JPS60176034A - Positive type photosensitive resin composition - Google Patents

Abstract

PURPOSE:To increase the sensitivity and heat resistance of the titled composition and the rate of a residual film of the composition by preparing the composition from alkaline novolak resin obtd. by condensing m-cresol and xylenol with aldehyde and a 1,2-quinonediazido compound. CONSTITUTION:A positive type photosensitive resin composition is prepd. by dissolving alkaline novolak resin obtd. by condensing m-cresol and xylenol with aldehyde and a 1,2-quinonediazido compound in a solvent such as glycol ether or cellosolve ester. The amount of the 1,2-quinonediazido compound contained is 5- 100pts.wt. per 100pts.wt. alkaline novolak resin. In order to increase the adhesive strength of a coated film of the positive type photosensitive resin composition to a substrate such as a silicon oxide film, chloromethylsilane is applied to the substrate beforehand.

Description

[Detailed description of the invention] The present invention relates to a positive photosensitive resin composition.

Conventionally, as a photoresist for producing integrated circuits, a negative photoresist in which a bisazide compound is blended with cyclized isoprene rubber is known. However, this negative type photoresist has a limitation in resolution, and therefore has the disadvantage that it cannot sufficiently respond to higher integration of integrated circuits. On the other hand, since positive photoresists have superior resolution compared to negative photoresists, they are expected to be able to sufficiently respond to higher integration of integrated circuits.

Most of the positive photoresists currently used for the production of integrated circuits are made by adding a 1,2-quino>diazide compound to an alkali-soluble novolac resin to reduce its solubility in an alkaline aqueous developer solution. 1, 2
This method takes advantage of the property of a monoquinone diazide compound that reacts with light and becomes alkali-soluble. This novolak resin-based positive photoresist has lower sensitivity than the cyclized rubber-based negative photoresist because it has to contain a large amount of 1,2-quinonediazide compound.

In order to improve the sensitivity of novolac-based positive photoresists, lowering the amount of 1,2-quinonediazide compound increases the solubility of the resist coating in an alkaline aqueous solution before exposure, allowing exposure through a photomask. It appears that the developability after this process has improved and the sensitivity has increased. However, since the amount of the 1,2-quinonediazide compound added is small, the unexposed portions that should remain as a resist pattern, but not the exposed portions, are somewhat dissolved, resulting in a decrease in the height of the pattern. The ratio of the height before exposure and after development of the unexposed portion that should remain as a resist pattern is called the residual film ratio, and conventional novolak resin-based positive photoresists have a low film residual ratio. When a novolac resin-based positive photoresist with a low residual film rate is applied to a substrate with a step structure on the surface, exposed to light, and developed to form a resist pattern, the step portions cannot be sufficiently covered by the resist pattern. It is difficult to produce integrated circuits.

Furthermore, in the etching process after resist pattern formation in the integrated circuit manufacturing process, when a wet etching method is used that uses hydrofluoric acid, nitric acid, phosphoric acid, etc. as an etchant, it is difficult to etch only the thickness direction of the substrate. , side etching or under-etching cannot be avoided at the same time, so there is a drawback that resolution cannot be increased. In order to solve this drawback in terms of process, it is preferable to adopt a dry etching method in which halogenated hydrocarbon or the like is turned into plasma and used as an etchant.

However, according to this method, reactive ions such as fluorine ions and chlorine ions attack the resist pattern, so if the dry etching resistance of the resist is poor, the temperature of the substrate will increase, and the resist pattern will be damaged. The pattern is severely damaged, the processing accuracy of the substrate deteriorates, and the yield rate of integrated circuit production deteriorates. Novolac resin-based positive photoresists are said to have better dry etching resistance than other resists, but conventional novolac resin-based photoresists have not reached a fully satisfactory level. As a result of intensive research in order to improve these drawbacks, they discovered that the above-mentioned drawbacks can be overcome by blending a 1,2-quinonediazide compound with a specific alkali-soluble novolac resin, and have arrived at the present invention.

In other words, the gist of the present invention is to provide a positive photosensitive resin composition comprising an alkali-soluble novolac resin and a 1,2-quinonediazide compound, in which the alkali-soluble novolak resin combines m-cresol and xylenol with aldehydes. A positive photosensitive resin composition characterized by being a novolac resin condensed with

The alkali-soluble novolac resin used in the present invention is
It is a novolak resin made by condensing m-cresol and xylenol using aldehydes. The xylenol mentioned above includes 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,
Examples include 4-xylenol and 3.5-xylenol.

In order to better exhibit the effects of the present invention, the alkali-soluble novolac resin has a m-cresol/xylenol monomer composition of 30 to 9515 to 70 (mole ratio).
In particular, a novolac resin condensed with an aldehyde is preferable, with a molar ratio of 50 to 9515 to 50.

In addition, the alkali-soluble novolac resin in the present invention includes a co-condensable monomer 1, such as phenol, 0-
Cresol, ethylphenol, t-butylphenol, 1,4-dihydroxybenzene, 1,3-dihydroxybenzene, trihydroxybenzene, etc. (excluding p-cresol) fc, to the extent that the effects of the present invention are not deviated from. It can also be condensed.

The alkali-soluble novolac resin is synthesized by condensing the monomer with an aldehyde in the presence of an acidic catalyst.

Examples of the aldehydes to be used include formaldehyde, paraformaldehyde, furfural, acetaldehyde, and benzaldehyde, with formaldehyde being preferred.

Examples of the acidic catalyst include inorganic acids such as hydrochloric acid, nitric acid, and W acid;
Organic acids such as formic acid, oxalic acid, acetic acid, etc. can be used.

The amount of the aldehyde used is 0.7 to 3 mol per mol of the predetermined monomer, and the amount of the acidic catalyst used is I X 10 to 5 X 10 per mol of the predetermined monomer.
-3 moles are common. The reaction temperature is usually 70~
It is 130°C.

The 1,2-quinonediazide compound used in the present invention is
Although not particularly limited, examples include 1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-
naphthoquinonediazide-4-sulfonic acid ester, l,
Examples include 2-naphthoquinone diazide-5-sulfonic acid ester. Specifically, p-cresol-
1,2-benzoquinone diazide-4-sulfonic acid ester, resorcin-1,2-1-phthoquino/diazido 4
-1.2 of (poly)hydroxybenzene such as sulfonic acid ester, pyrogallol-1,2-naphthoquinonediazide-5-sulfonic acid ester, phloroglycino-1,2-naphthoquinonediazide-5-sulfonic acid ester
-quinonediazide sulfonic acid esters, 2,4-dihydroxyphenyl-propyl ketone-1,2-benzoquinonediazide-4-sulfonic acid ester, z,4-dihydroxyphenyl-n-hexyl ketone-1,2-1-
7 Toquinone diazido 4-sulfonic acid ester, 2.4
-dihydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3.4-trihydroxyphenyl-n-hexylketone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3
．． 4-17hydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3.4
-) dihydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,4.6-
) (Poly)hydroxyphenylalkyl ketones such as dihydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester and 2,4.6-dolyhydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester or (poly)hydroxyphenylarylketone 1,2-quinonediazide sulfonic acid ester, bis(p-hydroxyphenyl)methane-1,2-naphthoquinonediazide-4-sulfonic acid ester, bis(2,4-dihydroxyphenyl) Methane
1,2-naphthoquinonediazide-5-sulfonic acid ester, bis(2,3,4-trihydroxyphenyl)methane-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,2-bis(p-hydroxyphenyl) ) Propane-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,2-bis(2,4-dihydroxyphenyl)propane-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,2-bis( Bis[(holJ) such as 2,3,4-trihydroxyphenyl)propane-1,2-naphthoquinonediazide-5-sulfonic acid ester
1,2-quinonediazide sulfonic acid esters of hydroxyphenyl coalkane, lauryl-1,2-naphthoquinonediazide-4-sulfonic acid ester of 3,5-dihydroxybenzoate, phenyl-1 2,3,4-trihydroxybenzoate , 2-naphthoquinonediazide-5-sulfonic acid ester, 3.4.5-trihydroxybenzoic acid lau 1 true 1.2-naphthoquinonediazide-5-sulfonic acid triester, 3,4.5-trihydroxybenzoic acid propyl (Poly)hydroxybenzoic acid alkyl ester such as -1,2-naphthoquinonediazide-5-sulfonic acid ester, 3,4.5-)IJ hydroxybenzoic acid phenyl-1,2-naphthoquinonediazide-5-sulfonic acid ester, or 1,2-quinonediazide sulfonic acid esters of (poly)hydroxybenzoic acid alkyl esters, bis(2,5-dihytooxybenzoyl)methane-1,2-naphthoquinone-4-sulfonic esters, bis(2,3, 4-trihydroxybenzoyl)methane-1,2-naphthoquinonediazide-5-sulfonic acid ester, bis(2,4,6-)9hydroxybenzoyl)
Methanol 1,2-naphthoquinonediazide-5-sulfonic acid ester, p-bis(2,5-dihydroxybenzoyl)benzene-1,2-naphthoquinonediazide-4-sulfonic acid ester, p-bis(2,3,4- ) Benzene-1,2-naphthoquinonediazide-5-sulfonic acid ester, p-bis(2,4
,6-dolyhydroxybenzoyl)benzene-1,2-
1,2 of bis[(poly)hydroxybenzoyl]coalkane or bis[(poly)hydroxybenzoyl]benzene such as naphthoquinonediazide-5-sulfonic acid ester
-Quinonediazide sulfonic acid esters, ethylene glycoludi(3,5-dihydroxybenzoate)-1
, 2-naphthoquinonediazide-4-sulfonic acid ester, polyethylene glycoludi(3,5-dihydroxybenzoate)-1,2-naphthoquinonediazide-5-
Sulfonic acid ester, polyethylene glycoluge 1,
4.5-17-hydroxybenzoate)-1,2-naphthoquinonediazide-5-sulfone, 1,2-quinonediazide sulfonic acid esters of (poly)ethylene glycoluge [(poly)hydroxybenzoate] such as acid esters can be mentioned. In addition to these exemplified 1,2-quinonediazide compounds, J. Kosar, “Light”
t-8en, 5itive Systems″339~
352° (1965), John Wiley &
5ons (New York), wS, De,
Written by Forest “pltotoresist” 50
, (1975) IMc Graw-I-1i 11
．． Inc. Mention may also be made of the 1,2-quinonediazide compounds described in , (New York).

The content of these 1,2-quinonediazide compounds is 5 parts by weight based on 100 parts by weight of the alkali-soluble novolac resin.
~100 parts by weight, preferably 10 to 50 parts by weight. If it is less than 5 parts by weight, 1,2
-The insolubilization effect of the quinonediazide compound on the alkali-soluble Novosic resin is insufficient, and it is not possible to differentiate the alkali solubility between the exposed and unexposed areas.
If patterning is difficult and exceeds p, ioo parts by weight,
A short period of light irradiation cannot completely decompose the added 1,2-quinonediazide compound, making development with a developer consisting of an alkaline aqueous solution difficult.

The positive photosensitive resin composition of the present invention is prepared by dissolving the above-mentioned alkali-soluble novolac resin and 1,2-quinonediazide compound in a solvent. Examples of the solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc. Glycol ethers, cellosolve esters such as methyl cellosolve acetate and ethyl cellosolve acetate, aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone and cyclohexanone, and esters such as ethyl acetate and butyl acetate. can. Furthermore, two or more of these solvents may be used in combination. Furthermore, ethers such as benzyl ethyl ether and cyhexyl ether, glycol ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, ketones such as acetonyl acetone and isophorone, fatty acids such as caproic acid and caprylic acid, 1- Octatool, 1-
Alcohols such as nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrosictone, ethylene carbonate,
High boiling point solvents such as esters such as propylene carbonate and phenyl cellosolve acetate may also be added.

Furthermore, if necessary, it is also possible to add surfactants, storage stabilizers, dyes, pigments, etc. to the positive photosensitive resin composition of the present invention.

In addition, in order to improve the adhesive strength between the coating film of the positive photosensitive resin composition of the present invention and a substrate such as a silicon oxide film, hexamethyldisilazane, chloromethylsilane, etc. may be applied to the coated substrate in advance. can.

Examples of the developer for the positive photosensitive resin composition of the present invention include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, trisodium phosphate, and sodium hydrogen phosphate. aqueous solution of n-propylamine, di-n-propylamine, di-n-butylamine, methyldiethylamine,
Virol, 2,5-dimethylpyrrole, β-picoline,
Aqueous solutions of amines such as collidine, piperidine, piperazine, and triethylenediamine, aqueous solutions of alcohol amines such as dimethylethanolamine, triethanolamine, and diethylhydroxylamine, and quaternary ammoniums such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. Examples include aqueous solutions of salts, aqueous ammonia, etc. When producing integrated circuits where the use of developers containing metals becomes a problem, it is preferable to use aqueous solutions of quaternary ammonium salts and cyclic amines. Further, an aqueous solution obtained by adding an appropriate amount of a water-soluble organic solvent such as an alcohol such as methanol or ethanol or a surfactant to the aqueous solution of the alkali mentioned above can also be used as the developer.

The positive photosensitive resin composition of the present invention has high sensitivity, high residual film rate, and high dry etching resistance, and is also excellent in heat resistance and developability. This is obtained by using m-cresol and xylenol.

Generally, in a positive-working photosensitive resin composition, sensitivity and residual film rate have an antinomic relationship, and it is extremely difficult to improve both properties at the same time. However, the positive-working photosensitive resin composition of the present invention , it was possible to simultaneously improve sensitivity and residual film rate.

The positive photosensitive resin composition of the present invention is particularly useful as a positive photoresist for producing integrated circuits;
It is also useful as a positive photoresist for photomask production.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 In a three-way separable flask with an internal volume of 50011 Ll,
- 105 g of cresol and 30 g of 3,5-xylenol
g1: m-cresol/3,5-xylenol-80/
20 (molar ratio)] After the preparation, 92 d of formalin aqueous solution and 0.049 d of oxalic acid were added. While stirring, the separable flask was immersed in an oil bath, and addition condensation polymerization was carried out for 1 hour and 30 minutes while controlling the temperature inside the container at 100°C. After the reaction, increase the temperature of the oil bath to 180℃
At the same time, the pressure inside the reaction vessel was increased to 20 mrx I.
The pressure was reduced to 1F to remove water and unreacted materials. Next, the molten novolac resin (hereinafter abbreviated as novolac resin A) was returned to room temperature and recovered.

Novolac resin Al31I and 2.4.6-)lyhydroxybenzophenone-1,2-naph)quinonediazide-
2 g of 5-sulfonic acid triester (ethyl cellosolve acetate)35. ! After dissolving in i', the pore size is 0.2 μm.
A solution of a positive photosensitive resin composition was prepared by filtration through a membrane filter.

The above solution was applied onto a silicon wafer having a silicon oxide film using a spinner, and then prebaked in an oven at 90'C for 30 minutes to form a 1 μm thick resist film. Next, through a photomask made by Toppan Printing,
Mo manufactured by Qptical Associates, Inc.
Energy calibrated with del 205 UV intensity meter (3
65 nm) was irradiated with 10 mJ/crn2 ultraviolet rays and developed with an aqueous solution of tetramethylgravitanium hydroxyl 12 weight at 20°C for 60 seconds, resulting in a line width of 1.0.
A micrometer pattern could be resolved. Furthermore, when the residual film rate of this resist was measured, it showed a very high value of 94 minutes.

Therefore, it was found that the positive photosensitive resin composition of (1) had high sensitivity and high film remaining rate.

The resist pattern obtained as described above was etched using a parallel plate plasma dry etching device (electrode spacing: 4011).
Attach it to the output ioow.

Carbon tetrafluoride/oxygen (95A
The dry etching resistance of the resist pattern was investigated using plasma. Generally, the ratio of the rate at which a resist pattern is etched to that of a silicon oxide film is called the selectivity ratio, but in this example, the selectivity ratio was as high as 3.0, and the dry etching resistance containing novolac resin was It was confirmed that the properties were excellent.

Examples 2 to 5 A solution of a positive photosensitive resin composition was prepared in the same manner as in Example 1, except that novolac resin A and the 1,2-quinonediazide compound shown in Table 1 were used, and then a resist pattern was formed. As shown in Table 1, all of them were excellent in sensitivity, residual film rate, and dry etching resistance.

Bundle Examples 6 to 8 In place of m-cresol and 3,5-xylenol in the novolac resin A of Example 1, each monomer composition shown in Table 2 was used, and the other additions were made in the same manner as in the case of containing the novolak resin. Using a novolac resin obtained by condensation polymerization, a solution of a positive photosensitive resin composition was prepared in the same manner as in Example 1, and then a resist pattern was formed and its properties were measured. The results are shown in Table 2, and both sensitivity and
It was excellent in film remaining rate and dry etching resistance.

Comparative Example The amount of monomer charged in Example 1 was changed to 113.4 m-cresol.
9, p-cresol 16.29 Cm-cresol/p
-cresol: 87.5/1λ5 (molar ratio)] A novolac resin was synthesized in the same manner as in Example 1 except that the molar ratio was changed to 87.5/1λ5 (molar ratio).

A solution of a positive crab photosensitive resin composition was prepared using this novolak resin in the same manner as in the example, and then a resist pattern was formed.The sensitivity was relatively good at ismJ/α2, but the residual film rate was In some cases, the sensitivity was as low as 80%, and a balance between sensitivity and residual film rate could not be achieved. In addition, the selectivity in the dry etching resistance test was low on Z2, and poor dry etching resistance was obtained.

Claims (1)

[Claims] In a positive photosensitive resin composition comprising an alkali-soluble novolac resin and a 1,2-quinonediazide compound,
A positive photosensitive resin composition, wherein the alkali-soluble novolak resin is a novolak resin obtained by condensing m-cresol and xylenol using an aldehyde.