JPH0413143A - Resist composition - Google Patents

Abstract

PURPOSE:To prevent halation and notching on a high-reflective substrate, to stabilize a pattern against prebaking, to enhance resolution, and to restrain deterioration in sensitivity due to addition of a light absorbing agent by incorpo rating a specified compound as the light absorbing agent. CONSTITUTION:The compound to be added as th light absorbing agent is represented by formula I in which each of R1 - R3 is independently H, optionally substituted alkyl, or halogen; each of X and Y is independently cyano, -COOR, or CONHR'; R is alkyl; and R' is H or aryl. It is preferred to use the resist composition containing this compound as the positive type resist composition and the composition comprising a novolak resin obtained by polycondensing some of phenols with formaldehyde, and 1,2-quinonediazido compound, thus permitting halation and notching on the high-reflective substrate to be prevented, a pattern to be stabilized against prebaking, resolution to be enhanced, and deterioration of sensitivity due to addition of the agent to be restrained.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a resist composition.

More specifically, the present invention relates to a resist composition particularly suitable for forming fine patterns on high reflectance substrates such as aluminum in the production of semiconductor devices such as ICs and LSIs.

(Prior art) Conventionally, in the manufacture of integrated circuits such as LSIs, resist compositions containing a quinone diazide photosensitizer and a novolak resin, resist compositions containing a bisazide photosensitizer and a degraded rubber resin, etc. have been used. ing.

When manufacturing integrated circuits, resist compositions are used to form fine patterns on various substrates, but on high reflectance substrates such as aluminum, aluminum-silicon, and polysilicon, conventional resist compositions cannot be used to form fine patterns on the substrate surface. Due to the reflection of light on the side surfaces of the step and the steps, a photosensitive phenomenon occurs in unnecessary areas, resulting in a problem called notching halation.

In order to improve the above problem and prevent a decrease in resolution, Japanese Patent Publication No. 1983-37562 published a dye (oil yellow (C, l-11020:
) has been proposed as a light absorbing agent. Thereby, it is possible to rapidly reduce the amount of light that passes through the resist layer, and to reduce the amount of light that goes around to the light-blocking area.

However, the addition of a light absorbing agent generally causes an undesirable problem in that the sensitivity of the resist composition is greatly reduced, resulting in a reduction in productivity during semiconductor manufacturing.

In addition, a resist film is usually created by applying a resist composition containing a solvent to a wafer and prebaking to remove the solvent, but some light absorbers may precipitate during storage or sublimate during prebaking. There is a problem in that the density decreases and the resist performance varies.

<Problems to be Solved by the Invention> The present inventors have made extensive studies to overcome the drawbacks of the above-mentioned prior art, and as a result, have completed the present invention.

That is, an object of the present invention is to eliminate the drawbacks of the prior art, to form a high-resolution pattern on a high-reflectance substrate that is free from halation and notching, and is stable against pre-baking. The object of the present invention is to provide a highly sensitive resist composition in which sensitivity decreases little due to addition.

Another object of the present invention is to ensure that each component in the resist composition has good compatibility, and that the light absorbing agent is finely divided so that it does not precipitate during storage (in the resist composition and in the resist composition film after coating and prebaking). An object of the present invention is to provide a resist composition for processing.

<Means for Solving the Problem> As a result of intensive studies, the present inventors have developed a light absorbing agent of the general formula (I
) It was discovered that the drawbacks of the prior art could be solved all at once by using the compound, and the present invention was completed.

That is, the present invention relates to the general formula H) (wherein R+ , Rz , Rs each independently represent hydrogen,
Represents an optionally substituted alkyl group or halogen atom. χ
, Y each independently represents a cyano group, -C00R, -CO
NHR*, R represents an alkyl group, and Ro represents hydrogen or an aryl group. ) is a resist composition characterized by containing the compound.

The compound represented by general (1) of the present invention is (in the formula R+
, Ri, and R3 are the same as above. ) and the general formula (III>) The condensation reaction is carried out using an inert organic solvent, such as ethanol,
It is carried out using n-propatol, toluene, benzene, chlorobenzene, chloroform, dimethylpolamide, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, acetonitrile, acetic anhydride, or the like.

The compound represented by the general formula (I) and the compound represented by the general formula (I)
The compounds of V) are mixed in said inert organic solvent, a catalyst is added, in particular an organic base such as piperidine, pyridine, triethylamine or a mixture of piperidine and glacial acetic acid, and the mixture is heated at a temperature of 0 to 100° C., preferably 20~80℃
The reaction is carried out for 0.1 to 20 hours, preferably for 0.5 to 10 hours. Then, by distilling off the solvent from the reaction mixture,
- A coarse cake of the compound of the invention is obtained, denoted by Funatsuri N). The crude cake can be purified by recrystallization from an appropriate solvent.

Examples of the general compound (I) include the following compounds, but the present invention is not limited thereto, and two or more of these compounds can be used in combination.

The resist composition containing the compound of general formula (1) in the present invention can be used as a negative resist composition and a positive resist composition, but is preferably used as a positive resist composition. The positive resist composition preferably contains an alkali-soluble resin and a 1,2-quinonediazide compound, and among them, a novolak resin obtained by addition-condensation reaction of phenols and formaldehyde and a 1,2-quinonediazide compound. It is preferable to do so.

Examples of the phenolic compounds used here include:
Phenol, 0-cresol, m-cresol, p-cresol, 3,5-xylenol 2.5-xylenol, 2.3-xylenol 2.4-xylenol, 2.6
-xylenol 3.4-xylenol, 2,3.5-)
Limethylphenol, 2-tert-butyl-5-methylphenol, 2-tert-butyl-6-methylphenol, 2-tert-butyl-4-methylphenol, resorcinol and the like can be mentioned. These compounds may be used alone or in combination of two or more, taking into consideration the solubility in an alkaline developer.

Examples of the aldehydes used in this condensation reaction include formalin, paraformaldehyde, acetaldehyde, and glyoxal. Among these, formalin is particularly preferred because it is easily available industrially as a 37% aqueous solution.

As the acid catalyst used in this condensation reaction, organic acids, inorganic acids, divalent metal salts, etc. are used.

Specific examples include oxalic acid, hydrochloric acid, sulfuric acid, perchloric acid, p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, formic acid, zinc acetate, magnesium acetate, and the like. The condensation reaction is usually carried out at 30 to 250°C for 2 to 30 hours. Further, the reaction may be carried out in bulk or an appropriate solvent may be used.

Next, 1 and 2 used in the positive resist composition of the present invention
- The quinonediazide compound is not particularly limited, but for example, 1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, etc. can be mentioned. These esters can be obtained by a known method, for example, by condensing 1,2-naphthoquinonediazide sulfonic acid chloride or benzoquinonediazide sulfonic acid chloride with a compound having a hydroxyl group in the presence of a weak alkali.

Examples of compounds having a hydroxyl group include hydroquinone, resorcinol, phloroglycin, 214-
Dihydroxybenzophenone, 2°3.4-)lihydroxybenzophenone, 2.34.4'-tetrahydroxybenzophenone, 2, 2', 4. 4'
-tetrahydroxybenzophenone, bis(p-hydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)methane, bis(2,3,4-)dihydroxyphenyl)methane, 2,2-bis<p-hydroxyphenyl) Examples include propane, 2,2-bis(2,4-dihydroquinphenyl)propane, 2,2-bis(2,3°4-trihydroxyphenyl)propane, and oxyflavans. Among them, the 1,2-quinonediazide compound represents 2,3,4,4'-tetrahydroxybenzophenone or oxyflavans. A compound of 1,2-naphthoquinonediazide-5-sulfonic acid ester in which an average of two or more hydroxyl groups is esterified is preferably used. These 1,2-quinonediazide compounds may be used alone or in combination of two or more.

The amount of the compound represented by general (1) in the resist composition of the present invention is usually 0.1 to 20%, more preferably 0.2 to 10%, based on the solid content of the resist composition.
It is. - The amount of the compound represented by formula (I) used is 0.
When the content is 1 to 20%, the resist composition has excellent antihalation effects and exhibits good profile and sensitivity. Furthermore, in the composition of the present invention, in addition to the compound of the present invention, 1
Seeds or two or more other compounds can also be used together (Kano) qRsRs (However, in the formula, q represents a number from 0 to 4, r represents a number from 1 to 5, and q+r represents 2 or more. is.R4,R
s s L s is a hydrogen atom, an alkyl group, an alkenyl group, a cyclohexyl group, or the exposure wavelength of the ally resist composition is g-line (435 nm), i-line (365T1m),
), among which i-line (365 nm) is particularly preferred.

Among these compounds of the present invention, particularly 550 nm or less, more preferably 300 to 450 nm.

More preferably, a compound having maximum absorption for light in a region of 300 to 4001 m is preferably used.

<Effects of the Invention> According to the present invention, the drawbacks of the prior art are eliminated at once, and high-resolution patterns without halation or notching can be stably produced even on high-reflectance substrates without reducing productivity. Its industrial utility value is immeasurable, such as being able to form

<Examples> The present invention will be specifically explained below using synthesis examples and examples, but the present invention is not limited thereto.

Synthesis Example 1 0.66 g of the compound represented by the following formula (1) was added to 100 ml of benzene.
! 22-25℃ and add 0.1d of piperidine.
The mixture was stirred for 30 minutes. Benzene was distilled off from this mixture to obtain a crude cake. Recrystallized from n-hexane to obtain a purified cake of the compound represented by the following formula (3) 1.28
g was obtained.

Melting point: 93.5-95°C Synthesis Example 2 1.12 g of the compound represented by the above formula (1), 1.12 g of the compound represented by the following formula (), and 1.13 g of the compound represented by the following formula (2) The mixture was mixed in 100 ml of benzene, 0.1 d of piperidine was added, and the mixture was stirred at 22 to 25°C for 30 minutes. Benzene was distilled off from this mixture to obtain a crude cake. n-hexane, ethyl alcohol Recrystallization was performed from a 1 part 1 mixed solvent to obtain 1.69 g of a purified cake of the compound represented by the following formula (5).

It was done.

Melting point +106.5-108°C Melting point 292-93°C Synthesis example 3 Formula (6) below Examples 1 to 3 and comparative example 1 Examples 1 to 3 Cresol Tuvorac resin (polystyrene equivalent weight average molecular weight by G P C is 9600) 15 parts and 1゜2
- 1.26 g of the compound represented by naphthoquinonediazide-5-sulfonic acid chloride and the compound 1 represented by the above formula (4)
．． 13 g to ioo ml of benzene! Mix in a bowl and add 0.1 ml of piperidine! was added and stirred at 22-25°C for 1 hour. Benzene was distilled off from this mixture to obtain a crude cake. Recrystallization from n-hexane yielded 1.72 g of a purified cake of the compound represented by the following formula (7) CH3CH
.

A resist solution was prepared by dissolving 4 parts of the condensate (on average 2.4 hydroxyl groups are esterified) and the compounds of Synthesis Examples 1 to 3 (the number of parts shown in Table 2) in ethyl cellosolve acetate.

This resist composition was spin-coated on a 4-inch silicon wafer with an aluminum film to a thickness of 1.8 μm using a spinner, and prebaked on a hot plate at 100° C. for 1 minute. This is a reduction projection exposure group that changes the exposure amount step by step through a test reticle! (iX light wavelength 1 line (36
5 nm). This was developed using 5OPD (trade name, manufactured by Sumitomo Chemical Co., Ltd., positive type developer) using an automatic developing machine at 23° C. for 60 seconds by the static paddle method.

The relative sensitivity in Table 2 is the ratio of the resist composition of Comparative Example 1 to the exposure amount. The absorbance ratio is the ratio to the absorbance of the resist composition of Comparative Example 1 at 365 nm. Further, the antihalation effect was evaluated by the method shown below.

[Evaluation method of anti-halation effect]

1. Preparation of step substrate for evaluation A step pattern having the shape shown in FIG. 1 was prepared by photolithography, etching, and aluminum sputtering on a silicon substrate having a 1 μm thick 5iCh film.

Typical pattern size is a=4μmSb=2pm, c
=1 μm, d=1 μm.

2. Evaluation of anti-halation effect A resist film with a thickness of 1.8 μm was formed by a spin code method on the step substrate with high reflectance produced by the above method.

Exposure and development are performed so that a resist line with a line width (X) of 1.2 μm in a portion without a step is formed across the central recess of the step pattern shown in FIG. 1. (Refer to Figure 2) Reduction rate of the resist line width (g) at the center of the step recess after exposure and development (3) If the amount of decrease in line width is within 10%, it is determined that the tulsion prevention effect (excellent) is achieved. , 11-20
% (good) and 21% or more (bad) Comparative Example 1 A resist composition was prepared, exposed, and developed in the same manner as in Example 1 except that no light absorber was added. When the halation prevention effect was evaluated using the same method as in Example 1, Table-
The results shown in 2 were obtained.

As shown in Table 2, in the examples, patterns could be formed with high sensitivity. The formed pattern was sharply resolved, and there was no notching due to reflected light from the side surfaces of the pattern, indicating that the pattern was excellent in preventing halation from the aluminum surface.

On the other hand, the resist compositions of comparative examples were insufficient in terms of sensitivity or antihalation effect.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the shape of a step pattern for evaluation. FIG. 2 is a diagram showing the resist composition applied, exposed, and developed. Figure 1 Tosu 11 Figure ÷m-X -+

Claims (3)

[Claims] (1) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1, R_2, and R_3 each independently represent hydrogen,
Represents an optionally substituted alkyl group or halogen atom. X and Y each independently represent a cyano group, -COOR, -C
ONHR', R represents an alkyl group, and R' represents hydrogen or an aryl group. ) A resist composition characterized by containing the compound (2) The resist composition according to claim 1, comprising an alkali-soluble resin and a 1,2-quinonediazide compound. (3) An i-line resist composition containing a compound represented by general formula (I).