / 10 cm ³ solution at 30 ° C. was 36 cm ³ / g.

[Synthesis Example 5] In 500 cm ^{3 of} tetrahydrofuran, 12 g (0.1 mol) of poly-para-vinylphenol having a molecular weight of about 80,000 and 8.6 g (0.1 mol) of methyl acrylate were added 2 mol% of sodium methoxide and stirred at 30 ° C. for 5 hours. did. After the reaction, the reaction solution was poured into a large amount of water to collect the polymer. The obtained polymer is dissolved in tetrahydrofuran, purified by repeating the operation of reprecipitation in water, dried in vacuum, A polymer having the following structure was obtained. THF of this polymer 0.1g /
The solution viscosity of the 10 cm ³ solution at 30 ° C. was 28 cm ³ / g.

[Synthesis Example 6] Poly-p-vinylaniline and ethyl acrylate were prepared in the same manner as in Synthesis Example 5. 0.1g of DMAc of this polymer was obtained.
/ 10 cm ³ solution The solution viscosity at 30 ° C. was 24 cm ³ / g.

[Synthesis Example 7] In the same manner as in Synthesis Example 5, poly-p-thiolstyrene and methyl acrylate were used. A polymer having the following structure was obtained. THF of this polymer 0.1g /
10 cm ³ solution The solution viscosity at 30 ° C. was 19 cm ³ / g.

[Synthesis Example 8] In the same manner as in Synthesis Example 5, poly-p-vinylbenzamide and methyl methacrylate were used. A polymer having the following structure was obtained.

The solution viscosity of the DMAc 0.1 / 10 cm ³ solution of this polymer at 30 ° C. was 32 cm ³ / g.

[Synthesis Example 9] 10 g of vinylbenzamide and potassium-te in 20 cm ^{3 of} DMF
rt Butoxide (0.015 g) and phenyl-β-naphthylamine (0.001 g) were added, and solution polymerization was carried out at 160 ° C for 19 hours. After the reaction, the reaction product was poured into methanol to collect the polymer, which was vacuum dried, A polymer having the following structure was obtained. 0.1g of sulfuric acid of this polymer
The solution viscosity of the / 10 cm ³ solution at 30 ° C. was 44 cm ³ / g.

[Synthesis Example 10] Maleimide 2.0 g, sodium-tert-butoxide 0.0
2g, N-phenyl-β-naphthylamine 0.002g 20cm
Add to the toluene of ³ and under nitrogen atmosphere at 60-120 ℃ 8
Reacted for hours. After the reaction, the reaction product was poured into methanol to collect the polymer, which was vacuum dried, A polymer having the following structure was obtained. DMF of this polymer 0.1g /
The solution viscosity of the 10 cm ³ solution at 30 ° C. was 20 cm ³ / g.

[Synthesis Example 11] 33.6 g of lactam thioether obtained from β-aminoethanethiol and acrylic acid and 0.3 g of metallic potassium were added to 170 cm ³ of xylene, heated to 130 ° C., and added with 0.3 g of N-acetylpyrrolidone, and added for 2 hours. After the reaction, the mixture was left to stand at room temperature with stirring. After the reaction, the precipitated polymer was collected, dissolved in formic acid, and reprecipitated with water to repeat the purification, followed by drying to obtain the following polyamide thioether.

0.1 g / c of the obtained polyamide thioether in concentrated sulfuric acid
The solution viscosity of the m ³ solution at 30 ° C. was 45 cm / g.

[Synthesis Example 12] 23.0 g of lactam thioether, 1 cm ^{3 of} water and 5 drops of phosphoric acid were added to a polymerization tube, and the mixture was allowed to react at 185 ° C for 5 hours in an oil solution. After the reaction, the obtained polymer was recovered, dissolved in formic acid, and reprecipitated with water to repeat purification, and dried to obtain polyamide thioether.

0.1 g / cm ^{3 of the} obtained polyamide thioether in concentrated sulfuric acid
The solution viscosity at 30 ° C. of the solution was 43 cm ³ / g.

[Synthesis Example 13] 16.3 g of methyl 4-thio-ε-aminocaproate and 02 g of lithium methoxide were added to 100 cm ³ of dimethylacetamide.
The reaction was carried out at 30 ° C for 50 hours. After the reaction, the reaction product was reprecipitated in a large amount of water to be recovered, dissolved in dimethyl sulfoxide,
The procedure of reprecipitation with water was repeated for purification, and drying to obtain a polyamide thioether prepolymer. Next, 0.01 g of phosphoric acid was added thereto, and solid-phase polymerization was performed at 160 ° C. for 10 hours under vacuum to obtain polyamide thioether. The obtained polymer was purified in the same manner as above. The solution viscosity of a 0.1 g / cm ³ solution of this polymer in concentrated sulfuric acid at 30 ° C. is 52
It was cm ³ / g.

[Synthesis Example 14] 14.75 g (0.25 mol) of ethanolamine, 22.0 g (0.25 mol) of ethyl acrylate and 0.4 g of lithium methoxide were added to 250 cm ³ of tetrahydrofuran and reacted at 25 ° C for 5 hours. The treatment after the reaction is performed in the same manner as in Synthesis Example 3, A polyamide ether having the following structure was obtained.

The solution viscosity of a 0.1 g / 10 cm ³ solution of this polymer in concentrated sulfuric acid at 34 ° C. was 34 cm ³ / g.

[Synthesis Example 15] 4.56 g (0.02 mol) of bisphenol A and triethylamine
4.07 g (0.05 mol) of 20.0 cm ³ of tetrahydrofuran (TH
Dissolve it in F), put it in an ice-cooled 100 cm ^{3 three-} necked flask, and stir it with a ^three-one motor.

On the other hand, 3,3'-thiodipropionic acid chloride 4.30 g
(0.02 mol), in which 20.0 cm ³ of THF had been dissolved, was added dropwise to the flask over about 30 minutes while stirring.

After reacting with stirring for about 1 hour, the reaction product was poured into purified water, and the polymer was recovered by filtration and washed several times with purified water. After refining by repeating the operation of dissolving in THF and reprecipitating with water, vacuum drying, A polymer having the following structure was obtained. The solution viscosity of this polymer is
I hung it at 21 cm ³ / g.

[Synthesis Example 16] 2.28 g (0.02 mol) of 2,5-dimethylpiperazine was added to 0.04 m
ol dissolved in 100 cm ³ of an aqueous solution containing sodium hydroxide, and put this into a reactor together with 4.30 g of 3,3-thiodipropionyl chloride (0.02 mol) dissolved in 100 cm ³ of chloroform. High speed stirring with ice cooling 5
Interfacial polymerization was carried out for a minute. The precipitate formed was recovered by filtration, dissolved in monochlorobenzene, and reprecipitated with methanol. A polymer having the following structure was obtained. This polymer in concentrated sulfuric acid 0.
1 g / 10 cm ³ solution The solution viscosity at 30 ° C. was 80 cm / g.

[Synthesis Example 17] 15 g of the polyamide thioether obtained in Synthesis Example 11 was added to 300 c.
It was dissolved in 90% formic acid (m ³⁾ , 30 cm ³ of 35% hydrogen peroxide was added dropwise while cooling with water, and the mixture was stirred for 30 minutes. The reaction product is poured into a large amount of water for reprecipitation, washed with water and acetone, and then dried under reduced pressure. A sulfonated polymer in which the following structure was partially introduced was obtained.

A solution of this polymer in a sulfuric acid 0.1 g / 10 cm ³ solution at 30 ° C. had a solution viscosity of 32 cm ³ / g.

[Synthesis Example 18] 15 g of the polyamide thioether obtained in Synthesis Example 11 was added to DMSO.
It was dissolved in a mixed solution of 200 cm ³ and the acetic acid 200 cm ^3, and the external while ice cooling potassium permanganate (KMnO ₄₎ was slowly added 2 hours with stirring 10g. After the reaction, purified water (500 cm ³⁾ was added to the reaction solution, and sodium bisulfite was added until the solution became colorless, and then the reaction product was recovered. The reaction product was washed with water and acetone and then dried under reduced pressure. A polymer having the following structure introduced into a part of the polymer was obtained. A solution of this polymer in a sulfuric acid 0.1 g / 10 cm ³ solution at 30 ° C. had a solution viscosity of 24 cm ³ / g.

[Synthesis Example 19] 1.0 g of the polyamide thioether obtained in Synthesis Example 11 was added to 30 cm ³ of dichloromethane, 2.0 g of trichloroacetic anhydride was added, and the mixture was reacted for 15 hours while stirring. Dichloromethane and trifluoroacetic acid were removed from the reaction solution using an evaporator to obtain a trifluoroacetylated polymer in which the structural unit shown below was partially introduced.

A solution of this polymer in a sulfuric acid 0.1 g / 10 cm ³ solution had a solution viscosity of 40 cm ³ / g at 30 ° C.

[Synthesis Example 20] 0.025 mol of the polyamide thioether obtained in Synthesis Example 11 was added to DMSO in which sodium hydride was dissolved at 70 ° C under a nitrogen atmosphere, and the mixture was reacted at 30 ° C for 4 hours while stirring. Next, 0.025 mol
Propyl bromide of was added and reacted at 30 ° C. for 16 hours with stirring. The reaction product is reprecipitated in a large amount of water, washed with water and acetone, and dried under reduced pressure. A polymer in which the following structure was partially introduced was obtained. Solution viscosity in sulfuric acid 0.1 g / 10 cm ³ solution 30 ° C. This polymer 27cm
^{It was 3} / g.

Synthesis Example 21 In Synthesis Example 21, instead of lactam thioether,
A polyamide copolymer having the following structure was obtained by repeating the procedure of Synthesis Example 2 except that a mixture of 5.65 g (0.05 mol) of ε-captolactam and 13.12 g (0.10 mol) of lactam thioether was used.

The solution viscosity of a 0.1 g / cm ³ solution of this copolymer in concentrated sulfuric acid at 30 ° C. was 30 cm ³ / g.

[Synthesis Example 22] 15.0 g of acetylenecarboxylic acid and 15.0 g of hexamethylenedithiol were subjected to Michael addition reaction in 1000 cm ³ of methanol with Triton B (trimethylbenzylammonium hydroxide) as a catalyst, and the both ends as shown below. A compound having a carboxyl group was obtained.

HOOC-CH = CH-S- ( CH 2) 6 -S-CH = CH-COOH allowed to stir reacting this compound in thionyl chloride to give the acid chloride obtained by chlorinating the carboxyl group.

The obtained acid chloride is subjected to polycondensation reaction with 2,5-dimethylpiperazine, A polyamide having the following structure was obtained.

100g of this polyamide 10.0g and methanethiol 3.0g
Dissolve in ³ dimethylsulfoxide (DMSO), AIBN 1m
g was added, and the mixture was reacted at 60 ° C. for several hours under a nitrogen stream. After the reaction, the polymer is reprecipitated in water for purification, A polymer having the following structure was obtained. 0.1 of this polymer in DMSO
The solution viscosity of the g / 10 cm ³ solution at 30 ° C. was 39 cm ³ / g.

Example 1 The polymer obtained in Synthesis Example 1 was dissolved in chlorobenzene,
A 0.2 μm filter was used to obtain a resist solution having a concentration of 7%. This resist solution was applied on a chromium mask substrate by a spinner coating method, and prebaked at 90 ° C. for 30 minutes to obtain a uniform resist film having a thickness of 5000Å. Next, a beam diameter of 0.25 μm and energy
Irradiated with an electron beam of 10 KeV. After irradiation was carried out while changing the exposure amount, this was immersed in benzene for 60 seconds for development, and rinsed with isopropyl alcohol to solubilize the irradiated portion. The minimum dose (that is, sensitivity) at which the residual film thickness becomes zero was 4 × 10 ⁻⁶ coulomb / cm ³ .

Further, using this resist, a resist film having a thickness of 5000 Å was obtained on a chromium mask substrate in the same manner as described above, and an electron beam having a beam diameter of 0.25 μm and an acceleration voltage of 10 KeV was used for 4 × 10 ^−6.
A pattern was drawn by irradiating with a dose of coulomb / cm ¹ . Further, this resist film was treated with benzene for 1 minute and developed, and washed with isopropyl alcohol for 30 seconds to form a resist pattern. This substrate is post-baked at 110 ° C for 30 minutes, then immersed in a wet etching solution of a chromium mask for 1 minute for etching, washed with water, and then treated for 20 minutes in oxygen plasma with a pressure of 2 Torr and an output of 400 W to resist the substrate. By assembling with the pattern, a photomask having a chrome pattern consisting of 0.5 μm lines and spaces was obtained, that is, the resolution was 0.5 μm.

[Example 2] The polymer obtained in Synthesis Example 9 was dissolved in DMF and passed through a 0.2 µm filter to obtain a resist solution having a concentration of 7%.

This resist solution was applied on a chromium mask substrate by a spinner coating method and prebaked at 90 ° C. for 30 minutes to obtain a uniform resist film having a thickness of 5000Å. Next, the resist film was irradiated with an electron beam having a beam diameter of 0.25 μm and an energy of 10 KeV at a dose of 5 × 10 ⁻⁵ coulomb / cm ² to draw a pattern. Further, this resist film was treated with dimethyl sulfoxide for 1 minute, developed, and washed with isopropyl alcohol for 1 minute to form a resist pattern.

Next, the substrate provided with the resist pattern is heated at 140 ° C. for 30 minutes.
After post-baking for a minute, this substrate was wet etched with a chromium mask (cerium ammonium nitrate 16
5 g, 70% perchloric acid 43 cm ³ pure water 1000 cm ³ ) for 1 minute for etching, washing with water, dipping the substrate in a peeling film consisting of sulfuric acid-hydrogen peroxide mixture at 70 ° C for 5 minutes, and then resist The pattern was peeled off to obtain a photomask having a chrome pattern consisting of 1 μm lines and spaces.

Example 3 The polymer obtained in Synthesis Example 11 was dissolved in formic acid and filtered through a 0.2 μm filter to obtain a resist solution having a concentration of 7%. This resist solution was applied onto a chromium mask substrate by a spinner coating method, and prebaked at 80 ° C. for 30 minutes to form a uniform resist film having a thickness of 5000Å.
Next, a beam diameter of 0.25 μm and an energy of 10
After irradiating the electron beam of KeV with 8 × 10 ^-6 coulomb / cm ² ,
A CF ₄ plasma treatment of Torr 100 W was performed to obtain a resist pattern. Then, etching was performed in the same manner as in Example 1 to remove the resist pattern to obtain a photomask having a chrome pattern composed of 0.5 μm lines and spaces.

Example 4 The polymer obtained in Synthesis Example 12 was dissolved in formic acid and filtered through a 0.2 μm filter to obtain a resist solution having a concentration of 7%.

This resist solution was applied on a chromium mask substrate by a spinner coating method, and prebaked at 80 ° C. for 30 minutes to form a uniform resist film having a thickness of 5000Å. Then, after irradiating an electron beam with energy of 10KeV to the resist film 8 × 10 ^-6 coulomb / cm ^2, DMSO: methanol = 3: developed with 2, a resist pattern was formed was washed with methanol.

Then, post-baking was performed at 140 ° C. for 30 minutes, and after etching, the resist pattern was peeled off in the same manner as in Example 1 to obtain a photomask having a chromium pattern having 0.5 μm lines and spaces.

Example 5 The polymer obtained in Synthesis Example 17 was treated with dimethyl sulfoxide (DM
SO) and passed through a 0.2 μm filter to obtain a resist solution having a concentration of 7%. Using this resist solution, the resist characteristics were evaluated in the same manner as in Example 1. As a result, at a resist film thickness of 5000Å, the sensitivity represented by the minimum irradiation amount at which the residual film ratio becomes zero is 5 × 10 ^-6 C / cm ² , and the line and space of 0.5 μm can be resolved, which is excellent. The resist characteristics are shown.

Example 6 The polymer obtained in Synthesis Example 19 was dissolved in chlorobenzene and passed through a 0.2 μm filter to obtain a resist solution having a concentration of 7%. This resist solution was applied on a silicon wafer having a silicon oxide film with a thickness of 1500 Å by a spinner coating method and prebaked at 90 ° C for 30 minutes to form a uniform resist film with a thickness of 5000 Å. Next, a beam diameter of 0.25 μm and an energy of 10
After irradiation with an electron beam of KeV at 2 × 10 ⁻⁶ coulomb / cm ² , the resist pattern was formed by treating with methyl ethyl ketone for 1 minute to develop and washing with isopropyl alcohol for 30 seconds. Then, after post-baking at 140 ℃ for 30 minutes, 40
% Aqueous solution of ammonium fluoride and 48% aqueous solution of hydrofluoric acid 1
Immerse in the etching solution obtained by mixing at a ratio of 0: 1,
Etching was carried out for 3 minutes. After etching, the wafer was treated with oxygen plasma under the conditions of 5 Torr and 300 W to remove the resist, and a silicon oxide film pattern consisting of lines and spaces of 1 μm each was obtained.

[Examples 7 to 15] The polymers obtained in Synthetic Examples 2 to 8, 10, 13 to 16, 18, and 20 to 21 were dissolved in respective solvents, and then applied on a chromium mask substrate in the same manner as in Examples 1 to 6. A resist film having a thickness of about 0.5 μm was formed and the resist characteristics were measured. The measurement results are shown in Table 1 below.

As is clear from the above measurement results, all showed excellent resist characteristics.

EFFECTS OF THE INVENTION As is clear from the results of the above examples, the ionizing radiation-sensitive positive resist of the present invention has high sensitivity and high resolution to ionizing radiation such as an electron beam, and It has excellent adhesion and developability. Therefore, the resist of the present invention is extremely useful for forming ultrafine patterns in the manufacturing process of high density integrated circuits such as LSI and VLSI.

Claims (1)

[Claims] 1. (a) A polymer obtained by a Michael-type polyaddition reaction between a compound having an unsaturated bond and a compound having an active hydrogen group, and (b) having an unsaturated bond and an active hydrogen group in the molecule. Polymer obtained by Michael-type polyaddition reaction of compound, (c) Polymer obtained by polymerization reaction of monomer formed by Michael addition reaction of compound having unsaturated bond and compound having active hydrogen group, or A copolymer obtained by a polymerization reaction of this monomer and another polymerizable monomer, (ii) the polymer (ii), (ii) or (ii) a derivative selected from the group consisting of: An ionizing radiation-sensitive positive resist, which comprises one or more polymers.