JPH0654385B2 - Positive type radiation sensitive resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a positive-type radiation-sensitive resin composition, more specifically, a specific alkali-soluble novolac resin and 1,
The present invention relates to a positive radiation-sensitive resin composition containing a 2-quinonediazide compound and suitable as a resist for producing integrated circuits.

(Prior Art) Conventionally, as a resist used for producing an integrated circuit, a negative resist in which a bisazide compound is mixed with a cyclized rubber, and an alkali-soluble novolak resin in 1,2-
A positive resist containing a quinonediazide compound is known. In the negative resist, the bisazide compound desorbs nitrogen to become nitrene by light irradiation, and three-dimensionally crosslinks the cyclized rubber, but the light irradiated portion is not completely cured, so in a developer containing an organic solvent. There is a drawback that the resist pattern swells greatly and the resolution of the resist pattern is poor.

On the other hand, since the positive resist contains an alkali-insoluble 1,2-quinonediazide compound in an alkali-soluble novolac resin, it hardly dissolves in a developer composed of an alkaline aqueous solution, and hardly swells. Therefore, even if the 1,2-quinonediazide compound in the light-irradiated portion is converted to a carboxylic acid and developed with a developer containing an alkaline aqueous solution,
Since the change in solubility is extremely small in the non-irradiated area to be the resist pattern, a resist pattern faithful to the mask pattern and having high resolution can be obtained. Therefore, in recent years, when high integration of integrated circuits is required, such positive resists having excellent resolution are widely used.

Further, attempts to increase the resolution of the resist have been made not only by improving the characteristics of the resist, but also by improving the manufacturing method of the integrated circuit, for example, changing the conventional mainstream wet etching method to dry etching method.

(Problems to be solved by the invention) However, in this dry etching method, since the substrate is etched with reactive ions, the temperature of the substrate rises, the resist pattern is thermally deformed, and the dimensional accuracy is lowered, There is a drawback that highly reactive fluorine ions, chlorine ions, etc. damage the resist pattern.

Conventionally, commercially available novolac resin-based positive resists have been evaluated to be able to withstand this severe dry etching condition as compared with other resists, but at present they are not sufficiently satisfactory.

An object of the present invention is to provide a positive-type radiation-sensitive resin composition in which the dry etching resistance of a novolac resin-based positive resist is improved, and further the resolution and heat resistance are improved.

(Means for Solving Problems) The present invention relates to at least one phenol (A) selected from resorcinol, pyrogallol and phloroglicinol and the following general formula (I): (Wherein R ₁ , R ₂ and R ₃ represent the same or different hydrogen atom or methyl group), and the phenols (B) are represented by a molar ratio of (A) / (B) = 1/99. -10
Provided is a positive-type radiation-sensitive resin composition comprising an alkali-soluble novolak resin obtained by polycondensation with a carbonyl compound, which is used in a ratio of 0/0, and a 1,2-quinonediazide compound. It is a thing.

Examples of the phenols (B) used in the present invention include phenol, o-cresol, m-cresol, p-
Cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-butylphenol,
m-butylphenol, p-butylphenol, 3,5
-Xylenol, 2,4-xylenol, 2,5-xylenol, 3,4-xylenol, 2,3,5-trimethylphenol and the like. Of these, preferred are phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,
Examples include 5-xylenol and 2,3,5-trimethylphenol. These phenols (B) can be used alone or in admixture of two or more.

Usage ratio of phenols (A) and (B) [(A) /
(B)] is 1/99 to 100/0 (molar ratio), preferably 5/95 to 100/0 (molar ratio). 1/99
If it is less than the (molar ratio), the dry etching resistance, resolution and heat resistance of the resist, which is the object of the present invention, are insufficient.

The carbonyl compound used in the present invention is represented by, for example, the following general formula (II).

[Wherein, R ₆ and R ₇ are the same or different and represent a hydrogen atom, or an alkyl group, an aryl group, an alkenyl group or an aralkyl group similar to R ₁ , R ₂ , R ₃ , R ₄ and R ₅ described above. ].

Examples of the carbonyl compound include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, toluylbenzaldehyde, mesitylbenzaldehyde, phenethylbenzaldehyde, o-hydroxybenzaldehyde, m. -Hydroxybenzaldehyde, p-hydroxybenzaldehyde,
o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, m-
Methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn-butylbenzaldehyde, acrolein, crotonaldehyde, cinnamaldehyde, acetone, methylethylketone, diethylketone, methylisobutylketone, methylphenylketone, methylbenzylketone, and the like. Of these compounds, formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, acrolein, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl phenyl ketone, methyl benzyl ketone and the like are preferable.

The carbonyl compound may be used alone or in combination of two or more, and is preferably 0.7 to 3 mol, particularly preferably 0.7 to 2 per 1 mol of the total of the phenols (A) and (B). Used in moles. If it is less than 0.7 mol, the residual amount of unreacted phenols (A) and (B) will be large, so that the softening point of the alkali-soluble novolac resin will be low, and if it exceeds 3 mol, the alkali-soluble novolac resin will gel. .

In the production of the alkali-soluble novolac resin used in the present invention, the phenols (A) and (B) and the carbonyl compound are usually polycondensed using an acid catalyst. Examples of the acid catalyst include inorganic acids such as hydrochloric acid, nitric acid and sulfuric acid, and organic acids such as formic acid, acid and acetic acid. The amount of these acid catalysts used is usually 1 × 10 ^{−7 to} 5 × 10 ⁻¹ mol, preferably 1 × 10 ^{−5 to} 5 × 10 ⁻¹ per 1 mol of the total of phenols (A) and (B). It is a mole. 1 x 10
^If it is less than ^-7 mol, an alkali-soluble novolac resin having a slow reaction and a high softening point cannot be obtained, and if it exceeds 5 x 10 ^-1 mol, the alkali-soluble novolac resin gels.

In the reaction, the reaction medium may not be used, but water or a hydrophilic solvent, or a mixture thereof may be used as the reaction medium. Examples of the hydrophilic solvent used at this time include alcohols such as methanol, ethanol, propanol and butanol, ethers such as tetrahydrofuran, dioxane and diglyme, esters such as ethyl acetate, propyl acetate and butyl acetate, or acetonitrile and propylene. Nitriles such as pionitrile and butyronitrile may be mentioned. The amount of these reaction media used is usually 5000 parts by weight or less, preferably 10 to 10 parts by weight per 100 parts by weight of the total of the phenols (A) and (B).
It is 00 parts by weight. If it exceeds 5000 parts by weight, the reaction becomes slow.

The reaction temperature is appropriately selected according to the reaction raw material, but usually,
The temperature is 10 to 200 ° C, preferably 60 to 160 ° C. If the reaction temperature is lower than 10 ° C, the reaction is slow, and if it exceeds 200 ° C, the alkali-soluble novolac resin gels. The reaction is preferably carried out under pressure in an inert gas, for example, in a closed system filled with nitrogen gas, helium gas, argon gas, etc. Usually, the difference between the internal pressure and the external pressure is 1 to 50 kg / cm ² , and preferably Is 3 to 25 kg / cm ² .

After the reaction, in order to remove the unreacted raw materials, the acid catalyst and the reaction medium existing in the system, the internal temperature is generally set to 130 to
The temperature is raised to 230 ° C., the volatile matter is distilled off under reduced pressure, and then the molten novolac resin is drowned on a steel belt or the like to recover the alkali-soluble novolac resin.

After completion of the reaction, the reaction product is dissolved in the hydrophilic solvent and added to a precipitating agent such as water, n-hexane, petroleum ether, or n-heptane to precipitate a novolak resin, and the precipitate is separated. Alternatively, the alkali-soluble novolak resin can be recovered by a method of heating and drying.

The resin composition of the present invention contains a 1,2-quinonediazide compound. The 1,2-quinonediazide compound is usually used in an amount of 5 to 100 parts by weight, preferably 10 to 5 parts by weight, based on 100 parts by weight of the alkali-soluble novolac resin.
0 parts by weight are used. If it is less than 5 parts by weight, the effect of insolubilizing the 1,2-quinonediazide compound on the alkali-soluble novolac resin is insufficient because the addition amount is small,
It is difficult to form a pattern because it is impossible to make a difference in the solubility between the radiation-irradiated portion and the non-radiation-irradiated portion in a developer containing an alkaline aqueous solution, and it is difficult to form a pattern when it exceeds 100 parts by weight. Since the 2-quinonediazide compound cannot be decomposed and a part of the compound remains, it becomes difficult to develop with a developer containing an alkaline aqueous solution.

Examples of such a 1,2-quinonediazide compound include p-cresol-1,2-benzoquinonediazide-
1,2- (poly) hydroxybenzene such as 4-sulfonic acid ester, resorcinol-1,2-naphthoquinonediazide-4-sulfonic acid ester, pyrogallol-1,2-naphthoquinonediazide-5-sulfonic acid ester
Quinone diazide sulfonic acid esters, 2,4-dihydroxyphenyl-propyl ketone-1,2-benzoquinone diazide-4-sulfonic acid ester, 2,4-dihydroxyphenyl-n-hexyl ketone-1,2-naphthoquinone diazide-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-
Trihydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3,4, -trihydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,4,6-trihydroxybenzophenone -1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,4,6-trihydroxybenzophenone-1,2-naphthoquinonediazide-
5-sulfonic acid ester, 2,2 ', 4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3,4,4'-tetrahydroxybenzophenone-1,2- Naphthoquinonediazide-5-sulfonate, 2,2 ', 3,
4,6'-pentahydroxybenzophenone, 2,3
(Poly) hydroxyphenylalkylketone or (poly) hydroxyphenylarylketone such as 3 ', 4,4', 5'-hexahydroxybenzophenone, 2,2 ', 3,4,4', 6'-hexahydroxybenzophenone 1,2-quinonediazide sulfonic acid esters of
Bis (p-hydroxyphenyl) methane-1,2-naphthoquinonediazide-4-sulfonic acid ester, bis (2,4-dihydroxyphenyl) methane-1,2-naphthoquinonediazide-5-sulfonic acid ester, bis (2,2 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 (2,3) , 4-Trihydroxyphenyl) propane-1,2-naphthoquinonediazide-5-sulfonate, etc. 1,2-quinonediazidesulfonates of bis [(poly) hydroxyphenyl) alkane, 3,5-dihydroxybenzoic acid Lauryl-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3,4-trihydroxybenzoic acid phenyl-1,2-naphthoquinonediazide-5-sulfonic acid ester, 3,4,5-trihydroxybenzoic acid Propyl-
1,2-naphthoquinonediazide-5-sulfonate, phenyl 3,4,5-trihydroxybenzoate-
1,2-Quinonediazide-5-sulfonic acid alkyl esters such as 1,2-naphthoquinonediazide-5-sulfonic acid esters or 1,2-quinonediazidesulfonic acid esters of (poly) hydroxybenzoic acid aryl esters, bis (2,5-dihydroxybenzoyl) ) Methane-1,2-
Naphthoquinonediazide-4-sulfonic acid ester, bis (2,3,4-trihydroxybenzoyl) methane-
1,2-naphthoquinonediazide-5-sulfonic acid ester, bis (2,4,6-trihydroxybenzoyl) methane-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-trihydroxybenzoyl) benzene-1,2-naphthoquinonediazide-5-sulfonic acid ester, p-bis (2 , 4, 6
-Trihydroxybenzoyl) benzene-1,2-naphthoquinonediazide-5-sulfonic acid ester or other bis [(poly) hydroxybenzoyl] alkane or bis [(poly) hydroxybenzoyl] benzene 1,2-
Quinonediazide sulfonates, ethylene glycol-di (3,5-dihydroxybenzoate) -1,
2-naphthoquinonediazide-5-sulfonic acid ester,
Polyethylene glycol-di (3,4,5-trihydroxybenzoate) -1,2-naphthoquinonediazide-
1,2- (Poly) ethylene glycol-di [(poly) hydroxybenzoate] such as 5-sulfonic acid ester
Quinonediazide sulfonates, α-pyrone-based natural dyes having a hydroxy group, 1,2-quinonediazide sulfonates, γ-pyrone-based natural dyes having a hydroxy group, 1,2-quinonediazide sulfonates, hydroxy groups 1,2-quinonediazide sulfonic acid esters of diazine-based natural dyes having

In addition to these 1,2-quinonediazide compounds, J. K
by Osar "Light-Sensitive Sys"
tems "339-352 (1965), John W
iley & Sons (New York) and W.I. S.
"Photoresist" 50 by De Forest
(1975), McGraw-Hill, Inc. ，
The 1,2-quinonediazide compounds listed in (New York) can also be used.

Further, as described in JP-A-58-17112, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,2-naphthoquinonediazide-4-sulfonyl chloride, or 1,2-naphthoquinonediazide-5-sulfonyl chloride is added to the hydroxyl group of the alkali-soluble novolac resin. A resin obtained by condensing 1,2-benzoquinonediazide-4-sulfonyl chloride at an equivalence ratio of 0.001 to 0.5 can also be used as a 1,2-quinonediazide compound.

These 1,2-quinonediazide compounds may be used alone or in admixture of two or more.

When applying the resin composition of the present invention to a substrate such as a silicon wafer, the alkali-soluble novolac resin and the 1,2-quinonediazide compound are dissolved in a solvent, and this is spin-coated, flow-coated, roll-coated or the like. Apply to the substrate.

Examples of the solvent used at this time include ethylene glycol monomethyl ether, glycol ethers such as ethylene glycol monoethyl ether, methyl cellosolve acetate, cellosolve esters such as ethyl cellosolve acetate, methyl ethyl ketone, ketones such as cyclohexanone, or ethyl acetate. , Butyl acetate, methyl lactate, ethyl lactate and the like. These solvents may be used alone or in combination of two or more. Furthermore, for example, aromatic hydrocarbons such as toluene and xylene, ethers such as benzyl ethyl ether and dihexyl ether, glycol ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, ketones such as acetonylacetone and isophorone, and capron. Acids, fatty acids such as caprylic acid, alcohols such as 1-octanol, 1-nonanol and benzyl alcohol, esters such as benzyl acetate, ethyl benzoate, diethyl acid, diethyl maleate, ethylene carbonate, propylene carbonate and phenyl cellosolve acetate It is also possible to add a high-boiling solvent such as compounds or lactones such as γ-butyrolactone and δ-valerolactone.

The resin composition of the present invention may be used in combination with a phenol such as phenol, cresol, ethylphenol, butylphenol, or xylenol, and a novolak resin obtained by condensing a carbonyl compound such as formaldehyde, acetaldehyde or benzaldehyde. .

Further, the resin composition of the present invention may contain a sensitizer in order to improve the sensitivity as a resist. Further, the resin composition of the present invention may contain a surfactant.

Further, the resin composition of the present invention may contain a storage stabilizer, a colorant and the like, if necessary.

The resin composition of the present invention is prepared by dissolving a predetermined amount of an alkali-soluble novolac resin, a 1,2-quinonediazide compound and various compounding agents in a solvent and filtering the solution with a filter having a pore size of about 0.2 μm.

In addition, in order to improve the adhesive force between the coating film of the resin composition of the present invention and the substrate, hexamethyldisilazane, chloromethylsilane or the like can be applied in advance to the substrate to be coated.

As a developer when using the resin composition of the present invention as a positive resist, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, inorganic alkalis such as aqueous ammonia, ethylamine, Primary amines such as n-propylamine, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and methyldiethylamine
Amine, alcohol amines such as dimethylethanolamine and triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide and choline, or pyrrole, piperidine, 1,8-diazabicyclo (5,4,0) -7 An alkaline aqueous solution prepared by dissolving cyclic amines such as undecene and 1,5-diazabicyclo (4,3,0) -5-nonane is used. Further, an aqueous solution prepared by adding an appropriate amount of a water-soluble organic solvent such as methanol, ethanol or acetone or a surfactant to the alkaline aqueous solution can be used as a developer.

Example 1 Example 1 A resorcinol 110 was added to a pressure resistant reactor having an internal volume of 1500 ml.
g, 90% by weight acetaldehyde 54 g, acid 0.3 g
And 73 g of n-butanol were charged, while stirring
The internal temperature was kept at 140 ° C. to carry out polycondensation for 10 hours.
After completion of the reaction, the reaction product was poured into a large amount of water to precipitate the novolac resin. Then, the precipitate is collected and the temperature is 40 ° C.
After vacuum drying for 24 hours, water, unreacted materials and n-butanol were removed to obtain an alkali-soluble novolac resin.

10 g of this alkali-soluble novolac resin and 2.5 g of bis (2,4-dihydroxyphenyl) methane-1,2-naphthoquinonediazide-5-sulfonic acid tetraester were dissolved in 37.5 g of ethyl cellosolve acetate to give a pore size of 0.2 μm. The solution of the resin composition of the present invention was prepared by filtering with a membrane filter of.

The obtained solution was spin-coated on a silicon wafer having a silicon oxide film by a spinner, and then prebaked at 90 ° C. for 2 minutes to form a 1.2 μm thick resist film.

Then, through the resolution test pattern mask, the wavelength 43
After irradiating with an ultraviolet ray having a center of 6 nm, it was developed with a 1 wt% tetramethylammonium hydroxide aqueous solution to form a resist pattern.

As a result, the resist pattern having a line width of 0.9 μm faithfully reproduced the pattern mask and had good resolution. The silicon wafer having this resist pattern was placed on a hot plate for 5 minutes, and the temperature of the hot plate and the thermal deformation state of the resist pattern were observed. When the maximum temperature at which the resist pattern was not deformed was defined as the heat-resistant temperature, the heat-resistant temperature of this product was 170 ° C., indicating extremely good heat resistance.

Further, the obtained resist pattern was mounted on a parallel plate type plasma etching device (electrode interval 40 mm) and output 1
The dry etching resistance of the resist pattern was examined under the conditions of 00 W and a gas pressure of 15 pa of tetrafluoromethane / oxygen [95/5 (volume ratio)]. The selection ratio of this resist pattern (the ratio of the etching rate of the silicon oxide film to the etching rate of the resist pattern) was as high as 4.0, and the dry etching resistance was excellent.

Comparative Example 1 A three-necked separable flask having an internal capacity of 500 ml was charged with 158 g of m-cresol, 18 g of p-cresol, 125 g of 37% by weight aqueous formaldehyde solution (hereinafter, simply referred to as “formalin”) and 0.06 g of an acid, with stirring. The internal temperature was kept at 100 ° C. for polycondensation for 3 hours. After completion of the reaction, the reaction product was immersed in a large amount of water to precipitate the novolac resin. The precipitate is then collected and 4
It was vacuum dried at 0 ° C. for 24 hours to remove water and unreacted materials to obtain an alkali-soluble novolak resin.

A solution of the resin composition was prepared by using this alkali-soluble novolac resin and treating it otherwise in the same manner as in Example 1.
Using this solution, a resist pattern was formed in the same manner as in Example 1 except that development was performed with a 2 wt% tetramethylammonium hydroxide aqueous solution. As a result, the minimum line width that faithfully reproduces the pattern mask is 1.2 μm.
The resist pattern had a resolution of 0.3 μm as compared with the resolution of Example 1. Further, the heat resistance temperature of the obtained resist pattern was as low as 110 ° C., and the selection ratio in dry etching resistance of this resist pattern was as bad as 2.1.

Examples 2 to 11 Phenols (A) and (B) shown in Table 1 were used in place of resorcinol, the carbonyl compound shown in Table 1 was used in place of acetaldehyde, and the others were the same as in Example 1. The same treatment was performed to prepare a solution of the resin composition of the present invention. After using this solution to form a resist pattern by treating in the same manner as in Example 1, the heat resistance temperature, dry etching resistance and resolution of the resist pattern were examined. As a result, as shown in Table 1, the heat resistance temperature was high. Moreover, it was excellent in dry etching resistance and resolution.

Examples 12 to 14 The resin of the present invention was prepared by using the alkali-soluble novolac resin obtained in Example 1, using the compounds shown in Table 2 as the 1,2-quinonediazide compound, and otherwise treating in the same manner as in Example 1. A solution of the composition was prepared. After treating with this solution in the same manner as in Example 1 to form a resist pattern,
As a result of examining the heat resistance temperature, the dry etching resistance and the resolution of the resist pattern, as shown in Table 2, the heat resistance temperature was high, and the dry etching resistance and the resolution were excellent.

(Effect of the Invention) The positive-type radiation-sensitive resin composition of the present invention is excellent in dry etching resistance, resolution and heat resistance, and is visible light, ultraviolet light, far ultraviolet light, X-ray, molecular beam, ion beam, electron. It is particularly useful as a positive resist for producing an integrated circuit for forming a resist pattern by irradiating radiation such as gamma rays and γ rays, and also as a positive resist for producing a mask.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Harada 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (56) References JP-A-59-84238 (JP, A) JP-A-59-84239 (JP, A) JP-A-59-86046 (JP, A) JP-A-59-88735 (JP, A) JP-A-57-101833 (JP, A) JP-A-56-1044 ( JP, A)

Claims (1)

[Claims] 1. At least one phenol (A) selected from resorcinol, pyrogallol and phlorogricinol and the following general formula (I): (Wherein R ₁ , R ₂ and R ₃ represent the same or different hydrogen atom or methyl group), and the phenols (B) are represented by a molar ratio of (A) / (B) = 1/99. -10
A positive radiation-sensitive resin composition comprising an alkali-soluble novolak resin obtained by polycondensation with a carbonyl compound and a 1,2-quinonediazide compound, which is used at a ratio of 0/0.