JPH087435B2 - Positive resist composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a positive resist composition, and more specifically, a positive resist for microfabrication required for manufacturing semiconductor devices, magnetic bubble memory devices, integrated circuits, and the like. The present invention relates to a resist composition.

(Prior Art) When manufacturing a semiconductor, a resist is applied to the surface of a silicon wafer to form a photosensitive film, which is irradiated with light to form a latent image, which is then developed to form a negative or positive image. The semiconductor element is formed by the lithographic technique.

Conventionally, as a resist composition for forming a semiconductor element, a negative resist composed of cyclized polyisoprene and a bisazide compound has been known. However, since this negative resist is developed with an organic solvent, it swells greatly and has a limitation in resolution, and thus has a disadvantage that it cannot cope with the manufacture of a highly integrated semiconductor. On the other hand, in contrast to this negative resist composition, the positive resist composition is considered to be sufficiently compatible with high integration of semiconductors because of its excellent resolution.

At present, the positive resist composition generally used in this field comprises a novolac resin and a quinonediazide compound.

However, conventional positive resist compositions have not always obtained satisfactory results in various characteristics such as sensitivity, resolution, residual film rate, heat resistance, and storage stability, and improvement in performance is strongly desired. . In particular, sensitivity is important for improving the productivity of semiconductors, and it is strongly desired to improve the sensitivity of positive resist compositions. For this purpose, various compounds are added in addition to the novolak resin and the quinonediazide compound, which are base components of the positive resist composition. Examples of compounds added for the purpose of increasing sensitivity, that is, sensitizers, include nitrogen heterocyclic compounds such as halogenated benzotriazole derivatives (JP-A-58-37).
641) and cyclic acid anhydrides (Japanese Patent Publication No. 56-30850)
Is mentioned. However, the addition of these sensitizers eliminates the difference in solubility between exposed and unexposed areas, resulting in a decrease in the residual film ratio, deterioration in resolution, and plasticization of the novolak resin by the sensitizer. There arises a problem such as a decrease in heat resistance due to the activating effect.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to be excellent in various properties such as sensitivity, resolution, residual film rate, heat resistance, and storage stability, in particular 1 μm or less Another object of the present invention is to provide a high-sensitivity positive resist composition suitable for fine processing.

This object of the present invention is achieved by incorporating a specific phenol compound into a positive resist composition containing an alkali-soluble phenol resin and a quinonediazide sulfonic acid ester-based photosensitizer.

(Means for Solving the Problems) Thus, according to the present invention, an alkali-soluble phenol resin, a quinonediazide sulfonic acid ester-based photosensitizer,
And a positive resist composition comprising the compound represented by the general formula (I) is provided.

(R _{1 to} R ₁₀ are a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms,
Alternatively, it may be a substituted or unsubstituted alkoxy group having 1 to 3 carbon atoms, which may be the same or different. Hereinafter, the present invention will be described in detail.

Alkali-soluble phenol resin Examples of the alkali-soluble phenol resin used in the present invention include condensation reaction products of phenols and aldehydes, condensation reaction products of phenols and ketones, vinylphenol polymers, isopropenyl. Examples include phenolic polymers and hydrogenation reaction products of these phenolic resins.

Specific examples of phenols used here include phenol, cresol, xylenol, ethylphenol,
Examples include monohydric phenols such as propylphenol, butylphenol, and phenylphenol; polyhydric phenols such as resorcinol, pyrocatechol, hydroquinone, bisphenol A, and pyrogallol.

Specific examples of aldehydes used here include formaldehyde, acetaldehyde, benzaldehyde, and terephthalaldehyde.

Specific examples of the ketones used here include acetone,
Methyl ethyl ketone, diethyl ketone, diphenyl ketone, etc. are mentioned.

These condensation reactions can be performed according to a conventional method such as bulk polymerization or solution polymerization.

The vinylphenol polymer is selected from a homopolymer of vinylphenol and a copolymer of vinylphenol and a component copolymerizable with vinylphenol. Specific examples of the copolymerizable component include acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, vinyl acetate, acrylonitrile, and derivatives thereof.

The isopropenylphenol-based polymer is selected from isopropenylphenol homopolymers and copolymers with isopropenylphenol-copolymerizable components. Specific examples of the copolymerizable component include acrylic acid,
Methacrylic acid, styrene, maleic anhydride, maleic imide, vinyl acetate, acrylonitrile, and derivatives thereof may be mentioned.

The hydrogenation reaction of these phenol resins can be carried out by any known method, such that the phenol resin is dissolved in an organic solvent and hydrogen is added in the presence of a homogeneous or heterogeneous hydrogenation catalyst. It can be achieved by introducing.

It is also possible to use those alkali-soluble phenol resins whose molecular weight distribution is controlled by reprecipitation fractionation or the like. In addition, these phenolic resins are
Although they can be used alone, two or more kinds may be mixed and used.

In the positive resist composition of the present invention, if necessary,
In order to improve developability, storage stability, heat resistance, etc., for example, a copolymer of styrene and acrylic acid, methacrylic acid or maleic anhydride, a copolymer of alkene and maleic anhydride, a vinyl alcohol polymer. , Vinylpyrrolidone polymer, rosin, shellac and the like can be added. The amount of addition is 10
It is 0 to 50 parts by weight, preferably 5 to 20 parts by weight, relative to 0 parts by weight.

Quinonediazidesulfonic acid ester-based photosensitizer The photosensitizer used in the present invention is not particularly limited as long as it is a quinonediazidesulfonic acid ester. As specific examples thereof, the ester moiety is 1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,1 −
Naphthoquinonediazide-4-sulfonic acid ester, 2,1
Examples include compounds such as naphthoquinonediazide-5-sulfonic acid ester and sulfonic acid esters of other quinonediazide derivatives.

Quinone diazide sulfonic acid ester can be generally synthesized by an esterification reaction between a compound having a hydroxyl group and a quinone diazide sulfonic acid compound. Can be obtained by the method of condensing a compound with a hydroxyl group [Mototaro Nagamatsu, Hideo Inui "Photosensitive Polymer"
(1980) Kodansha (Tokyo), etc.].

The sensitizer in the present invention may be used alone,
You may mix and use 1 or more types. The compounding amount of the photosensitizer is usually 1 to 100 parts by weight, preferably 3 to 40 parts by weight, based on 100 parts by weight of the alkali-soluble phenol resin. If it is less than 1 part by weight, it becomes impossible to form a pattern, and if it exceeds 100 parts by weight, undeveloped portions tend to occur.

Sensitizer The sensitizer used in the present invention is not particularly limited as long as it is a compound represented by the general formula (I).

Specific examples of the compound represented by formula (I) include the following.

The sensitizer in the present invention may be used alone,
You may use it in mixture of 2 or more types. The compounding amount of the sensitizer is usually 1 to 100 parts by weight, preferably 2 to 50 parts by weight, based on 100 parts by weight of the alkali-soluble phenol resin. If the amount added exceeds 100 parts by weight, the residual film rate will decrease drastically, making pattern formation difficult.

Other Components The positive resist composition of the present invention is used by dissolving it in a solvent, and examples of the solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone and cyclopentanone; n-propyl alcohol, iso-propyl alcohol. , N-butyl alcohol, cyclohexanol and other alcohols; ethylene glycol dimethyl ether, ethylene glycol dimethyl ether, dioxane and other ethers; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and other alcohol ethers; propyl formate, butyl formate, acetic acid Esters such as propyl, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl butyrate, ethyl butyrate, methyl lactate, ethyl lactate; cellosolve acetate Cellosolve esters such as methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate;
Propylene glycols such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, Diethylene glycols such as diethylene glycol diethyl ether and diethylene glycol methyl ethyl ether; halogenated hydrocarbons such as trichloroethylene; aromatic hydrocarbons such as toluene and xylene; dimethylacetamide, dimethylformamide, N-methylacetamide and the like Sex solvent; and the like. You may use these individually or in mixture of 2 or more types.

The positive resist composition of the present invention contains surfactants, storage stabilizers, and other compatible additives such as sensitizers, striation inhibitors, plasticizers, and antihalation agents as necessary. Can be done.

Developer Solution As a developer solution of the positive resist composition of the present invention, an aqueous alkali solution is used, and specific examples thereof include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, and ammonia; ethylamine, propylamine. Primary amines such as; secondary amines such as diethylamine and dipropylamine; tertiary amines such as trimethylamine and triethylamine; alcohol amines such as diethylethanolamine and triethanolamine;
Quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, and trimethylhydroxyethylammonium hydroxide; and the like.

If necessary, a suitable amount of a water-soluble organic solvent such as methanol, ethanol, propanol, or ethylene glycol, a surfactant, a storage stabilizer, a resin dissolution inhibitor, or the like can be added to the above-mentioned alkali water-soluble substance.

(Example) Below, an Example and a comparative example are given and this invention is demonstrated still more concretely.

Comparative Example 1 m-cresol and p-cresol were mixed at a molar ratio of 4: 6, formalin was added to the mixture, and 100 parts by weight of a novolak resin obtained by condensing by a conventional method using an oxalic acid catalyst. , 2,3,4,4'-Tetrahydroxybenzophenone, 75% of which is an ester of 1,2-naphthoquinonediazide-5-sulfonic acid, a quinonediazidesulfonic acid ester 28
Parts by weight and 350 parts by weight of ethyl cellosolve acetate to dissolve 0.1 μm of tetrafluoroethylene (hereinafter referred to as PTFE
It abbreviated) and was filtered with a filter to prepare a resist solution.

The resist solution was coated on a silicon wafer with a coater and baked at 100 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer is g-line stepper NSR
Exposure was performed using a -1505G6E (manufactured by Nikon Corporation, NA = 0.54) and a test reticle. Next, this wafer is treated with a 2.38% tetramethylammonium hydroxide aqueous solution at 23 ° C.
It was developed by a paddle method for 1 minute to obtain a positive pattern.

The sensitivity was evaluated to be 120 mJ / cm ² , and the film thickness of the pattern was measured with a film thickness meter Alphastep 200 (manufactured by Tenko Co.) to be 1.12 μm.

Example 1 A compound of formula (10) (sensitizer) was added to the resist solution of Comparative Example 1 at a ratio of 10 parts by weight to 100 parts by weight of a novolak resin and dissolved, followed by filtration through a 0.1 μm PTFE filter. Then, a resist solution was prepared.

This resist solution was treated in the same manner as in Comparative Example 1 to obtain a positive pattern.

When the wafer on which the pattern was formed was taken out and the sensitivity was evaluated, it was 80 mJ / cm ² , and when observed with an electron microscope,
The line and space of 0.54 μm were resolved. The film thickness of the pattern is measured by the film thickness meter Alpha Step 200 (manufactured by Tenko).
It was 1.13 μm. It was found that the sensitivity was improved as compared with the resist of Comparative Example 1.

Further, using a dry etching device DEM-451T (manufactured by Nidec Arneva) on the wafer on which this pattern is formed, power 300 W, pressure 0.03 Torr, gas CF ₄ / H = 3/1, frequency 13.
When it was etched at 56 MHz, it was observed that only the part without the pattern was etched.

Example 2 After coating the resist solution of Example 1 on a silicon wafer with a coater, baking was performed at 90 ° C. for 90 seconds to give a thickness of 1.17 μm.
Was formed. This wafer is a g-line stepper
Exposure was performed using NSR-1505G6E and a test reticle. Next, this wafer was subjected to PEB (Post Expos
ure Baking), and developed with a 2.38 tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a paddle method to obtain a positive pattern.

When the wafer on which the pattern was formed was taken out and the sensitivity was evaluated, it was 70 mJ / cm ² , and when observed with an electron microscope,
The line and space of 0.40 μm were resolved. 1.14 when the film thickness of the pattern is measured with the film thickness meter Alpha Step 200
was μm.

Examples 3 to 5 and Comparative Example 2 m-cresol, p-cresol and 3,5-xylenol were mixed at a molar ratio of 50:20:30, to which formalin was added and an oxalic acid catalyst was used. 100 parts by weight of novolak resin obtained by condensation by a conventional method, and quinonediazide sulfonic acid ester in which 95% of 2,3,4,4'-tetrahydroxybenzophenone is an ester of 1,2-naphthoquinonediazide-5-sulfonic acid 28 parts by weight and 5 parts by weight of the compound (sensitizer) shown in Table 1 were dissolved in 360 parts by weight of ethyl lactate and filtered through a 0.1 μm PTFE filter to prepare a resist solution.

The resist solution was coated on a silicon wafer with a coater and baked at 90 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer is g-line stepper NSR-1
Exposure was performed using the 505G6E and a test reticle. Next, after PEB the wafer at 110 ° C. for 60 seconds, it is treated with a 2.38% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 second.
Development was performed by the paddle method for 1 minute to obtain a positive pattern.

Table 1 shows the result of evaluation by taking out the wafer having the pattern formed thereon.

Example 6 100 parts by weight of novolak resin obtained by mixing m-cresol and p-cresol in a molar ratio of 8: 2, adding formalin thereto, and condensing by a conventional method using an oxalic acid catalyst. Dissolved in 400 parts by weight of ethyl cellosolve acetate,
This was dropped into 3000 parts by weight of toluene to precipitate a resin. The precipitated resin was separated by filtration and then vacuum dried at 60 ° C. for 30 hours. 100 parts by weight of vacuum dried resin, 2,3,4,4'-
28 parts by weight of a quinonediazide compound in which 95% of tetrahydroxybenzophenone is an ester of 1,2-naphthoquinonediazide-5-sulfonic acid, and 10 parts by weight of a compound (sensitizer) represented by formula (12) (380 parts by weight of ethyl lactate) And then filtered through a 0.1 μm PTFE filter to prepare a resist solution.

The resist solution was coated on a silicon wafer with a coater and baked at 90 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer is g-line stepper NSR-1
Exposure was performed using the 505G6E and a test reticle. Next, after PEB the wafer at 110 ° C. for 60 seconds, it is treated with a 2.38% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 second.
Development was performed by the paddle method for 1 minute to obtain a positive pattern.

When the wafer on which the pattern was formed was taken out and the sensitivity was evaluated, it was 90 mJ / cm ² , and when observed with an electron microscope,
The line and space of 0.45 μm were resolved. When the film thickness of the pattern is measured with the film thickness meter Alpha Step 200, it is 1.1.
It was 2 μm.

Example 7 Copolymer of vinylphenol and styrene (molar ratio 5:
5) 100 parts, 90 of Trisphenol PA (Mitsui Petrochemical)
% Of 1,2-naphthoquinonediazide-5-sulfonic acid ester was added to 36 parts by weight of a quinonediazide compound, and 5 parts by weight of a compound represented by the formula (9) (sensitizer) was added to diglyme.
It was dissolved in 320 parts by weight and then filtered through a 0.1 μm PTFE filter to prepare a resist solution.

The resist solution was coated on a silicon wafer with a coater and baked at 100 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer is an i-line stepper NSR
-Exposure was performed using the -1505i6A and a test reticle.
Next, this wafer was PEBed at 110 ° C. for 60 seconds, and then with a 2.38% tetramethylammonium hydroxide aqueous solution at 23 ° C.
It was developed by a paddle method for 1 minute to obtain a positive pattern.

When the wafer on which the pattern was formed was taken out and the sensitivity was evaluated, it was 90 mJ / cm ² , and when observed with an electron microscope,
The line and space of 0.50 μm were resolved. When the film thickness of the pattern is measured with the film thickness meter Alpha Step 200, it is 1.1.
It was 2 μm.

(Effects of the Invention) Since the positive resist composition of the present invention is excellent in sensitivity, resolution, residual film rate, heat resistance, storage stability, etc., it is particularly useful for fine processing of 1 μm or less.

Claims (1)

[Claims] 1. A positive resist composition containing an alkali-soluble phenol resin, a quinonediazide sulfonate ester-based photosensitizer, and a compound represented by the general formula (I). (R _{1 to} R ₁₀ are a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms,
Alternatively, it may be a substituted or unsubstituted alkoxy group having 1 to 3 carbon atoms, which may be the same or different. )