JP2800186B2 - Method for producing positive resist composition for producing integrated circuits - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing a resist composition having a high γ value.

<Conventional technology> A composition containing a compound having a quinonediazide group and a novolak resin utilizes the fact that the quinonediazide group is decomposed by irradiation with light of 300 to 500 nm to generate a carboxyl group, and becomes alkali-soluble from an alkali-insoluble state. And used as a positive resist. This positive type resist has a feature that the resolution is remarkably superior to that of the negative type resist, and is used for manufacturing integrated circuits such as ICs and LSIs.

In recent years, integrated circuits have been miniaturized due to higher integration, and submicron pattern formation is now required. As a result, a higher resolution (higher γ value) has been required for a positive resist.

However, in a resist composition containing a quinonediazide compound and a novolak resin, there has been a limit to the improvement of the γ value in a conventional combination of materials. For example, to improve the γ value, it is conceivable to increase the amount of the quinonediazide compound. However, increasing the amount of the quinonediazide compound leads to serious disadvantages such as a decrease in sensitivity and an increase in development residue. Therefore, there is a limit to the improvement of the γ value by the conventional technique.

<Problems to be Solved by the Invention> An object of the present invention is to produce a positive resist composition having a high γ value as an integrated circuit production operation.

The present inventors have found that, when a radiation-sensitive component containing a large amount of a quinonediazidesulfonic acid diester of a polyhydric phenol compound having a valency of 3 or more is used, the γ value is remarkably improved, and the present invention has been completed.

<Means for Solving the Problems> That is, the present invention relates to a quinonediazide sulfonic acid ester of a phenol compound, wherein at least a phenol nucleus is present in a high-performance liquid chromatography pattern measured using a detector using ultraviolet light of 254 nm. 2
A quinonediazidosulfonic acid diester of a phenol compound having three or more valences having a pattern area of 50% or more of the entire pattern area is selected as a radiation-sensitive component, and this radiation-sensitive component is mixed and dissolved in a solvent together with a novolak resin. Accordingly, the present invention provides a method for producing a positive resist composition for producing an integrated circuit.

The trivalent or higher phenol compound having at least two phenol nuclei as defined herein refers to a compound having at least two benzene rings each having at least one phenolic hydroxyl group in the molecule and having a total of 3 phenolic hydroxyl groups. Or more, and includes various polyhydroxy compounds having a plurality of benzene rings. However, even a phenol compound having a valence of 3 or more has only one benzene ring and has 3 A compound to which two or more phenolic hydroxyl groups are bonded, or a compound having a plurality of benzene rings,
Compounds in which three or more phenolic hydroxyl groups are bonded to only one benzene ring and no phenolic hydroxyl group is bonded to other benzene rings are excluded. Among such quinonediazide sulfonic acid esters of polyhydric phenol compounds, the ratio of the area of the diester in the high performance liquid chromatography pattern is 60% or more of the entire pattern area,
Further, those having 80% or more are more preferable.

As the quinonediazide sulfonic acid ester of a trivalent or higher phenol compound, there may be various methods for producing a radiation-sensitive component containing a large amount of the diester compound of the present invention. For example, the following method may be used. Can be adopted.

First, if a polyhydric phenol compound having the following specific structure is used, a diester is preferentially synthesized.

The quinonediazidesulfonic acid esterification of the phenol compound can be carried out according to a known method.
For example, by condensing naphthoquinonediazidesulfonic acid halide or benzoquinonediazidesulfonic acid halide with the above phenol compound in the presence of a weak alkali such as sodium carbonate or triethylamine,
A quinonediazidesulfonic acid ester is obtained.

Another method for obtaining a radiation-sensitive component containing a large amount of a diester is to use chloroform as a solvent during the reaction of obtaining a quinonediazidesulfonic acid ester by condensing a quinonediazidesulfonic acid halide with a polyhydric phenol compound. No. The polyhydric phenol compound in this case is not limited to a specific structure, and various compounds used for producing a radiation-sensitive component of a positive resist can be used. Other solvents exhibiting the same effect as chloroform include trichloroethane, trichloroethylene, dichloroethane and the like.

In the present invention, one kind of the above-mentioned quinonediazide sulfonic acid ester may be used, or two or more kinds thereof may be used. In the present invention, a quinonediazidesulfonic acid ester of another polyhydric phenol compound may be added as long as the effect is not inhibited. Other polyhydric phenol compounds include hydroquinone, resorcin, phloroglucin, alkyl gallate, 2,4-dihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, and 2,3,3 ', 4-tetrahydroxybenzophenone , 2,3,4,4'-tetrahydroxybenzophenone,
Tetrahydroxybenzophenones such as 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,3,3', 4,4'-
Examples thereof include pentahydroxybenzophenones such as pentahydroxybenzophenone and 2,3,3 ', 4,5'-pentahydroxybenzophenone. However, even when using the quinonediazidesulfonic acid ester of these polyhydric phenol compounds, in the present invention, the entire quinonediazidesulfonic acid ester of the polyhydric phenol compound is subjected to high-performance liquid chromatography using a detector using ultraviolet light of 254 nm. It is important that the pattern area of a quinonediazidesulfonic acid diester of a trivalent or higher phenol compound having at least two phenol nuclei has a pattern area of 50% or more of the total pattern area as measured by the above.

The present invention is a quinonediazide sulfonic acid ester of a phenol compound as a radiation-sensitive component of a positive resist composition, wherein a phenol nucleus is present in a high-performance liquid chromatography pattern measured using a detector using ultraviolet light of 254 nm. It is essential that the pattern area of the quinonediazidesulfonic acid diester of a phenol compound having at least two trivalent or higher valences be 50% or more of the entire pattern area. A mixture containing other ester forms, such as monoesters and / or higher esters, together with the form. As is clear from the above description, this selection includes a tri- or higher-valent phenol having at least two phenol nuclei from a quinonediazidesulfonic acid ester obtained by esterification of any phenol compound including a tri- or higher phenol compound. The quinonediazidesulfonic acid diester of the compound may have a pattern area of 50% or more of the entire pattern area. Select the esterification, the area of the diester in the high performance liquid chromatography pattern is 50% of the total pattern area
% Or a condition in which a diester is preferentially generated during esterification, and the area of the diester in the high performance liquid chromatography pattern is 50% or more of the entire pattern area. The aspect which performs it is also included.

The novolak resin used in the present invention is obtained by an addition condensation reaction between phenols and formaldehyde. Specific examples of the phenols used for producing the novolak resin include phenol, cresol, xylenol, ethylphenol, trimethylphenol, propylphenol, butylphenol, dihydroxybenzene, naphthols and the like. These phenols can be used alone or in combination of two or more. As formaldehyde to be subjected to an addition condensation reaction with phenols, an aqueous formaldehyde solution (formalin), paraformaldehyde and the like are used. In particular, formalin having a concentration of about 37% by weight is industrially mass-produced and is convenient.

The addition condensation reaction between phenols and formaldehyde is carried out according to a conventional method. The reaction is usually performed at 60-120 ° C for 2-3
Performed for 0 hours. In this reaction, an organic acid, an inorganic acid, a divalent metal salt or the like is usually used as a catalyst. Specific examples of the catalyst include oxalic acid, hydrochloric acid, sulfuric acid, perchloric acid,
Examples thereof include p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, formic acid, zinc acetate, and magnesium acetate. This addition condensation reaction may be performed in a bulk or using an appropriate solvent.

In the present invention, the addition amount of the quinonediazidesulfonic acid ester component (radiation-sensitive component) is preferably in the range of 15 to 50% by weight of the total solid components of the resist composition.

The preparation of the resist solution is performed by mixing and dissolving the quinonediazidesulfonic acid ester and the novolak resin in a solvent. The solvent used here preferably has an appropriate drying rate and gives a uniform and smooth coating film by evaporation of the solvent. Such solvents include ethyl cellosolve acetate,
Methyl cellosolve acetate, ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether acetate, butyl acetate, methyl isobutyl ketone,
Xylene and the like can be mentioned.

The resist composition obtained by the above method may further contain a small amount of a resin or a dye as an additive, if necessary.

The positive resist composition thus obtained is applied on a substrate such as a silicon wafer and dried to form a resist film. The resist film is irradiated with radiation (patterning exposure) through a mask, and then developed with an alkaline developer, whereby a resist pattern is formed with high resolution.

<Effects of the Invention> According to the present invention, a positive resist composition having a high γ value can be obtained as an integrated circuit manufacturing operation. Further, this positive resist composition has no problems such as an increase in development residue.

<Examples> Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The percentages and parts in the examples are by weight unless otherwise indicated.

Production Example 1 (Production of Radiation-Sensitive Component Having Many Diester Compounds) In a 300-ml three-necked flask having an inner volume of 300 ml, 6.00 g of a compound represented by the following formula (I) obtained by condensation of resorcinol and acetone, naphthoquinone- (1,2) -diazide- (2)-
10.75 g of 5-sulfonic acid chloride (reaction molar ratio 1: 2),
And 168 g of dioxane were charged, followed by stirring to complete dissolution. After that, immerse the flask in a water bath with stirring,
The reaction temperature was controlled at 20 to 25 ° C., and 4.45 g of triethylamine was added dropwise over 30 minutes using a dropping funnel.
Next, stirring was continued for 4 hours while maintaining the reaction temperature at 20 to 25 ° C. After the reaction, the reaction mass is charged into deionized water,
Next, the mixture was dried and dried to obtain a radiation-sensitive component B.

Production Example 2 (same as above) A radiation-sensitive component was prepared in the same manner as in Production Example 1 except that the compound represented by the following formula (II) was used in an equimolar amount instead of the compound represented by the formula (I). Obtained. This is designated as radiation-sensitive component C.

Production Example 3 (Production of a radiation-sensitive component having a small amount of diester compound: for comparison) Production was carried out except that an equimolar amount of 2,3,4-trihydroxybenzophenone was used instead of the compound represented by the formula (I). A radiation-sensitive component was obtained in the same manner as in Example 1. This is designated as radiation-sensitive component D.

Production Example 4 (Production of Radiation-Sensitive Component Having Many Diester Compounds) In a three-necked flask having an inner volume of 300 ml, 4.60 g of 2,3,4-trihydroxybenzophenone and naphthoquinone- (1,2)-
10.75 g of diazide- (2) -5-sulfonic acid chloride
(Reaction molar ratio 1: 2), and after charging 155 g of chloroform, the flask was immersed in a water bath with stirring, the reaction temperature was controlled at 20 to 25 ° C., and 4.45 g of triethylamine was added for 30 minutes using a dropping funnel. Was dropped. Thereafter, stirring was continued for 4 hours while maintaining the reaction temperature at 20 to 25 ° C. After the reaction, chloroform was evaporated using a rotary evaporator, and then 200 g of dioxane was added to completely dissolve the chloroform. It was charged into ion-exchanged water, then filtered and dried to obtain a radiation-sensitive component E.

Production Example 5 (same as above) Instead of 2,3,4-trihydroxybenzophenone,
A radiation-sensitive component was obtained in the same manner as in Production Example 4, except that the compound represented by the formula (II) used in Production Example 2 was used in an equimolar amount. This is designated as radiation-sensitive component F.

Production Example 6 (Production of a radiation-sensitive component having a small amount of diester: for comparison) Instead of the compound represented by the formula (I), 2,3,4,4'-tetrahydroxybenzophenone was used to prepare naphthoquinone-
A radiation-sensitive component G was obtained in the same manner as in Production Example 1, except that the reaction molar ratio with (1,2) -diazide- (2) -5-sulfonic acid chloride was 1: 3.

Liquid chromatographic analysis was performed on the radiation-sensitive components B to G obtained in the above Production Examples 1 to 6. The liquid chromatogram was obtained by using a column of Lichrosolve RP-10 (10 μm) 4 mmφ × 250 mm on an LC-4A chromatograph manufactured by Shimadzu Corporation and using water as a carrier solvent, 57.5% of water, 36.1% of tetrahydrofuran, 6.4% of methanol. % And formic acid 1% at a rate of 1.0 ml / min. A 254 nm UV detector was used for the chromatography. The peak of the diester compound was analyzed by high performance liquid chromatography (HPL
After fractionation in C), identification was performed by mass spectrometry using secondary ion mass spectrometry (SIMS).

Examples, Reference Examples and Comparative Examples Each of the radiation-sensitive components obtained in Production Examples 1 to 6 was dissolved together with a novolak resin in 48 parts of ethyl cellosolve acetate with the composition shown in Table 1 to prepare a resist solution.
The prepared resist solution was passed through a 0.2 μm Teflon filter. This resist solution was applied to a 1.3 μm thick silicon wafer that had been cleaned by a conventional method using a spin coater. The coated silicon wafer was baked on a hot plate at 100 ° C. for 60 seconds. Next, the wafer was exposed to light using a reduced projection exposure machine (DSW4800 manufactured by GCA, NA = 0.28) having an exposure wavelength of 436 nm (g line) while changing the exposure amount stepwise. This was developed with a developing solution SOPD manufactured by Sumitomo Chemical Co., Ltd. for 1 minute to obtain a positive pattern.

For the obtained pattern, the normalized film thickness (= remaining film thickness / initial film thickness) was plotted with respect to the logarithm of the exposure amount, the slope θ was obtained, and tan θ was defined as the γ value. HPLC of radiation-sensitive components
The results are shown in Table 1 together with the diester content in area ratio.
Shown in

──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Kuwana 3-1-198, Kasuganaka, Konohana-ku, Osaka-shi, Osaka Sumitomo Chemical Industries Co., Ltd. (72) Inventor Booko Ooi Kasuga, Konohana-ku, Osaka-shi, Osaka No. 3-98, No. 98, Sumitomo Chemical Co., Ltd. (56) References JP-A-2-10348 (JP, A) JP-A-62-153950 (JP, A) JP-A-62-150245 (JP, A A) JP-A-57-135947 (JP, A) JP-A-54-63818 (JP, A) JP-A-58-150948 (JP, A) JP-A-58-17112 (JP, A) −18015 (JP, B1) (58) Field surveyed (Int. Cl. ⁶ , DB name) G03F ^7/ 00-7/18

Claims (2)

(57) [Claims] 1. A quinonediazide sulfonic acid ester of a phenol compound, which is a trivalent or higher phenol compound having at least two phenol nuclei in a high-performance liquid chromatography pattern measured with a detector using ultraviolet light of 254 nm. Quinonediazidesulfonic acid diester pattern area is 50% of total pattern area
The method for producing an integrated circuit, wherein a mixture of the diester and another ester is selected as a radiation-sensitive component, and the radiation-sensitive component is mixed and dissolved in a solvent together with a novolak resin. A method for producing a positive resist composition. 2. The radiation-sensitive component according to claim 1, wherein the quinonediazide sulfonic acid diester of a phenol compound having at least two phenol nuclei and having a valence of 3 or more has a pattern area of 60% or more of the entire pattern area. the method of.