JPH041651A - Positive type resist composition - Google Patents

Abstract

PURPOSE:To improve various characteristics, such as sensitivity, resolution, residual film rate, heat resistance, and preservable stability by adding a specific compd. in addition to a novolak resin and quinone diazide compd. to the above compsn. CONSTITUTION:An alkaline-soluble phenolic resin, a photosensitive agent of a quinonediazide sulfonate system, and the sensitizer expressed by formula I are incorporated into this compsn. In the formula I, A denotes an alkylene group, substd. alkylene group, alkenylene group or substd. alkenylene group; R1 to R6 denote hydrogen, halogen, 1 to 4C alkyl group, 1 to 4C alkoxy group or hydroxyl group. The high-sensitivity positive type resist compsn. which excels in the various characteristics, such as sensitivity, resolution, residual film rate, heat resistance, and preservable stability and is suitable for fine working particularly for <=1mum is obtd. in this way.

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 novolank 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. 1983-The difference in solubility between exposed areas disappears, resulting in a decrease in residual film rate and deterioration of resolution, and due to the plasticizing effect of the novolac resin by the sensitizer. Problems such as a decrease in heat resistance arise.

(Problem B 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,
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 the following general formula (1).

(A: alkylene group, substituted alkylene group, alkenylene group, or substituted alkenylene group R1 to Rh: hydrogen, halogen, 01 to C4 alkyl group, C8 to C4 alkoxy group, or hydroxyl group, and may be the same or different) Examples of the alkali-soluble phenolic resin used in the present invention include condensation reaction products of phenols and aldehydes, condensation reaction products of phenols and ketones, vinylphenol polymers, and isopropenylphenol polymers. Examples include polymers, hydrogenation reaction products of these phenolic resins, and the like.

Here, specific examples of phenols used include phenol, cresol, xylenol, ethylphenol,
-valent phenols such as propylphenol, butylphenol, phenylphenol, resorcinol,
Pyrocatechol, hydroquinone, bisphenol A,
Examples include polyhydric phenols such as pyrogallol.

Further, specific examples of aldehydes include formaldehyde, acetaldehyde, benzaldehyde, and terephthalaldehyde.

Furthermore, 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 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 acid 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.

These phenolic resin hydrogenation reaction products can be prepared by any known method, such as by dissolving the phenolic resin in an organic solvent and in the presence of a homogeneous or heterogeneous hydrogenation catalyst. can be prepared by introducing hydrogen.

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

The positive resist composition of the present invention may contain, for example, a copolymer of styrene and acrylic acid, methacrylic acid, or maleic anhydride in order to improve resolution, storage stability, heat resistance, etc., as necessary. Copolymers, copolymers of alkenes and maleic anhydride, vinyl alcohol polymers, vinyl pyrrolidone polymers, rosin shellac, etc. can be added. The amount added is 100% of the above alkali-soluble phenolic resin.
The amount is 0 to 50 parts by weight, preferably 5 to 20 parts by weight.

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
, 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 compound represented by general formula (1) in the present invention is a sensitizer, and its type is not particularly limited.

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

H2 H H n CH2 C o”　XN　′ゞ0 H . ,c, ,,c,.

H ■ (CHz)3 CO□ (CH2)3 CC O″″ゝN″″′0 (CH2)3 og (CH2) 3 The sensitizer in the present invention can be used alone, but two or more types can be used in combination. It may also be used as 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, cyclopentanone, cyclohexanol, n-propyl alcohol, 1s
Alcohols such as o-propyl alcohol and n-butyl alcohol, ethylene glycol dimethyl ether,
Ethers such as ethylene glycol diethyl ether and dioxane, alcohol ethers such as ethylene glycol monomethyl 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 probyl cellosolve acetate and butyl cellosolve acetate, propylene glycols such as propylene glycol, propylene glycol 7-methyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol motubutyl ether, diethylene glycol monomethyl Ether, diethylene glycols such as diethylene glycol monoethyl 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 a surfactant, a storage stabilizer, a sensitizer, a striation inhibitor, a plasticizer, and a halesis inhibitor, if necessary. can.

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. Note that parts and percentages in the examples are based on weight unless otherwise specified.

Novolak 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.
28 parts of a quinonediazide compound in which 75% of 2,3,4.4'-tetrahydroxybenzophenone is an ester of 1,2-naphthoquinonediazide-5-sulfonic acid are dissolved in 350 parts of ethyl cellosolve acetate to obtain 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 coater, it was baked 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 a G-line stepper N5R-1505G6E manufactured by Kon Co., Ltd., NA-
0,54) and a test reticle.

Next, a positive pattern was obtained by developing with a 2.38% aqueous tetramethylammonium hydroxide solution at 23° C. for 11 minutes using the paddle method.

The sensitivity was evaluated as 1201IJ/Cll1ffi, and the film thickness of the pattern was measured using a film thickness meter Alpha Step 200 (
It was 1.12 μm when measured with a Tenko Co., Ltd.).

The sensitizer of formula (1) was added to the resist solution of Comparative Example 1 at a ratio of 10 parts per 100 parts of resin, and dissolved to give 0.1
A resist solution was prepared by filtration with a μm Teflon filter.

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 80 mJ/cm'', and when observed with an electron microscope, lines and spaces of 0.45 μm were resolved. Total alpha step 20
When measured at zero, it was 1.13 μm. It was found that the sensitivity was improved compared to the resist of Comparative Example 1.

Furthermore, the wafer with this pattern formed thereon was subjected to dry etching 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, a gas of CF4/H=3/1, and a frequency of 13.56 MHz.
When etching was performed, it was observed that only the areas where there was no pattern were etched.

Implementation Group I The resist solution of Example 1 was coated on a silicon wafer using a coater, and then betatized at 90°C for 90 seconds to form a layer with a thickness of 1.
．． A resist film of 17 μm was formed.

This wafer is transferred to a G-line stepper N5R-1505G6E.
Exposure was performed using a test reticle. Next, this wafer was subjected to PEB (POST E
XPOSURE BAKING) 2.38%
23℃ with tetramethylammonium hydroxide aqueous solution
A positive pattern was obtained by developing for 1 minute using the paddle method.

When the patterned wafer was taken out and the sensitivity was evaluated, it was 70 taJ/cm'', and when observed with an electron microscope, lines and spaces of 0.40 μm were resolved. Total Alpha Step 2
When measured at 00, it was 1.14 μm.

Mix m-cresol, P-cresol, and 3,5-xylenol in a molar ratio of 50:20 = 30, add formalin to this, and condense using an oxalic acid catalyst by a conventional method. 100 parts of the obtained novolac resin, 2.3.4.4' -
28 parts of a quinonediazide compound in which 95% of tetrahydroxybenzophenone is an ester of 1.2-naphthoquinonediazide-5-sulfonic acid and 5 parts of the sensitizer shown in Table 1 were dissolved in 360 parts of ethyl lactate 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 coater, it was baked 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 N5R-1505G6E and a test reticle. Next, this wafer was heated at 110°C for 60°C.
After performing PEB for seconds, the film was developed with a 2.38% aqueous tetramethylammonium hydroxide solution at 23°C for 11 minutes using the paddle method to obtain a positive pattern.

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

Example Example 3 〃 4 〃 5 〃 6 Sensitizer sensitivity Residual film thickness Resolution axis J/cva2) Cμm) Com) (2)
Compound (3) (8) 00) 1.12 1.13 1.14 1.14 0.45 0.45 0.45 0.50 m-cresol and p-cresol in a molar ratio of 8 Novolak resin 100 obtained by mixing at a ratio of 2, adding formalin to this, and condensing it using an oxalic acid catalyst in a conventional manner.
1 part was dissolved in 400 parts of ethyl cellosolve acetate, and this was dropped into 3000 parts of toluene to precipitate the resin. After the precipitated resin was filtered off, it was vacuum dried at 60°C for 30 hours. 100 parts of vacuum-dried resin, 2, 3, 4
．． 95% of 4'-tetrahydroxybenzophenone is 1
, 28 parts of a quinonediazide compound, which is an ester of 2-naphthoquinonediazide-5-sulfonic acid, and 15 parts of the sensitizer shown by formula (1) were dissolved in 380 parts of ethyl lactate to give a 0.1μ
A resist solution was prepared by filtering through a 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 cm.
A resist film of μm thickness was formed. This wafer was exposed using an i-line stepper N5R-1505i6A and a test reticle. Next, this wafer was heated at 110°C for 6
After performing PEB for 0 seconds, development was performed using a 2.38% aqueous tetramethylammonium hydroxide solution at 23° C. for 11 minutes using the paddle method to obtain a positive pattern.

When the patterned wafer was taken out and the sensitivity was evaluated, it was 90 J/cta! 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 20.
When measured at zero, it was 1.12 μm.

(Effects of the Invention) The resist composition of the present invention has excellent properties such as sensitivity, resolution, residual film rate, heat resistance, and storage stability, and is therefore particularly suitable for microfabrication of 1 μm or less.

Claims (1)

[Claims] (1) Alkali-soluble phenol resin, quinonediazide sulfonic acid ester photosensitizer and the following general formula (I)
A positive resist composition comprising a compound represented by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (A: alkylene group, substituted alkylene group, alkenylene group, or substituted alkenylene group R_1 to R_6: hydrogen, halogen, alkyl group of C_1 to C_4, alkoxy of C_1 to C_4 group or hydroxyl group, which may be the same or different)