JPH03200251A - Positive type resist composition - Google Patents

Abstract

PURPOSE:To improve sensitivity, resolution, heat resistance, shelf stability, the rate of a residual film, etc., by incorporating alkali-soluble phenol resin, a quinonediazidosulfonic ester type photosensitive agent and a specified compd. CONSTITUTION:This positive type resist compsn. contains alkali-soluble phenol resin, a quinonediazidosulfonic ester type photosensitive agent and a compd. represented by formula I, wherein each of R1-R6 is H, halogen, alkyl or alkoxy, each of R7 and R8 is H, alkyl or hydroxyalkyl and n is 1-4. Sensitivity, resolution, heat resistance, shelf stability, the rate of a residual film, etc., are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a positive resist composition, and more particularly, to a positive resist composition for microfabrication necessary for manufacturing semiconductor devices, magnetic bubble memory devices, integrated circuits, etc. The present invention relates to a resist composition.

(Prior art) When manufacturing semiconductors, a resist is applied to the surface of a silicon wafer to create a photoresist film, and a latent image is formed by irradiating the film with light.
Semiconductor elements are formed by lithography technology in which the image is then developed to form a negative or positive image.

Conventionally, as a resist composition for forming a semiconductor element, a negative resist composed of cyclized polyisoprene and a bisazide compound is known.

However, since this negative resist is developed with an organic solvent, it has a drawback that it cannot be used in the manufacture of highly integrated semiconductors because it swells significantly and has a limited resolution. on the other hand,
In contrast to this negative resist composition, a positive resist composition has excellent resolution and is therefore considered to be able to sufficiently cope with high integration of semiconductors.

Currently, positive resist compositions commonly used in this field are composed of a novolac resin and a quinonediazide compound.

However, conventional positive resist compositions lack sensitivity,
Satisfactory results have not always been obtained with respect to various properties such as resolution, residual film rate, heat resistance, and storage stability, and improvements in performance are strongly desired. In particular, sensitivity is important for improving semiconductor productivity, and there is a strong desire for higher sensitivity of positive resist compositions. For this purpose, various compounds are added in addition to the novolac resin and quinonediazide compound, which are the base components of the positive resist composition.

Examples of compounds, ie, sensitizers, added to increase sensitivity include nitrogen heterocyclic compounds such as halogenated benzotriazole derivatives (Japanese Patent Laid-Open No. 58-376
41) and cyclic acid anhydrides (Japanese Patent Publication No. 56-30850). However, with the addition of these sensitizers, there is no difference in solubility between the exposed and unexposed areas (this results in a decrease in the remaining film rate, deterioration of resolution, and plasticization of the novolac resin by the sensitizer). Due to this effect, problems arise such as a decrease in heat resistance.

(Objects to be Solved by the Invention) The objects of the present invention are to solve the above-mentioned drawbacks of the prior art, improve sensitivity,
The object of the present invention is to provide a highly sensitive positive resist composition that has excellent properties such as resolution, residual film rate, heat resistance, and storage stability, and is particularly suitable for microfabrication of 1 μm or less.

(Means for Solving the Problems) This object of the present invention is to provide an alkali-soluble phenolic resin,
This is achieved by a positive resist composition containing a quinonediazide sulfonic acid ester photosensitizer and a compound represented by general formula (1).

R1-R6; Same or different, hydrogen, halogen, alkyl group or alkoxy group R7, R, Same or different, hydrogen, alkyl group or hydroxyalkyl group n = 1.2.3 or 4 In the present invention Examples of the alkali-soluble phenolic resins used include condensation reaction products of phenols and aldehydes, condensation reaction products of phenols and ketones, vinylphenol polymers, isopropenylphenol polymers, and the like. Examples include hydrogenation reaction products of phenolic resins.

Here, specific examples of the phenols used include monovalent phenols such as phenol, cresol, xylenol, ethylphenol, propylphenol, butylphenol, and phenylphenol, and polyvalent phenols such as resorcinol, pyrocatechol, hydroquinone, and bisphenol A1 pyrogallol. Examples include phenols.

Here, specific examples of the aldehydes used include formaldehyde, acetaldehyde, benzaldehyde, and terephthalaldehyde.

Here, specific examples of ketones used include acetone,
Examples include methyl ethyl ketone, diethyl ketone, and diphenyl ketone.

These condensation reactions can be carried out according to conventional methods such as bulk polymerization and solution polymerization.

Moreover, the vinylphenol-based polymer is selected from a homopolymer of vinylphenol and a copolymer of vinylphenol and a copolymerizable component. Specific examples of copolymerizable components include acrylic acid derivatives, methacrylic M derivatives,
Examples include styrene derivatives, maleic anhydride, maleic acid imide derivatives, vinyl acetate, and acrylonitrile.

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

The hydrogenation reaction of these phenolic resins can be carried out by any known method, in which the phenolic resin is dissolved in an organic solvent and hydrogen is released in the presence of a homogeneous or heterogeneous hydrogenation catalyst. This can be achieved by introducing

It is also possible to use these alkali-soluble phenol resins whose molecular weight distribution has been controlled by reprecipitation fractionation or the like. Further, these phenol resins can be used alone, but two or more types may be used in combination.

If necessary, the positive resist composition of the present invention may contain, for example, a copolymer of styrene and acrylic acid, methacrylic acid, or maleic anhydride to improve developability, storage stability, heat resistance, etc. , copolymers of alkenes and maleic anhydride, vinyl alcohol polymers, vinyl pyrolidra polymers, rosin shellac, etc. can be added.

The amount added is 0 to 50 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the alkali-soluble phenol resin.

The photosensitizer used in the present invention is not particularly limited as long as it is a quinonediazide sulfonic acid ester. As specific examples, the ester moiety is 1,2-benzoquinonediazide-4-sulfonic acid ester, 1.2-naphthoquinonediazide-4-sulfonic acid ester, 1.2-benzoquinonediazide-4-sulfonic acid ester,
-naphthoquinonediazide-5-sulfonic acid ester, 2
．． Examples include compounds such as 1-naphthoquinonediazide-4-sulfonic acid ester, 2.1-naphthoquinonediazide-5-sulfonic acid ester, and other sulfonic acid esters of quinonediazide derivatives.

The photosensitizer in the present invention can be synthesized by an esterification reaction of a quinonediazide sulfonic acid compound, and is based on the photosensitive polymer J (1) written by Gentabu Nagamatsu and Hideo Inui.
980) can be synthesized according to the conventional method described in Kodansha (Tokyo), etc.

The photosensitizers in the present invention can be used alone, or two or more types can be used in combination. The amount of the photosensitizer to be blended is 1 to 100 parts by weight, preferably 3 to 40 parts by weight, based on 100 parts by weight of the resin.

If the amount is less than 1 part by weight, it will be impossible to form a pattern;
If the amount exceeds 0.00 parts by weight, afterimages tend to remain.

The sensitizer used in the present invention is not particularly limited as long as it is a compound represented by general formula (1).

Specific examples of the compound represented by general formula (1) include the following.

(3) H (4) H H (5) (6) (9) (16) H N5 (10) (11) (20) TI3 (30) (32) (33) C! 13 shiII3 shiI+3 (26) (27) (28) shi1h (34) shi113 (37) The sensitizers in the present invention may be used alone, or two or more types may be used in combination. The blending amount of the sensitizer is 100 parts by weight or less, preferably 2 to 50 parts by weight, based on 100 parts by weight of the resin. If the amount of the additive exceeds 100 parts by weight, the residual film rate will drop significantly and pattern formation will become difficult.

The positive resist composition of the present invention is used after being dissolved in a solvent, and examples of the solvent include acetone, methyl ethyl ketone,
Ketones such as cyclohexanone and cyclopentanone,
Alcohols such as n-propyl alcohol, 1so-propyl alcohol, n-7'yl alcohol, cyclohexanol, ethylene glycol dimethyl ether,
Ethers such as ethylene glycol diethyl ether and dioxane, alcohol ethers such as ethylene glycol dimethyl ether and ethylene glycol monoethyl ether, propyl formate, butyl formate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate , esters such as ethyl butyrate, methyl lactate, ethyl lactate, cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate,
Cellosolve esters such as propyl cellosolve acetate, butyl cellosolve acetate, propylene glycols such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol mono Diethylene glycols such as ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, halogenated hydrocarbons such as trichloroethylene, aromatic hydrocarbons such as toluene and xylene, dimethylacetamide,
Examples include polar solvents such as dimethylformamide and N-methylacetamide. These may be used alone or in combination of two or more.

The positive resist composition of the present invention may contain compatible additives such as surfactants, storage stabilizers, sensitizers, anti-striation agents, plasticizers, and antihalation agents, as necessary. I can do it.

As the developer for the positive resist composition of the present invention, an alkaline aqueous solution is used. Specifically, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, propylamine, etc. Primary amines, tertiary amines such as diethylamine and dipropylamine, tertiary amines such as trimethylamine and triethylamine, alcohol amines such as diethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide , trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide, and other quaternary ammonium salts.

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

(Example) The present invention will be described in more detail with reference to Examples below.

Novolac resin 100 obtained by mixing m-cresol and p-cresol at a molar ratio of 4:6, adding formalin to this, and condensing the mixture in a conventional manner using an oxalic acid catalyst.
Part by weight, 75% of 2,3,4.4'-tetrahydroxybenzophenone is 1,2-naphthoquinonediazide-5
- Quinonediazide compound 2 which is an ester of sulfonic acid
8 parts by weight were dissolved in 350 parts by weight 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 using a coater, it was betatized at 100°C for 90 seconds to a thickness of 1.1
A resist film of 7 μm was formed. This wafer was placed in a G-line stepper N5R-1505G6E manufactured by Kon Co., Ltd., NA
= 0.54) and a test reticle. Next, it was heated with a 2.38% aqueous solution of tetramethylammonium hydroxide at 23°C for 1 minute.

A positive pattern was obtained by development using the paddle method.

When the sensitivity was evaluated, it was 120 aJ/c-, and when the film thickness of the pattern was measured with a film thickness meter Alpha Step 200 (manufactured by Tenko Co., Ltd.), it was 1.12 μm.

Implementation ■ Soil Add 1 to 100 parts by weight of resin to the resist solution of Comparative Example 1.
A sensitizer of formula (1) was added at a ratio of 0 parts by weight, followed by IBM filtering with a 0.1 μm Teflon filter to prepare a resist solution.

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

When the patterned wafer was taken out and the sensitivity was evaluated, it was found to be 80a+J/cj, and when observed with an electron microscope, lines and spaces of 0.45 μm were resolved. Measure the film thickness of the pattern using a film thickness meter Alpha Step 200.
When measured, it was 1.13 μm. It was found that the sensitivity was improved compared to the resist of Comparative Example 1.

Furthermore, the wafer on which this pattern was formed was etched using a dry etch lag device DEM-451T (manufactured by Nikkei Anelva Co., Ltd.) at a power of 300 W, a pressure of 0.03 Torr, and a gas c.
p, /H=3/1. When etching was performed at a frequency of 13.56 Ml (z), it was observed that only the areas where there was no pattern were etched.

After coating the resist solution of Example 1 on a silicon wafer with a coater, it was plated at 90°C for 90 seconds, and a thickness of 1
．． A resist film of 17 μm was formed.

This wafer is transferred to a G-line stepper NSR-1505G6B.
Exposure was performed using a test reticle. Next, this wafer is subjected to PE B (POST) at 110°C for 60 seconds.
EXPOSURE BAKING) 2.3
2 with 8% tetramethylammonium hydroxide aqueous solution
A positive pattern was obtained by developing at 3°C for 1 minute using the paddle method.

When the patterned wafer was taken out and the sensitivity was evaluated, it was 70 mJ/cd, and when observed with an electron microscope, lines and spaces of 0.40 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was found to be 1.14 μm.

3 to 7 and 6 2 M-cresol, p-cresol, and 3.5-xylenol were mixed at a molar ratio of 50:20:30, formalin was added to this, and condensation was performed using an oxalic acid catalyst in a conventional manner. 100 parts by weight of the obtained novolak resin, 2, 3, 4.
95% of 4'-tetrahydroxyhensephenone is 1
．． 28 parts by weight of a quinonediazide compound, which is an ester of 2-naphthoquinonediazide-5-sulfonic acid, and 5 parts by weight of the sensitizer shown in Table 1 were dissolved in 360 parts by weight of ethyl lactate.
A resist solution was prepared by filtering through a 118m Teflon filter.

After applying the above resist solution onto a silicon wafer with a coater, it was betatized at 90°C for 90 seconds to a thickness of 1.17 μm.
A resist film of m was formed. This wafer was exposed using a g-line stepper NSR-1505G6E and a test reticle. Next, this wafer was heated at 110°C for 60°C.
After performing PEB for seconds, development was performed using a 2.38% tetramethylammonium hydroxide aqueous solution at 23°C for 1 minute using the paddle method to obtain a positive pattern.

Table 1 shows the results of evaluation after taking out the patterned wafer.

Implementation ±1 Novolak resin 100 obtained by mixing m-cresol and p-cresol at a molar ratio of 8:2, adding formalin to this, and condensing it using an oxalic acid catalyst in a conventional manner.
Part by weight was dissolved in 400 parts by weight of ethyl cellosolve acetate, and this was dropped into 3000 parts by weight of toluene to precipitate the resin. After filtering the precipitated resin, heat at 60°C.
It was vacuum dried for 30 hours. 100 parts by weight of vacuum-dried resin, 95% of 2.3,4.4'-tetrahydroxybenzophenone was 1.2-naphthoquinonediazide-5
- Quinonediazide compound 2 which is an ester of sulfonic acid
8 parts by weight and 10 parts by weight of the sensitizer shown in formula (12) were dissolved in 380 parts by weight of ethyl lactate 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 coater, it was baked at 90°C for 90 seconds to a thickness of 1.17 mm.
A resist film of μm thickness was formed. This wafer was exposed using a g-line stepper NSR-1505G6B and a test reticle. Next, this wafer was heated at 110°C for 6
After performing FEB for 0 seconds, development was performed using a 2.38% tetramethylammonium hydroxide aqueous solution at 23° C. for 1 minute using the paddle method to obtain a positive pattern.

When the patterned wafer was taken out and the sensitivity was evaluated, it was 90 mJ/c-, and when observed with 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 1.12 μm.

Novolac resin 100 obtained by mixing m-cresol and p-cresol at a molar ratio of 7=3, adding formalin to this, and condensing it using an oxalic acid catalyst in a conventional manner.
Parts by weight, Trisphenol PA (manufactured by Mitsui Petrochemicals) 9
35 parts by weight of a quinonediazide compound of which 0% is an ester of 1,2-naphthoquinonediazide-5-sulfonic acid, (
20) Seven parts by weight of the aggravating agent shown in formula 20) were dissolved in 350 parts by weight of ethyl cellosolve acetate, and the solution was filtered through a 0.1 μm Teflon filter to prepare a resist solution.

After applying the above resist solution onto a silicon wafer using a coater, it was betatized at 100°C for 90 seconds to a thickness of 1.1
A resist film of 7 μm was formed. This wafer was transferred to an i-line stepper N5R-1505i6A manufactured by Kon Co., Ltd., NA
= 0.45) and a test reticle. Next, this wafer was subjected to PEB at 110°C for 60 seconds, and then exposed to a 2.38% tetramethylammonium hydroxide aqueous solution at 23°C for 1 minute.

A positive pattern was obtained by development using the paddle method.

When the patterned wafer was taken out and the sensitivity was evaluated, it was found to be 140 mJ/cd, and when observed with an electron microscope, lines and spaces of 0.40 μm were resolved. Measure the film thickness of the pattern using a film thickness meter Alpha Step 200.
When measured, it was 1.15 μm.

Disaster coal soil ■ Comonomer of vinylphenol and styrene (molar ratio 5:
5) 100 parts by weight, 90% of trisphenol PA (manufactured by Mitsui Petrochemicals) is 1.2-naphthoquinonediazide-5-
Quinonediazide compound 36, which is an ester of sulfonic acid
A resist solution was prepared by dissolving 5 parts by weight of a sensitizer shown in formula (30) in 320 parts by weight of diglyme and filtering the solution through a 0.1 μm Teflon filter.

After applying the above resist solution onto a silicon wafer using a coater, it was betatized for 90 seconds at IoO''c to form a resist film with a thickness of 1.17 μm.This wafer was attached to an i-line stepper N5R-1505i6A and a test reticle. Next, this wafer was exposed at 110
After PEB at °C for 60 seconds, PEB was performed at 23 °C for 11 minutes with 2.38% tetramethylammonium hydroxide aqueous solution.
A positive pattern was obtained by development using the paddle method.

When the patterned wafer was taken out and the sensitivity was evaluated, it was found to be 90 mJ/cd, and when observed with an electron microscope, lines and spaces of 0.50 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was found to be 1.12 μm.

Novolac resin 100 obtained by mixing m-cresol and p-cresol at a molar ratio of 5:5, adding formalin to this, and condensing the mixture using an oxalic acid catalyst in a conventional manner.
Parts by weight, 95% of 2.3.4.4'-tetrahydroxybenzophenone is 1.2-naphthoquinonediazide-5
- Quinonediazide compound 1 which is an ester of sulfonic acid
4 parts by weight, 18 parts by weight of a quinonediazide compound in which 90% of trisphenol PA (manufactured by Mitsui Petrochemicals) is an ester of 1.2 naphthoquinonediazide-4-sulfonic acid, (
24) A resist solution was prepared by dissolving 10 parts by weight of the sensitizer shown in the formula in 380 parts by weight of ethyl lactate and filtering the solution with an O, 1 μm Teflon filter.

After applying the above resist solution onto a silicon wafer using a coater, it was betatized at 100°C for 90 seconds to a thickness of 1.1
A resist film of 7 μm was formed. This wafer was exposed using an i-line stepper NSR-1505i6A and a test reticle. Next, this wafer was subjected to PEB at 110°C for 60 seconds, and then developed with a 2.38% aqueous solution of tetramethylammonium bitroxide at 23°C for 1 minute using the paddle method to obtain a positive pattern.

When the patterned wafer was taken out and the sensitivity was evaluated, it was 120n+J/c+i! When observed with an electron microscope, lines and spaces of 0.40 μm were resolved. The film thickness of the pattern was measured with a film thickness meter Alpha Step 200 and was found to be 1.14 μm.

Table 1 Example 3 Compound of formula (3) 4 (10) 5 (14) 6 (16) 7 (25) Comparative example 2 None 120 1.14 0.45 140 1. 14 0.45 140 1.13 0.45 110 1.14 0.40 100 1.12 0.40 160 1.13 (Effects of the invention) The positive resist composition of the present invention has excellent sensitivity, resolution, and residual film. It has excellent properties such as heat resistance, heat resistance, and storage stability.
Highly useful for microfabrication of um or less.

Claims (1)

[Claims] (1) A positive resist composition comprising an alkali-soluble phenol resin, a quinonediazide sulfonic acid ester photosensitizer, and a compound represented by general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) R_1 to R_6; Same or different, hydrogen, halogen,
Alkyl group or alkoxy group R_7, R_8; same or different, hydrogen, alkyl group or hydroxyalkyl group n = 1, 2, 3 or 4