JPH0990636A - Positive type photoresist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high resolution, high sensitivity and superior heat resistance by using an alkali-soluble resin produced using terpene phenols as starting material and a naphthoquinonediazido compd. SOLUTION: This photoresist compsn. contains an alkali-soluble resin produced using terpene phenols as starting material and a naphthoquinonediazido compd. The alkali-soluble resin is, e.g. terpene phenol novolak resin or terpene phenol resol resin. The terpene phenol novolak resin is produced by bringing a terpene phenol and an aldehyde and/or a ketone into addition condensation in the presence of an acidic catalyst. The aldehyde is, e.g. formaldehyde, p- formaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenyl-acetaldehyde or furfural. The ketone is, e.g. acetone or cyclohexanone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to ultraviolet rays, far ultraviolet rays, X rays.
The present invention relates to a positive photoresist composition for producing an integrated circuit, which has a high sensitivity to rays and electron beams and can be patterned by developing with an aqueous alkaline solution.

[0002]

2. Description of the Related Art Conventionally, a positive type photoresist, which is the mainstream of high resolution type photoresists, has been developed and put into practical use as a composition containing an alkali-soluble novolac resin and a 1,2-naphthoquinonediazide compound as a photosensitive material. That is, the novolak resin is soluble in an alkaline aqueous solution without swelling, and the photosensitive 1,2-naphthoquinonediazide compound itself acts as a dissolution inhibitor of the novolak resin, and the composition as a whole is not alkaline. It is insoluble.

As the 1,2-naphthoquinonediazide compound, 1,2-naphthoquinonediazide sulfonic acid ester is generally used.

When exposed to light, the 1,2-naphthoquinonediazide compound decomposes to form an alkali-soluble substance, and the composition as a whole becomes alkali-soluble. This composition utilizing this specificity for light was particularly useful as a positive resist.

However, as finer pattern rules are demanded as LSIs are highly integrated, photoresists having high resolution and high sensitivity are required. Conventional alkali-soluble novolac resins / 1,2- Compositions composed of naphthoquinonediazide compounds have been unable to satisfy the requirements for high resolution and high sensitivity.

Further, the etching method has been changed from the wet method to the dry method for high integration, but the heat resistance in dry etching (130 to 150 ° C.) is insufficient and the resist pattern is thermally deformed. There is a problem.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positive photoresist composition having high resolution, high sensitivity and excellent heat resistance, focusing on the above problems.

[0008]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors can achieve the above object by using an alkali-soluble resin and a naphthoquinonediazide compound, which are made from terpene phenols as raw materials. We have found this and completed the present invention.

Hereinafter, the present invention will be described in detail. Examples of the alkali-soluble resin containing terpene phenol as a raw material used in the present invention include terpene phenol novolac resin and terpene phenol resole resin, but novolac resin is particularly preferable.

The terpene phenol novolac resin is prepared by addition-condensing terpene phenols and aldehydes and / or ketones in the presence of an acidic catalyst.

Examples of aldehydes and ketones include, but are not limited to, formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, furfural, acetone and cyclohexanone. These aldehydes and ketones may be used alone or in combination of two or more.

In the condensation reaction, terpene phenols may be used in combination with other phenols. The usage ratio of the terpene phenols is at least 5% by weight, preferably 10% by weight or more based on the total amount of the other terpenes. If the proportion of terpene phenols is low, a satisfactory terpene phenol novolac resin cannot be obtained.

Other phenols include phenol,
o-cresol, m-cresol, p-cresol, o
-Ethylphenol, m-ethylphenol, p-ethylphenol, o-butylphenol, m-butylphenol, p-butylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol,
2,6-xylenol, 3,4-xylenol, 3,6
Examples include compounds such as xylenol, p-phenylphenol, p-methoxyphenol, m-methoxyphenol, bisphenol A, bisphenol F, catechol, resorcinol, hydroquinone, and naphthol. These phenols may be used alone or in combination of two or more, but are not limited thereto.

In the condensation reaction, the reaction ratio of terpene phenols and other phenols with aldehydes and ketones depends on the terpene phenols and other phenols.
Aldehydes and ketones are 0.1 to 6 mols, preferably 0.2 to 3 mols per mol, and the reaction is carried out at a temperature of 40 to 200 ° C. for 1 to 12 hours in the presence of an acidic catalyst. If the amount of aldehydes and ketones is too large, the terpene phenol novolac resin has a high molecular weight and the resolution of the photoresist is poor, which is not preferable.

Examples of the acidic catalyst for the condensation reaction include inorganic acids such as hydrochloric acid, nitric acid and sulfuric acid, formic acid, acetic acid, oxalic acid,
Organic acids such as toluene sulfonic acid can be used. The amount of the acidic catalyst used is 0.1 to 5 parts by weight based on 100 parts by weight of the terpene phenols and other phenols. In the condensation reaction, an inert solvent such as aromatic hydrocarbons, alcohols and ethers can be used.

The weight average molecular weight of the novolak resin thus obtained is preferably in the range of 1000 to 20000. If it is less than 1,000, the heat resistance of the photoresist tends to be poor, and if it exceeds 20,000, the resolution tends to be poor, which is not preferable.

The terpene phenols used in the present invention include, for example, 1 phenol compound per 1 molecule of a terpene compound.
Examples thereof include, but are not limited to, a terpene / phenol adduct in which molecules or two molecules are added, or a terpene-phenol copolymer in which a terpene compound and a phenol are copolymerized.

The terpene / phenol adduct can be produced by reacting a terpene compound and a phenol in the presence of an acidic catalyst. Further, the terpene-phenol copolymer can be produced by reacting a terpene compound and a phenol in the presence of a Friedel-Crafts type catalyst. These terpene phenols can be used alone or in combination of two or more.

Examples of the terpene compound as a raw material for producing the terpene phenols used in the present invention include a monocyclic terpene compound, a bicyclic terpene compound and a chain terpene compound. Specific examples thereof include, but are not limited to, the following.

Α-pinene, β-pinene, dipentene, limonene, ferrandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, terpineol, camphene, tricyclene, paramenthene-1, Paramenthene-2, paramenthene-3, paramenthadienes, karen, myrcene, aroocimene, ocimene, dihydromyrcene and the like.

The phenols which are the other raw materials for producing the terpene phenols used in the present invention include phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol and m-. Ethylphenol, p-ethylphenol, o-butylphenol, m-butylphenol, p-butylphenol, 2,3-xylenol, 2,4-xylenol,
2,5-xylenol, 2,6-xylenol, 3,4
Examples include compounds such as -xylenol, 3,6-xylenol, p-phenylphenol, p-methoxyphenol, m-methoxyphenol, bisphenol A, bisphenol F, catechol, resorcinol, hydroquinone, and naphthol. These phenols may be used alone or in combination of two or more,
It is not limited to these.

In the addition reaction of the terpene compound and the phenols, the phenols are used in an amount of 0.3 to 12 mols, preferably 0.5 to 8 mols, per mol of the terpene compound.
It is carried out at a temperature of 20 to 150 ° C. for 1 to 10 hours in the presence of an acidic catalyst. Examples of the acidic catalyst include hydrochloric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, boron trifluoride or its complex, cation exchange resin, activated clay and the like. A reaction solvent may not be used, but a solvent such as an aromatic hydrocarbon, an alcohol, or an ether can also be used.

The terpene / phenol adduct thus produced has a structure in which one molecule or two molecules of the phenol are bonded to one molecule of the terpene compound. Whether one molecule or two molecules of phenols are bonded depends on the type of terpene compound in the reaction, the amount of phenols used, the type of catalyst, and the like. For example, when a terpene compound having one double bond in the molecule is used, a terpene / phenols 1 mol / 1 mol adduct is produced. Further, when a terpene compound having two or more double bonds in the molecule is used, a mixture of terpene / phenol 1 mol / 1 mol adduct and 1 mol / 2 mol adduct or 1 mol / mol
A 2 molar adduct is formed.

Examples of the terpene / phenol 1 mol / 2 mol adduct include compounds represented by the structural formulas shown below in the general formula.

[0025]

Embedded image

In the general formula, R1, R2, R3, R4
Are the same or different and represent a hydrogen atom or a methyl group.

[0027]

Embedded image

In the general formula, R1, R2, R3, R4
Are the same or different and represent a hydrogen atom or a methyl group.

Further, terpene / phenols 1 mol / 1
Examples of the molar adduct include compounds represented by the structural formulas shown below.

[0030]

Embedded image

In the general formula, R1 and R2 are the same or different and each represents a hydrogen atom or a methyl group.

[0032]

Embedded image

In the general formula, R1 and R2 are the same or different and each represents a hydrogen atom or a methyl group.

The copolymerization reaction of a terpene compound and a phenol to produce a terpene-phenolic copolymer is
0.3 to 0.3 of phenols per mol of terpene compound
12 moles, preferably 0.5-6 moles, are used in the presence of a Friedel-Crafts type catalyst at a temperature of 0-120 ° C.
Let it run for 10 hours. Examples of the Friedel-Crafts type catalyst include aluminum chloride, boron trifluoride or a complex thereof. At that time, a reaction solvent such as an aromatic hydrocarbon is generally used. At this time, if the amount of phenols is less than 0.3 mol, the terpene phenol novolac resin is inferior in alkali-solubility, which is not preferable.
No change is observed in the product even if it exceeds the molar amount. The weight average molecular weight of the obtained terpene phenol copolymer is preferably 300 to 2000.

As the alkali-soluble resin used in the present invention, another alkali-soluble resin can be used in combination with the alkali-soluble resin made from terpene phenols as a raw material. Examples of other alkali-soluble resins include novolak resins, polyhydroxystyrene and its derivatives, and acetone pyrogallol resins, but are not limited to these.

As the naphthoquinonediazide compound used as a photosensitive material in the present invention, a naphthoquinonediazide sulfonic acid ester of a polyhydroxy compound can be used. Resorcin as a preferred polyhydroxy compound,
p-cresol, pyrogallol, 2,3,4-trihydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 7-hydroxy-2- (2,4-dihydroxyphenyl) ) -2,4,4-Trimethylchroman, acetone-pyrogallol condensation resin and the like, but not limited thereto. These naphthoquinonediazide compounds are used alone or in combination of two or more.

These naphthoquinone diazide sulfonic acid esters can be obtained by condensing naphthoquinone diazide sulfonic acid chloride with a polyhydroxy compound in the presence of a weak alkali.

The positive-type photoresist composition of the present invention is obtained by combining the alkali-soluble resin obtained from the above-mentioned terpene phenols as a raw material and the naphthoquinonediazide compound. The mixing ratio of the alkali-soluble resin made from terpene phenols and the naphthoquinone diazide compound is 1
5 parts by weight of naphthoquinonediazide compound to 100 parts by weight
To 100 parts by weight, preferably 10 to 50 parts by weight.
When the amount of the naphthoquinonediazide compound is less than 5 parts by weight, the resolution is remarkably lowered, and when it exceeds 100 parts by weight, the sensitivity and the solubility are lowered, which is not preferable.

A surfactant, a stabilizer, a dye, a pigment, a plasticizer, an adhesion aid and the like can be added to the photoresist composition of the present invention, if necessary.

The developer of the positive photoresist composition of the present invention includes sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate,
Inorganic alkalis such as aqueous ammonia, ethylamine, n-
Primary amines such as propylamine, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethyl Quaternary ammonium salts such as ammonium hydroxide and tetraethylammonium hydroxide, pyrrole, piperidine, 1,8-diazabicyclo (5,4,0) -7-undecene, 1,5-
Aqueous solutions of alkalis such as cyclic amines such as diazabicyclo (4,3,0) -5-nonane can be used. Further, an appropriate amount of alcohols and surfactants may be added to the above aqueous solution of alkalis for use.

When the positive photoresist composition of the present invention is applied to a substrate such as a silicon wafer, an alkali-soluble resin containing terpene phenols as a raw material and naphthoquinone diazide sulfonate are dissolved in a solvent and spin-coated. It may be applied with a coater or the like.

As the solvent used at this time, alcohol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, cellosolve esters such as methyl cellosolve acetate and ethyl cellosolve acetate, ketones such as methyl ethyl ketone and cyclohexanone. , Ethers such as dioxane and ethylene glycol diethyl ether, fatty acid esters such as ethyl acetate, butyl acetate, methyl lactate and ethyl lactate, and aromatic hydrocarbons such as toluene and xylene. These solvents can be used alone or as a mixture of several kinds.

The positive photoresist composition thus prepared can be used to form a circuit, for example, by the following treatment. That is, it was filtered with a Teflon filter of 0.2 μm and applied on a silicon wafer treated with disilazane so as to have a film thickness of 1.0 μm, and after drying,
It is exposed using ultraviolet rays or deep ultraviolet rays. Next, heating is performed, development is performed with an alkali developing solution, and further drying is performed to form a positive resist pattern. Finally, a circuit can be formed by etching this resist pattern with oxygen plasma or the like. Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples.

[0044]

【Example】

1) Production Example of Terpene Phenols-a After charging 6 mol of phenol and 34 g of strongly acidic cation exchange resin into a 4-neck flask having an internal volume of 1 liter equipped with a thermometer, a stirrer, a dropping funnel and a cooling tube. , 80
While maintaining the temperature at 0 ° C, 1 mol of α-pinene was added dropwise over 4 hours and then stirred for 2 hours to cause a reaction. Then
The cation exchange resin was removed from the mixed solution by filtration,
The obtained reaction solution is washed twice with distilled water and then 5 mmH
Under a reduced pressure condition of g, the mixture was kept at 250 ° C. for 30 minutes to distill off unreacted substances and by-products to obtain a pale yellow resinous substance. This pale yellow resinous substance was purified by crystallization by a recrystallization method using toluene to obtain 98 g of a white powder. As a result of analyzing this white powder by gas chromatography, it was found that the compound corresponding to the general formula (1) and the compound corresponding to the general formula (2) were contained at 63% by weight and 31% by weight, respectively. Nuclear magnetic resonance spectrum (NM
R), and mass spectrometry (MS) showed that the compound of the general formula (1) was 1,3-bis (4-hydroxy-benzene) -p.
-Menthane, the compound of the general formula (2) is 2,8-bis (4
-Hydroxy-benzene) -p-menthane.

2) Production Example of Terpene Phenols-b to c A terpene di-o-cresol (b) was produced in the same manner as in 1) -a except that o-cresol or catechol was used as a raw material. And 124 g of terpene dicatechol (c) were obtained. Product b: compound of general formula (1) = 54% by weight, compound of general formula (2) = 39% by weight.

3) Production Example of Terpene Phenols-d A four-necked flask equipped with a stirrer, a thermometer, a dropping funnel, and a cooling tube was charged with 94 g of phenol and 34 g of strong acid cation exchange resin, and then 80 1 while heating to ℃
-P-Menten 138g was added dropwise over 4 hours, then 2
The reaction was allowed to stir for a period of time. Next, the cation exchange resin was removed by filtration, the obtained reaction oil was dissolved in 200 g of toluene, and washed with distilled water three times. Further, toluene and unreacted substances are distilled off to obtain 182 g of a white solid terpene / phenol adduct represented by the general formula (3) at a distillation temperature of 130 to 160 ° C. under a vacuum of 5 mmHg. It was

4) Production Example of Terpene Phenols-e Production was conducted in the same manner as in Production Example 3) -d except that 136 g of camphene was used as a terpene compound as a raw material, and terpene / phenol addition represented by the general formula (4) was performed. Body 146
g was obtained.

5) Production Example of Terpene Phenols-f In a four-necked flask equipped with a stirrer, a thermometer, a dropping funnel, and a cooling tube, 94 g of phenol and 230 of toluene were added.
g, 6g of trifluoroboron ether complex, 30 ° C
While stirring at 1, 136 g of limonene was added dropwise for 2 hours, and then for 2 hours. The obtained reaction oil was washed with ion-exchanged water three times, and toluene was distilled off by distillation, and unreacted substances and low-polymerization substances were further distilled off under the conditions of 250 ° C./5 mmHg to give a terpene phenol copolymer (f ) Was obtained. Gel permeation chromatography (G permeation chromatography of the obtained terpene phenol copolymer
The weight average molecular weight of the polystyrene equivalent of PC) is 91.
It was 0.

6) Production Example of Terpene Phenols-g A terpene phenol copolymer (g) was produced in the same manner as in the production example of 5) -g except that the amount of bisphenol A charged as the raw material phenols was 80 g. 185g was obtained. The weight average molecular weight of the obtained terpene phenol copolymer by GPC polystyrene conversion was 860. 7) Production Example of Alkali-Soluble Terpene Phenol Novolac Resin 1 135
g, m-cresol 60 g, p-cresol 90 g, 3
102 g of 7% formalin aqueous solution and 0.4 g of oxalic acid
Place in a separable flask and stir at 100 ℃
The temperature was raised to, and the reaction was carried out for 5 hours. Then vacuum degree 30mmH
The pressure was gradually reduced to g to remove water and unreacted monomers. The temperature is gradually raised to finally 170 ° C / vacuum degree 30.
mmHg. The weight average molecular weight of the obtained terpene phenol novolac resin in terms of polystyrene by GPC was 8,400.

8) Production Example of Alkali-Soluble Terpene Phenol Novolac Resins 2 to 7 m-using -b to -g as terpene phenols
A terpenephenol novolac resin was obtained in the same manner as in 7) above, except that cresol and p-cresol were used as shown in Table 1. The weight average molecular weight of the obtained terpene phenol novolac resin by GPC is shown in Table 1.

[0051]

[Table 1]

Example 1 10 g of an alkali-soluble terpene phenol novolac resin 1 and 2.5 g of 1,2-naphthoquinonediazide-5-sulfonic acid ester of 2,3,4-trihydroxybenzophenone (X) were mixed with ethyl cellosolve acetate. 35
to obtain a positive photoresist composition.

This positive photoresist composition was added to 0.2
It was filtered with a Teflon filter of μm and coated on a silicon wafer treated with hexamethyldisilazane by a spin coater so as to have a dry film thickness of 1.2 μm.
After second drying, it was exposed at 365 nm using a reduction projection exposure device. After the exposure, it was dried at 110 ° C. for 100 seconds, developed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution, further washed with water and dried to obtain a resist pattern.

The resist pattern thus obtained is observed with a scanning electron microscope (SEM) to obtain the resolution,
The heat resistance was represented by a temperature at which a silicon wafer having a resist pattern formed thereon was heated at a constant temperature for 30 minutes and the pattern was not deformed. The sensitivity is defined as the reciprocal of the exposure time required to resolve a 1.0 μm pattern,
It is shown as a relative value with respect to the sensitivity of Comparative Example 1. The results are shown in Table 3.

Examples 2-7 Alkali-soluble terpene phenol novolac resins,
The type and blending amount of 1,2-naphthoquinonediazide-5-sulfonate were set as shown in Table 2, and a positive photoresist composition was prepared and evaluated in the same manner as in Example 1. Table 3 shows the evaluation results.

Comparative Examples 1-2 Novolak resin A consisting of m-xylene / p-xylene = 40 mol% / 60 mol% as an alkali-soluble resin
(Weight average molecular weight = 7,300) was used, and a positive photoresist composition was prepared in the same manner as in Example 1 except that 1,2-naphthoquinonediazide-5-sulfonic acid ester was used as shown in Table 2. evaluated. Table 2 shows the formulation of the photoresist composition and Table 3 shows the evaluation results.

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

[Effect] The positive photoresist composition obtained by the present invention is excellent in resolution, heat resistance and sensitivity, and is suitable for producing an integrated circuit having a high degree of integration.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinobu Mineyama 1080 Takagicho, Fuchu City, Hiroshima Prefecture Yasuhara Chemical Co., Ltd.

Claims (4)

[Claims] 1. A positive photoresist composition containing an alkali-soluble resin made from a terpene phenol as a raw material and a naphthoquinonediazide compound. 2. The composition according to claim 1, wherein the alkali-soluble resin made from a terpene phenol as a raw material is a condensation reaction product of a terpene phenol and an aldehyde and / or a ketone. 3. The terpene phenols are terpene / phenol adducts obtained by adding one molecule or two molecules of phenol to one molecule of a terpene compound.
Or the composition according to 2. 4. The composition according to claim 1 or 2, wherein the terpene phenol is a terpene phenol copolymer obtained by copolymerizing a terpene compound and a phenol.