KR920005774B1 - Positive photoresist composition - Google Patents

Abstract

A positive photoresist composition comprises 10-50 wt. pts. (pref. 20-30 wt. pts.) quinone diazide compound of formular (I) [where D1-3 is hydrogen, benzoquinone-1,2-diazide-4-sulfonyl, naphtoquinone-1,2-diazide-4-sulfonyl or naphtoquinone-2,1-diazide-4-sulfonyl radical, and R is C1-5 alkyl, alkoxy or phenyl group , 20-90 wt. pts. (pref. 65085 wt. pts.) novolak resin of formular (II) [where R is hydrogen or methyl ,0-10 wt. pts. additive of formular (III) [where R1 is hydrogen or methyl and R2 is hydrogen, methyl and alkoxy group and 50-90 wt. pts. solvent. The composition has a good resolving power and contrast property, and is useful for producing a semiconductor device.

Description

Positive Photoresist Composition for Semiconductor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition which is used in a photolithography process to form a positive image when manufacturing a microcircuit of a highly integrated semiconductor device such as LSI and VLSI, and relates to a method of manufacturing a photosensitive resin composition having excellent resolution and contrast.

In general, the photosensitive resin is composed of a composition of a photoactive material, a binder resin, a participant, and a solvent whose chemical and physical properties are changed by light such as ultraviolet rays, electron beams, and x-rays.

Among photosensitive resins currently commercialized, ultraviolet photoresists include positive photoresists composed of novolak resins and diazo compounds, and negative photoresists composed of cyclized rubbers and diazide compounds. In addition, the ultraviolet rays, electron beams, and X-ray resists include positive resists such as polymethyl methacrylate, polymethylisopropenyl ketone, polyglycidyl metaglutami, and polyglycidyl methacrylate, halogenated polystyrene, and the like. There is a negative resist. The positive photoresist for ultraviolet rays has been reported in patents such as USP 3,201,239, USP 3,402,044, USP 3,184,310, USP 3,759,711, USP 3,900,325, USP 4,104,070, USP 4,115,128, USP 4,196,003, USP 4,555,469, USP 4,622,283.

The quinone diazide compound used as a photoactive material in the positive photoresist composition, when mixed with novolak resin, reduces the solubility of the novolak resin in an alkali aqueous solution to 1/100 or less, but when UV is irradiated, It is converted to carboxylic acid, solubilized in alkaline aqueous solution, and its solubility is increased by 2,000-3,000 times compared to the mixture without UV irradiation. Therefore, photoresists containing quinone azide compounds using these properties have been used in fields requiring microcircuit processing and positive image of semiconductor devices.

The present invention relates to a positive photoresist composition for semiconductors, wherein the composition according to the present invention consists of a photoactive material, a binder resin, an additive, and a solvent. Quinone diazide compounds which are photoactive substances include benzoquinone-1, 2-diazide-4-sulfohalide, naphthoquinone-1, 2-diazide-5-sulfohalide, naphthoquinone-1 and 2-diazide. 4-sulfohalide, naphthoquinone-2, 1-diazide-5-sulfohalide, naphthoquinone-2, 1-diazide-4-sulfohalide and the like 2, 3, 4-trihydroxy benzophenone, 3, 4, 5-trihydroxy benzophenone, 2, 4, 4'-trihydroxy benzophenone, 2, 3, 4, 4'-tetrahydroxy benzophenone, 2, 3, 3 ', 4, 4 There are compounds that esterify '-pentahydroxy benzophenone, pyrogarol, resorcinol and the like and are used as photoactive materials.

Binder resin is an important component for the preparation of the photoresist composition and is an important component to be designed in consideration of solubility, heat resistance, and etching resistance in an aqueous alkali solution. As a binder resin suitable for positive photoresist, novolak resin by condensation of phenol and formaldehyde, novolak resin by condensation of cresol and formaldehyde, polyhydroxy styrene, polyvinyl alcohol and the like are used. These binder resins are materials that affect developability, resolution, pattern cross-sectional shape, and etch resistance, and should have good mechanical strength and compatibility with photoactive materials. It should not be affected.

As a solvent used in the preparation of the photoresist using the photoactive component and the binder resin, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, butyl cellosolve Solvents, such as acetate, acetone, methyl ethyl ketone, cyclohexane, dioxane, xylene normal butyl acetate, and dichloroethylene, are used individually or in mixture of 2 or more types.

In addition, a plasticizer, a stabilizer, a surfactant, and a contrast enhancer are used in the present invention as a photoactive material in order to enhance the applicability of the semiconductor device manufacturing process and the storage property of the photoresist.

Wherein D is H or benzoquinone-1, 2-diazide-4-sulfonyl radical naphthoquinone-1, 2-diazide-4-sulfonyl radical, naphthoquinone-1, 2-diazide-5- Represents one radical among sulfonyl radicals, naphthoquinone-2, 1-diazide-4-sulfonyl radicals, naphthoquinone-2, 1-diazide-5-sulfonyl radicals, and _{1 of} D ₁ -D ₃ More than one H is substituted with quinonediazide sulfonyl radicals. R may have H, or C ₁ -C ₅ alkyl, alkoxy or phenyl groups.

The compound of formula (I) exhibits excellent structural change upon irradiation with ultraviolet rays and thus shows a difference in solubility in an alkali solution of exposed and non-exposed portions, thereby making it possible to prepare a positive photoresist. The content of the compound of formula (I) in the photoresist is preferably 10-50% and more preferably 20-30% of the total solids.

In addition, as a binder resin, three types of novolak resins having the following structural formula (II) were synthesized by condensation reaction between cresol and formaldehyde:

R is a hydrogen atom or a methyl group in one of the ortho, meta or para positions. Novolak Resin is characterized by:

(A) The first novolak resin is phenol novolak resin and its weight average molecular weight is 5,000-7,000

(B) The second novolak resin is metacresol novolak resin with a weight average molecular weight of 20,000-25,000

(3) The third novolak resin is cresol noborac copolymerized with 50-100% of methacresol and 50-0% of paracresol. The weight average molecular weight is 9,000-12,000 photoresists of novolak resin Is 20-90% good relative to the total solids, more preferably 65-85%. Particularly, the content of the first novolak resin in the novolak resin is 0-30%, and the content of the second novolak resin is 30-70%. In addition, the content of the third novolak resin is 0-70% is good.

As a solvent, a mixed solvent of 80-100% ethyl cellosolve acetate, 0-10% normal butyl acetate, and 0-10% zylene was used.

In order to improve the suitability of the photoresist in the semiconductor process, the additive of the following structural formula (III) was used.

R ₁ may be a hydrogen atom, a methyl group, R ₂ may be a hydrogen atom, an alkyl group or an alkoxy group.

The additive content of formula (III) in the photoresist is 0-10% based on the total amount.

Hereinafter, the present invention will be described in detail with reference to synthesis examples and examples.

Synthesis Example 1

Dissolve 32.4 g (0.1 mole) of para-naphthol benzein and 67.13 g (0.25 mole) of naphthoquinone-1, 2-diazide-5-sulfonylcloid in 300 ml of dioxane. Stir the solution well and add 10% sodium carbonate solution dropwise. After complete addition, the reaction mixture was stirred for 30 minutes, and the resulting precipitate was filtered and poured into a diluted aqueous sulfuric acid solution to precipitate the reaction. The precipitate was filtered off, washed with pure water and dried to obtain a photoactive material.

Synthesis Example 2-4

Phenol, metacresol, paragresol and formaldehyde were added to the reactor at 110 ° C. in each ratio and Zn (OAc) .2H ₂ O was added for reaction for about 30 minutes, followed by oxalic acid, ethyl cellosolve acetate, and water. Then, 10% sodium carbonate was added and neutralized to terminate the reaction, thereby adjusting the molecular weight. The reaction solution was precipitated in water, filtered and dried to synthesize novolak resin.

The average molecular weight and the mixing ratio of phenol, metacresol and paracresol of the novolak resin prepared in this manner are shown in Table 1.

TABLE 1

Example 1

25.0 g of novolak resin synthesized in 6.82 g (synthesis example 4) synthesized in [Synthesis Example 1] completely dissolved in 75 g of the mixed solvent mentioned for the additive 1 g of Figure (III), and then filtered through a 0.2 μm filter. do. The photoresist was spin-coated on a 6-inch silicon wafer, followed by soft baking at 110 ° C. for 90 seconds to obtain a photosensitive film having a thickness of 1.2 μm. Using this photosensitive film stepper (5: 1), 436 nm ultraviolet rays are exposed to 65 zones with increasing energy of 5 msec from 80 msec to 400 msec. The exposed wafer is developed in a puddle manner at 25 ° C. for 60 seconds using a tetramethylammonium hydroxy solution. After hard-baking the developed wafer, the residual film ratio of the photosensitive resin remaining in each portion is measured, and a gamma value is obtained from the tangent slope of the contrast curve from the fully developed energy (threshold energy: ET) and the residual film ratio. In addition, by observing the pattern of the zone (ZONE) that is twice the energy of the threshold energy, the cross-sectional angle of the pattern was obtained.

Comparative Example 1

It is the same as that of [Example 1] except having not added an additive compared with [Example 1].

Example 2

In comparison with Example 1, 6.25 g of novolak resin synthesized in Synthesis Example 2 and 6.25 g of noborac resin synthesized in Synthesis Example 3 were added. Except for the same as in Example 1.

Example 3

Compared with [Example 2], it is the same as [Example 2] except having added 12.5 g of novolak resin synthesize | combined in 6.25g [synthesis example 4] synthesize | combined in [Synthesis example 3].

Example 4

It is the same as that of [Example 3] except having added 0.5 g of additives compared with [Example 3].

Example 5

It is the same as that of [Example 4] except having added 0.25 g of additives compared with [Example 4].

Table 2 summarizes the above examples and comparative examples. As shown in Table 2, the gamma value increased as the cresol content, especially the paracresol content, of the binder resin increased, and the threshold energy increased when the additive was added.

TABLE 2

Claims (3)

The photoactive substance which occupies 10-50 weight part with respect to a total solid more preferably 20-30 weight part is the quinone diazide compound of following General formula (I); Novolak resin of the following general formula (II) as binder resin which occupies 20-90 weight part with respect to a total solid, more preferably 65-85 weight part; Additive of the following general formula (III), which accounts for 0-10 parts by weight based on the total composition; And a positive photoresist composition for a semiconductor, which comprises 50-90 parts by weight of the total composition and a solvent dissolving the three components.

Wherein D is H or benzoquinone-1, 2-diazide-4-sulfonyl radical naphthoquinone-1, 2-diazide-4-sulfonyl radical, naphthoquinone-1, 2-diazide-5- Represents one radical among sulfonyl radicals, naphthoquinone-2, 1-diazide-4-sulfonyl radicals, naphthoquinone-2, and 1-diazide-5-sufonyl radicals, and _{1 of} D ₁ -D ₃ More than one H is substituted with quinone diazide sulfonyl radicals. R may have H, or a C ₁ -C ₅ alkyl, alkoxy or phenyl group.

Where R is a hydrogen atom or a methyl group in one of the ortho, methane, or para positions.

R ₁ may be a hydrogen atom, a methyl group, R ₂ may be a hydrogen atom, an alkyl group or an alkoxy group. The phenol novolak resin according to claim 1, wherein the novolak resin, which is a binder resin, has a first weight average molecular weight of 5,000 to 7,000; Second, 30-70% by weight of metacresol novolak resin having a weight average molecular weight of 20,000-25,000; Third, the positive photoresist composition for semiconductors consisting of cresol novolak resin copolymerized with 50-100% metacresol and 0-50% paracresol having a weight average molecular weight of 9,000-12,000. The method of claim 1, wherein the solvent for dissolving the photoactive material, binder resin and additives is methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, butyl cellosolve acetate A positive photoresist composition for a semiconductor comprising xylene, normal butyl acetate, methyl ethyl ketone, cyclohexane, isoamyl ketone, acetone, dioxane, or a mixed solvent of two or more thereof.