JPH05173327A - Positive type photoresist composition and method for forming resist pattern - Google Patents

Abstract

PURPOSE:To improve balance of sensitivity, resolution, and heat resistance and to enhance aptitude to microfabrication by incorporating a specified compound, an alkali-soluble resin, and naphthoquinone-1,2-diazido photosensitive agent. CONSTITUTION:The resist pattern is obtained by applying this photoresist composition on a substrate and exposing and developing it, and this composition comprises the alkali-soluble resin and the naphthoquinone-1,2-diazido photosensitive agent and the compound represented by formula in which each of m and n is 0, 1, or 2; and each of R1 and R2 is, independently, II, methyl, or ethyl. It is preferred to use the compound of formula I in an amount of 5-25% of the total amount of the alkali-soluble resin and as the alkali-soluble resin an alkali-soluble novolak resin obtained removing 40-90% of the, low molecular weight fraction of <=3000 average molecular weight in terns of polystyrene. The novolak resin is obtained by additionally condensing phenols with aldehydes in the presence of acid catalysts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive photoresist composition and a method for producing a resist pattern using the same, which is used in a semiconductor device manufacturing process such as IC and LSI and has a balance of sensitivity, resolution and heat resistance. The present invention relates to a positive photoresist composition for fine processing and a method for producing a resist pattern using the same.

[0002]

2. Description of the Related Art Currently used positive photoresist compositions comprise an alkali-soluble resin and a naphthoquinonediazide compound as a photosensitizer. For example, an example containing a novolak resin composed of cresol-formaldehyde and trihydroxybenzophenone-naphthoquinone-1,2-diazide-5-sulfonate is disclosed in Japanese Examined Patent Publication No.
No. 7-18015.

[0003]

The degree of integration of semiconductor devices is increasing year by year, and in the manufacture of VLSI,
Designs have come to be designed with a line width of 1 μm or less. A photoresist suitable for such fine processing has been desired, but the conventional positive photoresist composition tends to have lower sensitivity and heat resistance when the resolution is improved. The present invention relates to a positive photoresist composition for microfabrication having a good balance of sensitivity, resolution and heat resistance, and a method for producing a resist pattern using the same.

[0004]

The present invention has the general formula (I)

[Chemical 5] (Wherein, m and n represent an integer of 0 to 2, R ₁ and R ₂ may be the same or different and represent a hydrogen atom, a methyl group or an ethyl group), an alkali The present invention relates to a positive photoresist composition containing a soluble resin and a naphthoquinone-1,2-diazide photosensitizer, and a method for producing a resist pattern by coating, exposing and developing the positive photoresist composition on a substrate.

The compound represented by the general formula (I) used in the positive photoresist composition of the present invention is a known compound. Among the compounds represented by the general formula (I),

[Chemical 6] Is preferred. The content of the compound represented by the general formula (I) is 5 to 25 relative to 100 parts by weight of the total amount of the alkali-soluble resin.
It is preferably part by weight.

Examples of the alkali-soluble resin used together with the compound represented by the general formula (I) include alkali-soluble novolac resin, polyhydroxystyrene and alkali-soluble silicone resin. The alkali-soluble novolac resin is a known compound and is synthesized by addition-condensing phenols and aldehydes with an acid catalyst. Examples of phenols include phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, 2,5-xylenol, 2,6-xylenol, 3,5-. Xylenol, 3,4-xylenol, α-naphthol, β-naphthol and the like can be used. Formaldehyde, paraformaldehyde, acetaldehyde and the like can be used as the aldehydes. Examples of the acid catalyst include oxalic acid, hydrochloric acid, sulfuric acid, acetic acid, formic acid and the like. This synthesis is, for example, 5
After the addition condensation reaction at 0 to 130 ° C. for 1 to 15 hours, 1
Water and unreacted monomers are removed at 00 to 250 ° C. Among the alkali-soluble novolac resins, a resin obtained by removing 40 to 90% of a low molecular weight portion having a polystyrene reduced weight average molecular weight of 3000 or less by fractionation or the like is preferable.

The naphthoquinone used in the present invention is also
The 1,2-diazide sensitizer can be obtained by subjecting a naphthoquinonediazide sulfonyl halide and a polyhydroxy compound to a condensation reaction in the presence of a reaction solvent and a basic catalyst. As the naphthoquinone diazide sulfonyl halides, naphthoquinone-1,2-diazide-5-sulfonyl halide, naphthoquinone-1,2-diazide-4-sulfonyl halide and the like can be used. Here, examples of the halogen atom of the halide include a chlorine atom, a bromine atom, an iodine atom and a fluorine atom. As the polyhydroxy compound, 2,3,4-trihydroxybenzophenone, 2,
3,4,4'-tetrahydroxybenzophenone, 2,
2 ', 4,4'-tetrahydroxybenzophenone,
2,3,4,2 ', 3'-pentahydroxybenzophenone, 2,3,4,3', 4 ', 5'-hexahydroxybenzophenone, bis (2,3,4-trihydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) propane, 4b, 5,9b, 10-tetrahydro-1,3,6,8-tetrahydroxy-5,10-
Dimethylindeno [2,1-a] indene, Tris (4
-Hydroxyphenyl) ethane and the like. In the condensation reaction, the reaction temperature is preferably 0 to 40 ° C., and the reaction time is preferably 1 to 10 hours. As the reaction solvent, a solvent such as dioxane, acetone, methyl ethyl ketone, tetrahydrofuran, diethyl ether, N-methylpyrrolidone or the like is used. Examples of the basic catalyst include sodium carbonate, sodium hydroxide, sodium hydrogen carbonate, potassium carbonate, potassium hydroxide, trimethylamine, triethylamine, pyridine, dimethylaminopyridine and the like.

Alkali-soluble resin and naphthoquinone-1,
The compounding ratio of the 2-diazide photosensitizer is preferably naphthoquinone-1,2 with respect to 100 parts by weight of the alkali-soluble resin.
-Diazide photosensitizer 10 to 100 parts by weight, more preferably 15 to 40 parts by weight.

The positive photoresist composition according to the present invention is generally used by dissolving it in a solvent. As the solvent for dissolving the alkali-soluble resin and the naphthoquinone-1,2-diazide photosensitizer, ethyl cellosolve acetate and methyl are used. Cellosolve acetate, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate and the like can be used. Usually, 200 to 650 parts by weight of the solvent is used for 100 parts by weight of the total of the alkali-soluble novolak resin and the compound represented by the general formula (I). Dyes, surfactants and the like can be added to the positive photoresist composition of the present invention as necessary.

A good resist pattern is obtained by coating and drying the above positive photoresist composition on a silicon substrate or the like by a known method using a coater or the like, and then exposing and developing it using a reduction projection exposure apparatus or the like. You can As the developing solution used in the present invention, sodium hydroxide,
Examples thereof include potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine and tetramethylammonium hydroxide. Further, an alcohol or a surfactant may be added to the above developer for use.

[0011]

EXAMPLES Examples of the present invention will be described. (A) Synthesis of alkali-soluble novolak resin (1) Synthesis of alkali-soluble novolak resin (1) m-cresol 162.2 g, p-cresol 108.
1 g, 121.7 g of a 37% by weight aqueous formalin solution and 1.125 g of oxalic acid were charged into a reaction vessel, and then the reaction temperature was raised to 100 ° C. with stirring and the reaction was carried out for 3 hours. After the reaction, the temperature was raised to 180 ° C., and water and unreacted monomers were removed by reducing the pressure. After cooling to room temperature, an alkali-soluble novolak resin (1) was obtained. The polystyrene reduced weight average molecular weight was 4,319. (2) Synthesis of alkali-soluble novolak resin (2) Alkali-soluble novolak resin is obtained by dissolving 100 g of alkali-soluble novolak resin in 200 g of ethyl cellosolve acetate, charging the mixture with 850 g of toluene, collecting the precipitated portion, and drying. (2) was obtained. The polystyrene reduced weight average molecular weight was 10994 (86.7% of the low molecular weight portion having a polystyrene reduced weight average molecular weight of 3000 or less was removed). (3) Synthesis of alkali-soluble novolak resin (3) m-cresol 148.7 g, p-cresol 81.1
After charging g, 3,5-xylenol 45.8 g, 37 wt% formalin aqueous solution 146.1 g and oxalic acid 2.926 g into the reaction vessel, the reaction temperature was raised to 100 ° C. with stirring and the reaction was carried out for 3 hours. It was After the reaction, the temperature was raised to 180 ° C., and water and unreacted monomers were removed by reducing the pressure. After cooling to room temperature, an alkali-soluble novolak resin was obtained. The polystyrene reduced weight average molecular weight was 6,500. Alkali-soluble novolak resin (3) was obtained by dissolving 100 g of this alkali-soluble novolak resin in 200 g of ethyl cellosolve acetate, charging it in 1250 g, collecting the precipitated portion, and drying. The polystyrene reduced weight average molecular weight was 9080 (the low molecular weight portion having a polystyrene reduced weight average molecular weight of 3000 or less was 7
1.6% removal).

(B) Synthesis of Photosensitizers (1) to (2) (1) Synthesis of Photosensitizer (1) 4b, 5,9b, 10-tetrahydro-1,3,6,8
11.42 parts by weight of tetrahydroxy-5,10-dimethylindeno [2,1-a] indene and naphthoquinone-1,2-diazide-5-sulfonyl chloride 36.
00 parts by weight (3.5 mol ratio) was charged into a mixed solvent of dioxane 150 parts by weight and acetone 50 parts by weight together with 0.6548 parts by weight of dimethylaminopyridine, and 13.6 parts by weight of triethylamine and 50.0 parts of dioxane with stirring.
A mixed liquid with parts by weight was gradually added dropwise and the reaction was carried out for 4 hours.
After the reaction was completed, the contents were dropped into a 1% by weight hydrochloric acid aqueous solution,
The resulting precipitate was filtered, washed with water, washed with methanol and dried to obtain a photosensitizer (1). (2) Synthesis of Photosensitivity (2) Tris (4-hydroxyphenyl) methane 13.06 parts by weight and naphthoquinone-1,2-diazide-5-sulfonyl chloride 36.00 parts by weight (3.5 mol ratio) are added. A mixed solution of 13.6 parts by weight of triethylamine and 50.0 parts by weight of dioxane was gradually added dropwise with stirring in a mixed solvent of 150 parts by weight of dioxane and 50 parts by weight of acetone together with 0.6548 parts by weight of dimethylaminopyridine, The reaction was carried out for 4 hours. After completion of the reaction, the content was dropped into a 1% by weight hydrochloric acid aqueous solution, and the resulting precipitate was filtered, washed with water, washed with methanol and dried to obtain a photosensitizer (2).

Examples 1 to 6, Comparative Example 1 Alkali-soluble novolak resin (1) obtained above,
A total of 25 parts by weight of (2) or (3) and the compound represented by the general formula (I) and 6 parts by weight of each of the photosensitizers (1) and (2) are combined as shown in Table 1 to obtain ethyl cellosolve. It was dissolved in 78 parts by weight of acetate to prepare a resist solution. These resist solutions were filtered using a 0.2 μm Teflon filter to prepare a resist composition. Each of these was spin-coated on a silicon wafer and baked on a hot plate at 90 ° C. for 90 seconds to obtain a 1.22 μm resist film. Then, exposure was performed using an i-line reduction projection exposure apparatus (i-line stepper LD-5010i manufactured by Hitachi Ltd.) while changing the exposure amount stepwise between 50 and 300 mJ / cm ² . Then, post exposure bake was performed on a hot plate at 110 ° C. for 90 seconds. The development was carried out for 1 minute using a 2.38 wt% tetramethylammonium hydroxide aqueous solution, followed by washing with water and drying on a hot plate at 110 ° C. for 50 seconds. The resist pattern on the silicon wafer thus obtained was observed and evaluated by a scanning electron microscope.
The raw results are shown in Table 1. The sensitivity indicates the exposure amount for reproducing a mask pattern having a resolution of 1 μm. In addition, the minimum pattern size that can be resolved as a line-and-space is shown according to the dimension of the pattern in the exposure amount for reproducing a mask pattern with a resolution of 1 μm. Heat resistance is 50 μm
The silicon wafer on which the resist pattern was formed was baked in a convection oven for 20 minutes, and the upper limit temperature at which the resist pattern was not deformed was observed and examined by a scanning electron microscope. Table 1 shows that the positive photoresist composition of the present invention has a good balance of sensitivity, resolution and heat resistance.

[0014]

[Table 1] 1) The following compounds were used as the compound represented by the general formula (I).

[Chemical 7]

[0015]

The positive photoresist composition according to the present invention has a good balance of sensitivity, resolution and heat resistance, whereby a resist pattern suitable for microfabrication can be obtained, and it is particularly useful for semiconductor device production. ..

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mamoru Sasaki 4-13-1, Higashimachi, Hitachi-shi, Ibaraki Hitachi Chemical Co., Ltd. Yamazaki factory

Claims (6)

[Claims] 1. A compound represented by the general formula (I): (Wherein, m and n represent an integer of 0 to 2, R ₁ and R ₂ may be the same or different and represent a hydrogen atom, a methyl group or an ethyl group), an alkali A positive photoresist composition comprising a soluble resin and a naphthoquinone-1,2-diazide photosensitizer. 2. A compound represented by the general formula (I) is: The positive photoresist composition according to claim 1, which is 3. A compound represented by the general formula (I) is: The positive photoresist composition according to claim 1, which is 4. A compound represented by the general formula (I) is: The positive photoresist composition according to claim 1, which is 5. The alkali-soluble resin contains 40 to 9 low molecular weight parts having a polystyrene reduced weight average molecular weight of 3000 or less.
The positive photoresist according to claim 1, which is an alkali-soluble novolak resin obtained by removing 0%, and the compound represented by the general formula (I) is 5 to 25 parts by weight with respect to 100 parts by weight of the total amount of the alkali-soluble resin. Composition. 6. A method for producing a resist pattern, which comprises coating, exposing and developing a positive photoresist composition according to claim 1 on a substrate.