JPH024254A - Resist composition - Google Patents

Abstract

PURPOSE:To obtain a resist compsn. having well-balanced resist characteristics and being suitable to be used for lithography using short wavelength light such as far ultraviolet rays, KrF rays, excimer laser light, by incorporating a hydrogenated product of a specified alkali-soluble phenol resin and a photosensitive compd. into the compsn. CONSTITUTION:The title resist compsn. contains a hydrogenated product of an alkali-soluble phenol resin and a photosensitive compound. Said hydrogenated product of an alkali-soluble phenol resin is obtd. by hydrogenating a condensation produce of a phenolic compd. with an aldehydic compd., condensation product of a phenolic compd. with a ketonic compd., or an isopropenyl phenol type polymer. Suitable phenolic compd. to be used is phenol, cresol, pyrogallol, etc. Thus, a resist material having well-balanced characteristics such as sensitivity, resolution, etching resistance, preservation stability, etc., is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resist material for microfabrication of semiconductor devices.
This relates to a pattern-forming material that is formed by irradiation with light or the like.

(Prior art) When manufacturing semiconductor devices, a resist is applied to the surface of a silicon wafer to form a photoresist film, a latent image is formed by irradiation with light, and then a negative or positive image is formed by developing the latent image. Images are obtained using lithography technology.

However, with the increasing integration, density, and miniaturization of semiconductor devices such as ICs, LSIs, and even vLSIs, a technology for forming fine patterns of 1 μm or less is required. However, it is extremely difficult to accurately form a pattern of 1 μm or less using conventional photolithography using near ultraviolet or visible light.

At the same time, the yield is significantly reduced, so the method using ordinary photolithography cannot be used to form patterns of 1 μm or less.

For this reason, instead of conventional photolithography that uses light (ultraviolet rays with a wavelength of 350 to 450 nm), lithography techniques that use far ultraviolet rays with shorter wavelengths, KrF excimer laser light, and the like are being researched.

Sensitivity and resolution are the required performances for resist materials, which are central to this lithography technology.

There are wide-ranging requirements such as etching resistance and storage stability.
Conventionally developed materials do not fully satisfy all of these properties, and there is a strong desire for improved performance.

For example, negative resists such as polyglycidyl methacrylate have high sensitivity, but have poor resolution and dry etching resistance, and improvements are desired.

Further, although positive resists such as polymethyl methacrylate have good resolution, they have poor sensitivity and dry etching resistance, which poses a practical problem. Furthermore, when a novolac positive type photoresist used in conventional photolithography is exposed to deep ultraviolet rays, the resist itself absorbs too much light, making it impossible to form a good pattern. Therefore, the development of a new well-balanced resist is strongly desired.

(Problems to be Solved by the Invention) The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, improve sensitivity,
Well-balanced resist properties such as resolution, etching resistance, storage stability, etc., especially short-wavelength deep ultraviolet rays,
An object of the present invention is to provide a resist material suitable for lithography using KrF excimer laser light.

(Means for Solving the Problems) This object of the present invention is to produce an alkali selected from the condensation reaction products of phenols and aldehydes, the condensation reaction products of phenols and ketones, and isopropenylphenol polymers. This is achieved by a resist composition characterized by containing a hydrogenated product of a soluble phenolic resin and a photosensitive compound.

The hydrogenated product of alkali-soluble phenol resin used in the present invention is a condensation reaction product of phenols and aldehydes, a condensation reaction product of phenols and ketones, and an isopropenylphenol polymer. obtained by

Specific examples of phenols used here include phenol, cresol, xylenol, ethylphenol, phenylphenol, resorcinol, pyrocatechol,
Examples include hydroquinone, bisphenol A, pyrogallol, and the like.

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

Specific examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone, and the like.

These condensation reactions can be carried out according to conventional methods.

Further, the isopropenylphenol-based polymer is selected from a homopolymer of isopropenylphenol or a copolymer of isopropenylphenol and a copolymerizable component. Specific examples of copolymerizable components include acrylic acid derivatives, methacrylic acid derivatives, styrene derivatives, maleic anhydride, vinyl acetate, acrylonitrile, and the like. These copolymerizable components account for 0 to 80 mol% in the polymer.
used at a rate of

The hydrogenation reaction of the above alkali-soluble phenolic resin is as follows:
It can be carried out by any known method, and is achieved by dissolving the alkali-soluble phenolic resin in an organic solvent and introducing hydrogen in the presence of a homogeneous or heterogeneous hydrogenation catalyst. Ru. The concentration of the alkali-soluble phenolic resin solution is 1 to 70% by weight, preferably 1 to 40% by weight. There are no particular limitations on the solvent as long as it dissolves the resin to be subjected to the hydrogenation reaction without adversely affecting the catalyst. The hydrogenation catalyst used in the present invention is not particularly limited as long as it is a metal or nonmetallic catalyst that has hydrogenation reaction activity. As a specific example, p e + C01N 1 + Ru + Rh
+Pd, Ir, Os, Pt, Cr4eJn, Ti, V
, Zr, Mo, W, etc. These catalysts are
They can be used alone or in combination. Reaction temperature is 0-3
00°C, preferably 20 to 150°C. 30
A temperature of 0° C. or higher is acceptable, but side reactions occur and this is not preferable in terms of hydrogenation reaction. Reaction hydrogen pressure is atmospheric pressure ~ 400k
g/ad, preferably 5 to 200 kg/ad.
It is crl. After hydrogenation reaction, reprecipitation purification, sedimentation method,
The catalyst can be removed from the hydrogenation reaction resin solution by centrifugation, filtration, or the like.

The photosensitive compound used in the present invention is described in "Photosensitive Polymer J" by Gentabu Nagamatsu and Hideo Inui (1980), Kodansha (Tokyo), and "Photoresist" by DeForest (1975).
There is no particular limitation as long as it is described in McGraw-Hill Incorporated (New York), etc. Specific examples thereof include 1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, and 2,1-naphthoquinonediazide. -4-sulfonic acid ester, 2.1
-Naphthoquinone diazide-5-sulfonic acid ester or derivative thereof, 2-diazo-cyclohexane-
1,3-dione, 5-diazo-Meldrum acid ester,
3-Diazo-pyrrolidine-2,4-dione.

Diazoketone compounds such as 3-cyasypiperidine-2,4-dione, diazophosphenylketone compounds or derivatives thereof, 0-nitrobenzyl ester, 0
- 0-nitrobenzyl compounds such as nitrobenzyl sulfonic acid ester, 0.0-dinitrobenzyl ester, 0.0-dinitrobenzyl sulfonic acid ester, onium salts such as iodonium salt, phosphonium salt, sulfonium salt, ammonium salt, l-azidopyrene , p-azidobenzophenone, 4'-methoxy-4-azidodiphenylamine, 4-azidobenzal-2'-methoxyacetophenone, 4-azido-4'-nitrophenylazobenzene and other monoazide compounds, 4,4'-diazidobenzophenone , 4.4′-diazidebenzomethane,
4.4-Diazidostilbene.

4.4-diazidochalcone, 4.4-diazidodiphenylsulfone, 3,4-diazidodiphenylsulfone, 3.3-diazidodiphenylsulfone.

Examples include bisazide compounds such as 2,6-di(4'-azidobenzal)cyclohexanone and 2,6-di(4'-azidobenzal)4-methylcyclohexanone, monosulfonyl azide compounds, and bissulfonyl azide compounds.

The blending amount of these photosensitive compounds is 1 to 100 parts by weight, preferably 3 to 100 parts by weight, based on 100 parts of the above polymer.
It is 30 parts by weight. If it is less than 1 part by weight, it will be impossible to form a pattern, and if it exceeds 10,031 parts by weight, residual development will likely occur.

The resist composition of the present invention is used by dissolving the hydrogenated alkali-soluble phenol resin and photosensitive compound in a solvent. Examples of solvents include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, cellosolve esters such as methyl cellosolve acetate and ethyl cellosolve acetate-1, toluene, xylene, etc. Examples include aromatic hydrocarbons. These may be used alone, but two or more types may be mixed.

Furthermore, a surfactant, a storage stabilizer, a sensitizer, an anti-striation agent, etc. can be added to the resist composition of the present invention, if necessary.

An aqueous alkali solution is used as a developer for the resist composition of the present invention, and specifically, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, primary amines such as ethylamine propylamine, etc. tertiary amines such as diethylamine and dipropylamine, tertiary amines such as trimethylamine and triethylamine, alcohol amines such as diethylethanolamine and triethanolamine, tetramethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide, Examples include quaternary ammonium salts such as tetraethylammonium hydroxide.

Furthermore, if necessary, add methanol or
Appropriate amounts of water-soluble organic solvents such as ethanol, propatool, and ethylene glycol, surfactants, and resin dissolution inhibitors can be added.

(Example) The present invention will be described in more detail with reference to Examples below. In addition, parts and percentages in the examples are based on weight unless otherwise specified.

Synthesis Example 1 50 g of +11+p-talesol novolak (hereinafter abbreviated as NVK) and 450 g of ethanol were charged into an autoclave and mixed well to dissolve the polymer. Then Raney Ni
After adding 6 g of hydrogen and purging the system with nitrogen, hydrogen pressure was applied at 50 kg/cj and maintained at 20° C. for 30 minutes. Thereafter, this autoclave was placed in a hot bath at 50° C. and reacted for 3 hours. Raney Ni was filtered off from the solution after the reaction, and the reaction solution was poured into water to precipitate a polymer. Furthermore, the obtained polymer was dissolved in ethanol and poured into water to precipitate the polymer. Next, this polymer was dissolved in dioxane and freeze-dried for 36 hours to obtain a dry polymer. The yield was 90%.

Gel permeation chromatography of the above polymer
(GPC) measurement result Mw=6000. As a result of nuclear magnetic resonance spectrum (NMR) measurement, the hydrogenation rate was 30%. In addition, as a result of UV spectrum measurement, hydrogenated NVK has a transmittance of about 2 at 250 nm compared to the raw material NVK.
improved twice.

Synthesis Example 2 A condensate of pyrogallol and acetone (hereinafter abbreviated as PA) was treated under the same conditions as in Synthesis Example 1 to obtain a dry polymer. The yield was 90%.

Gel permeation chromatography of the above polymer
(GPC) measurement result Mw = 4000, nuclear magnetic resonance spectrum (NMR) measurement result, hydrogenation rate is 25%
Met. In addition, as a result of UV spectrum measurement, raw material P
Compared to A, the transmittance of hydrogenated PA at 250 nm was approximately doubled.

Synthesis Example 3 50 g of a copolymer of 80 mol% isopropenylphenol and 20 mol% styrene (hereinafter abbreviated as rpp/st) and 450 g of ethanol were placed in an autoclave and mixed well to dissolve the polymer.

Next, 4 g of Raney Ni was added, and after purging the system with nitrogen, hydrogen pressure was applied at 50 kg/cJ while maintaining the temperature at 20°C for 30
It lasted for a minute. Thereafter, this autoclave was placed in a hot bath at 40° C. and reacted for 5 hours. Raney N from the solution after reaction
i was filtered off, and the reaction solution was poured into water to precipitate a polymer. Furthermore, the obtained polymer was dissolved in ethanol and poured into water to precipitate the polymer. Next, this polymer was dissolved in dioxane and freeze-dried for 40 hours to obtain a dry polymer. The yield was 95%.

Gel permeation chromatography of the above polymer
As a result of (GPC) measurement, Mw=8000, and as a result of nuclear magnetic resonance spectrum (NMR) measurement, the hydrogenation rate was 20%. In addition, as a result of UV spectrum measurement, the raw material IPP
/St, hydrogenated IPP/St has a thickness of 250 nm.
The transmittance was approximately doubled.

100 parts of hydrogenated NVK from Synthesis Example 1, 70% of the 10H group of 2,3゜4-trihydroxybenzophenone
The above is an ester of 1.2-naphthoquinonediazide-4-sulfonic acid. 20 parts of the quinonediazide compound is dissolved in 400 parts of ethyl cellosol acetate, and the resist solution is filtered through a 0.1 μm Teflon filter (manufactured by Millipore). Prepared.

After applying the above resist solution onto a silicon wafer using a spinner, the resist solution was incubated at 85°C for 20 minutes to a thickness of 0.9 μm.
A resist film was formed. This wafer was exposed to light using a far ultraviolet irradiation device PLA-521FA (manufactured by Canon) and a test mask. Next, the film was developed by dipping in a tetramethylammonium hydroxide aqueous solution at 23° C. for 1 minute to obtain a positive pattern.

When the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.4 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 (manufactured by Tenko Corporation) and was found to be 0.8 μm.

Further, the patterned wafer was dry-etched using a dry etching device DEM-4517 (manufactured by Nikkei Anelva Co., Ltd.) at a power of 300 W, a pressure of 0.03 Torr, and a % gas CF4/H=30/10. Frequency 13.56 MHz
When etching was performed, it was observed that only the areas where there was no pattern were etched.

Dog, If! 1 (JI+2 NVK (Mw=
4000, hydrogenation rate 45%) 100 parts.

12 parts of 2-diazo-cyclohexane-1,3-dione was dissolved in 400 parts of ethyl cellosolve acetate, and 0.1
A resist solution was prepared by filtration with a μm Teflon filter.

After applying the above resist solution onto a silicon wafer with a spinner, it was incubated at 75°C for 10 minutes to a thickness of 1.0 μm.
A resist film was formed. This wafer was exposed to light using a far ultraviolet irradiation device PLA-521FA and a test mask. Next, the film was developed by dipping in a tetramethylammonium hydroxide aqueous solution at 23° C. for 21 minutes to obtain a positive pattern.

When the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.45 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was found to be 0.8 μm.

Daizai 1 Tsu 1 Hydrogenated NVK (Mw
= 6000, hydrogenation rate 30%) 100 parts.

A resist solution was prepared by dissolving 25 parts of 5-diazomeldrum's acid in 400 parts of ethyl cellosolve acetate and filtering through a 0.1 μm Teflon filter.

After applying the above resist solution onto a silicon wafer using a spinner, it was betatized at 70°C for 10 minutes to a thickness of 0.8 μm.
A resist film was formed. This wafer was exposed to light using a far ultraviolet irradiation device PLA-521FA and a test mask. Next, the film was developed by dipping in a tetramethylammonium hydroxide aqueous solution at 23° C. for 1 minute to obtain a positive pattern.

When the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.45 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was found to be 0.7 μm.

100 parts of NVK used in Example 2, 18 parts of 0.0 dinitrocholate, and 0.02 parts of fluorinated surfactant were dissolved in 400 parts of cyclohexanone, and filtered with a 0.1 μm Teflon filter. A resist solution was prepared.

After applying the above resist solution onto a silicon wafer using a spinner, it was betatized at 80°C for 10 minutes to a thickness of 0.9 μm.
A resist film was formed. This wafer was exposed to light using a far ultraviolet irradiation device PLA-521FA and a test mask. Next, it was developed by dipping in an aqueous solution of tetramethylammonium hydroxide at 23"C for 1 minute to obtain a positive pattern.

When the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.45 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was found to be 0.7 μm.

Example 41 Crude I 100 parts of the hydrogenated PA of Synthesis Example 2 and 10 parts of diphenyliodonium tetrafluoroborate were dissolved in 400 parts of ethyl cellosolve acetate and filtered through a 0.1 μm Teflon filter to prepare a resist solution.

After applying the above resist solution onto a silicon wafer with a spinner, it was betatized at 80°C for 10 minutes to a thickness of 1.0 μm.
A resist film was formed. Transfer this wafer to krypton/
Excimer laser device C292 filled with fluorine gas
6 (manufactured by Hamamatsu Photonics) and a test mask. Next, the film was developed by dipping in a tetramethylammonium hydroxide aqueous solution at 23°C for 1 minute to obtain a positive pattern.

When the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.45 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was found to be 0.9 μm.

SM shadow 100 parts of hydrogenated IPP/5t of Synthesis Example 3.

2.3.4-) 19 parts of a quinonediazide compound in which 70% of the 10H groups of lyhydroxyacetophenone are esters of 1,2-naphthoquinonediazide-4-sulfonic acid;
0.02 parts of fluorosurfactant and 40 parts of cyclohexanone
A resist solution was prepared by dissolving the resist solution in 0 parts and filtering it through a 0.1 μm Teflon filter.

After applying the above resist solution onto a silicon wafer with a spinner, it was betatized at 80°C for 10 minutes to a thickness of 1.0 μm.
A resist film was formed. Transfer this wafer to krypton/
Excimer laser device C292 filled with fluorine gas
Exposure was performed using No. 6 and a test mask. Next, with an aqueous solution of tetramethylammonium hydroxide at 23°C,
The film was developed by dipping for a few minutes to obtain a positive pattern.

When the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.45 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was 0.7 μm. Hydrogenated isopropenylphenol polymer (hereinafter abbreviated as IPP) prepared in the same manner as Synthesis Example 3.

Mw 8000, hydrogenation rate 20%) 100 parts, 4.
A resist solution was prepared by dissolving 12 parts of 4'-diazide diphenyl sulfone and 0.02 part of a fluorine-based surfactant in 400 parts of cyclohexanone and filtering through a 0.1 μm Teflon filter.

After applying the above resist solution onto a silicon wafer with a spinner, it was betatized at 80°C for 10 minutes to a thickness of 1.0 μm.
A resist film was formed. Transfer this wafer to krypton/
Excimer laser device C292 filled with fluorine gas
Exposure was performed using No. 6 and a test mask. Next, with an aqueous solution of tetramethylammonium hydroxide at 23°C,
It was developed by dipping for 1 minute to obtain a negative pattern.

When the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.45 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was found to be 0.9 μm.

, Comparison 10 - After applying a regular commercially available novolak positive photoresist onto a silicon wafer using a spinner,
The mixture was betatized for a minute to form a resist film with a thickness of 1.0 μm. This wafer was exposed to light using an excimer laser device C2926 filled with krypton/fluorine gas and a test mask.

Next, the film was developed by dipping in a tetramethylammonium hydroxide aqueous solution at 23° C. for 1 minute to obtain a positive pattern.

When the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.55 μm were resolved, but the lines were severely thinned and the pattern shape was poor, causing practical problems.

Comparison l Raw material before hydrogenation of Example 7 100 parts of PP, 12 parts of 4.4'-diazide diphenyl sulfone, and 0.02 part of fluorine surfactant were dissolved in 400 parts of cyclohexanone,
0. A resist solution was prepared by filtration using a IIJm Teflon filter.

Patterning was performed in the same manner as in Example 7, and when the patterned wafer was taken out and observed under an electron microscope, lines and spaces of 0.65 μm were resolved, but the pattern shape was poor. .

(Effects of the Invention) According to the present invention, a resist material with well-balanced sensitivity, resolution, etching resistance, storage stability, etc. can be obtained.

Patent applicant: Zeon Corporation

Claims (1)

[Claims] (1) Contains hydrogenated products of alkali-soluble phenolic resins selected from condensation reaction products of phenols and aldehydes, condensation reaction products of phenols and ketones, and isopropenylphenol polymers, and photosensitive compounds. A resist composition characterized by comprising: