JPH03251845A - Positive type photoresist composition - Google Patents

Abstract

PURPOSE:To enhance sensitivity of the composition, as well as resolution, that resistance, and density by incorporating a beta-trione compound. CONSTITUTION:The composition contains a novolak resin, a quinone-diazido compound, and the beta-trione compound represented by formula I in which R is an alkyl or aralkyl compound and X is one of groups represented by formula II, and this trione compound has one carbon atom having 3 carbonyl groups.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a positive photoresist composition, and more specifically, a positive photoresist composition that is sensitive to radiation such as ultraviolet rays, far ultraviolet rays, X-rays, electron beams, and molecular beams. In particular, the present invention relates to a positive photoresist suitable as a resist for manufacturing highly integrated circuits.

[Prior art] As a positive photoresist composition, naphthoquinone-1,2- of polyhydroxybenzophenone is used as a photosensitizer.
Diazide-5-sulfonic acid esters containing novolak made from cresol as a resin component are known.

As integrated circuits become more highly integrated, they have excellent resolution and sensitivity.
Although there is a demand for a positive photoresist with good heat resistance, the current situation is that no product has yet been obtained that satisfies all the performance requirements.

[Problems to be Solved by the Invention] An object of the present invention is to provide a positive photoresist that eliminates the various drawbacks of the prior art, has excellent resolution, sensitivity, and heat resistance, and is suitable as a resist for manufacturing high-density integrated circuits. An object of the present invention is to provide a composition. In particular, it is an object of the present invention to provide a positive photoresist composition with excellent sensitivity without impairing resolution or heat resistance.

[Means for Solving the Problems] The objects of the present invention are achieved by a positive photoresist composition characterized by containing a novolak resin, a quinonediazide compound, and a ρ-trione compound.

As the novolak resin used in the present invention, any known ones used in this field can be used. Specific examples of phenols used as raw materials for novolac resins include phenol, cresol, xylenol, ethylphenol, trimethylphenol, propylphenol, butylphenol, dihydroxybenzene, and naphthols.

As the phenols, it is preferable to use cresols. Particularly preferred is a mixture of m-cresol and p-cresol in a molar ratio of 20/80 to 80/20.

In the present invention, examples of aldehydes to be subjected to an addition reaction with phenols include formalin, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, and benzaldehyde, with formalin and paraformaldehyde being particularly preferred.

Examples of acid catalysts used in the reaction include inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, and perchloric acid, and organic acids such as oxalic acid, formic acid, acetic acid, trifluoroacetic acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid. It will be done.

Although novolak can be produced without a solvent, it can also be produced in the presence of an organic solvent to increase the reaction rate. Organic solvents used at this time include alcohols such as methanol, ethanol, propatool, and butanol;
Cellosolves such as ethyl cellosolve, methyl cellosolve and butyl cellosolve, cellosolve esters such as methyl cellosolve acetate, ethyl cellosolve acetate and butyl cellosolve acetate, aprotic polar solvents such as N-methylpyrrolidone and dimethyl sulfoxide, ethyl acetate, acetic acid Esters such as propyl and butyl acetate, and ethers such as tetrahydrofuran and dioxane are preferred.

The novolac used in the present invention preferably has a dimer content of 10% by weight or less.

By reducing the content of dimer, a resist with good heat resistance and less scum can be obtained.

Such a novolac having a low dimer content can be obtained, for example, by the following method.

(1) A method of extracting novolak powder using a poor solvent.

Novolak is finely ground and stirred in a solvent such as benzene, toluene, xylene, chlorobenzene and dichlorobenzene to extract the low molecular weight portion.

(2) A method in which novolac is dissolved in a good solvent and poured into a poor solvent to reprecipitate it.

Novolac is dissolved in methanol, ethanol, acetone, methyl ethyl ketone, etc., and poured into water or water containing the above organic solvent, and the precipitated polymer is taken out in a furnace and dried.

(3) A method of dissolving novolak in a good solvent and adding a poor solvent to separate it.

Novolac is dissolved in methanol, ethanol, acetone, methyl ethyl ketone, etc., and a poor solvent such as water, petroleum benzine, petroleum ether, ligroin, n-hexane, etc. is added while stirring to precipitate the high molecular weight portion. After removing the supernatant, the polymer is taken out and dried.

In addition to the above method of removing low molecular weight components using a solvent, a method of thin film distillation under high vacuum can also be adopted.

In order to reduce the dimer content to 10% by weight or less, it is preferable to remove 50 to 2%, preferably 30 to 5%, of the low molecular weight components in the novolac.

This allows the monomer content to be 2% by weight or less.

A quinonediazide compound is used as a photosensitizer component in the present invention. The quinonediazide compound can be obtained by a known method, for example, by reacting naphthoquinonediazide sulfonic acid chloride or benzoquinonediazide sulfonic acid chloride with a compound having a hydroxyl group in the presence of a base.

Here, examples of compounds having a hydroxyl group include hydroquinone, resorcinol, phloroglycin, 2,4-dihydroxybenzophenone, 4.4'-dihydroxybenzophenone, 2.4'-dihydroxybenzophenone, 2.
, 3.4-1 lyhydroxybenzophenone, 2.3.4
．． 4'-tetrahydroxybenzophenone, 2. 4
．． 2', 4'-tetrahydroxybenzophenone, 2,3.4.3'-tetrahydroxybenzophenone, 2.3,4.2'-tetrahydroxybenzophenone, 2.3.4.2'4'-pentahydroxybenzophenone , 2,3°4.3', 5'-pentahydroxybenzophenone, 2. 3. 4. 3'
, 4', 5'-hexahydroxybenzophenone, gallic acid alkyl ester, 4,4'-dihydroxybiphenyl, 2,4-dihydroxybiphenyl, bisphenol A1 and bisphenol S, etc., but a low molecular weight novolak should be used. You can also do it.

Among these photosensitizers, trihydroxybenzophenone, tetrahydroxybenzophenone, pentahydroxybenzophenone, and hexahydroxybenzophenone each have an average of 75% or more of hydroxyl groups in their molecules, naphthoquinone-1,2-diazide-5-sulfonic acid, or naphthoquinone-1,2-diazide-5-sulfonic acid. Particular preference is given to compounds esterified with 1,2 diazido-4-sulfonic acid.

The β-trione compound used in the present invention is 1
It means a compound having a structure in which three carbonyl atoms are bonded to one carbon atom.

Examples of the β-trione compound preferably used in the present invention include compounds represented by the following general formula.

Ha (wherein, X is -(CH2) 2 , -(CH2)
3, and R represents an alkyl group or an aralkyl group. ) The alkyl group in the formula is preferably a lower alkyl group,
Hydroxyl group, halogen, lower alkoxy, nitro, cyano,
It may be substituted with lower alkoxycarbonyl, carbamoyl, lower alkylcarbonyl, or the like. Particularly preferred are methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl.

The aralkyl group preferably has the following structure.

CH2A r, -(CH2)2 Ar.

(CH2) 3 A r, (CH2) a A
As rAr, hydroxyl group, halogen, lower alcohol,
Nitro, cyano, lower alkyl carbonyl.

Indicates phenyl and naphthyl which may be substituted with carbamoyl or lower alkylcarbonyl.

In particular, phenyl and naphthyl having 1 to 3 hydroxyl groups are preferably used.

As specific examples of the β-trione compound that can be used in the present invention, the following are particularly preferred.

Although the amount of the β-trione compound in the solid content of the resist is not particularly limited, it has a remarkable effect of improving sensitivity.
In order to obtain good heat resistance, the content is preferably in the range of 3 to 30% by weight. More preferably 5 to 15% by weight
It is.

The above novolak resin, photosensitizer and β-trione compound are dissolved in a suitable organic solvent to form a positive photoresist.

The blending ratio of photosensitizer and other ingredients is 10/90 to 10/90 by weight.
50150, more preferably 15
/85 to 30/70. If the amount of photosensitizer is too small, the sensitivity will be high but the heat resistance will be insufficient; if it is too large, the heat resistance will be high but the sensitivity will be low.

In addition to these components, a surfactant to prevent uneven coating during coating, a dye to prevent reflection of light from the substrate, a sensitizer, etc. can be added as appropriate.

The solvent to be used is not particularly limited as long as it dissolves the novolak, photosensitizer, and other components, but glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, methyl cellosolve acetate, and ethyl cellosolve acetate are used. Cellosolve esters such as tart, propylene glycol monoether acetates such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, monohydroxycarboxylic acids such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate. Esters, aromatic hydrocarbons such as toluene, xylene and chlorobenzene, ketones such as methyl isobutyl ketone, methyl isoamyl ketone and cyclohexanone, or ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, t-butyl acetate, ethylpropylene Mention may be made of esters such as propionate, propylpropionate, isopropylpropionate, butylpropionate, isobutylpropionate, t-butylpropionate and pentylpropionate. In addition, as necessary, ethers such as anisole, benzyl ethyl ether and dihexyl ether, diethylene glycol ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, alcohols such as 1-octatool, 1-nonanol and benzyl alcohol, and benzyl acetate. , esters such as ethyl benzoate, diethyl oxalate, diethyl maleate, diethyl fumarate, γ-butyrolactone, diethyl carbonate, ethylene carbonate, propylene carbonate, aprotic polarity such as dimethylformamide, N-methylpyrrolidone, and dimethylsulfoxide. A solvent etc. can be added.

When using the positive photoresist according to the present invention to create a fine pattern, it is preferable to heat the substrate after exposure and before development (post-exposure bake), thereby making it possible to obtain a pattern with good contrast and less scum. .

The heating method is not particularly limited, and examples thereof include methods using an oven, a hot plate, and the like. The temperature is preferably in the range of 90 to 140°C, more preferably 1
00-130°C. The heating time is in the range of 1 to 60 minutes, preferably 5 to 30 minutes in the case of a circulating oven, and 0.5 minutes in the case of using a hot plate. A suitable time is 5 to 5 minutes, preferably 0.7 to 2 minutes.

[Effects of the Invention] Since the present invention contains a β-trione compound as described above, the sensitivity of the positive photoresist composition can be greatly increased. Therefore, according to the present invention, it is possible to easily and reliably obtain a positive photoresist composition that has excellent resolution, sensitivity, and heat resistance and is suitable as a resist for manufacturing high-density integrated circuits.

[Examples] The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto.

Note that the content of dimer in the present invention is determined from a chromatogram measured by gel permeation chromatography (GPC). Furthermore, in the following explanation, "parts" is an abbreviation for parts by weight.

Synthesis Example 1 A novolak resin was obtained from 35 parts of m-cresol, 65 parts of p-cresol, 0.5 part of oxalic acid, and 46 parts of 37% formalin in a conventional manner.

One part of this novolak was dissolved in 5.00 parts of methanol, and 4.00 parts of water was added dropwise while stirring to precipitate the novolak. The supernatant liquid was removed, and the precipitated novolak was taken out and vacuum-dried at 50° C. for 24 hours. 0.86 parts of novolak was obtained, the weight average molecular weight of this novolak was 7.
, 259, number average molecular weight is 1,745, molecular weight distribution is 4
．． 16, the die weight was 6.1% by weight.

Example 1 18.98 parts of the obtained novolac, 3-(3'4'-
dihydroxyhydrocinnamoyl)-6methyl-1,2
~1.82 parts of pyran-2,4(3H)-dione (formula 12 above), 2,3°4.4'-tetrahydroxybenzophenone on average converted to naphthoquinone-1,2-diazide-5- 5.20 parts of photosensitizer esterified with 3.8 molar equivalents of sulfonic acid, "Troysol" 366
(Surfactant manufactured by TOROY CHEMICAL) 0
．． A resist solution was prepared by dissolving 0.05 parts in 74.0 parts of ethyl cellosolve acetate.

This resist solution was filtered through a 0.2 μm membrane filter.
The resultant was filtered and spin-coated onto a 6-inch silicon wafer using a spinner, and then prebaked on a hot plate at 90° C. for 1 minute to obtain a resist film with a thickness of 1.16 μm.

Next, a g-line stepper (Nippon Kogaku N5RI 505
After exposing the test pattern using G6E, NA=0.54), a post-exposure bake was performed on a hot plate for 1 minute at 110'C.

Paddle development was performed at 23°C for 1 minute using a 2.38% aqueous solution of tetramethylammonium hydroxide, washed with water, and then spin-dried.

When the obtained resist pattern was evaluated using a scanning electron microscope, it was found that 0.5 μm line and space was
The exposure amount for resolving to =1 was 163 mJ/cm2. The residual film rate measured from the difference in film thickness before and after development was 99.
．． It was 7%. Furthermore, the highest temperature (heat resistance) at which a 3 μm pattern did not become round after heat treatment on a hot plate for 5 minutes was 135°C.

Examples 2 to 6, Comparative Example 1 Resist composition solutions were prepared in the same manner as in Example 1, except that the compositions and conditions shown in Table 1 were employed, and evaluated in the same manner. The results are shown in Table 1.

Claims (1)

[Claims] 1. Novolac resin, quinonediazide compound and β-
A positive photoresist composition containing a trione compound. 2. The positive photoresist composition according to claim 1, wherein the β-trione compound is represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X is -(CH_2)_2-, -(CH_2)_
3-▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, -CH_2-O-, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ , and R represents an alkyl group or an aralkyl group. )