JPH0413145A - 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 ;the light absorbing agent is represented by formula I in which each of R1 - R3 is independently H, halogen, optionally substituted alkyl, such acetyl, or cyano; R4 is H or alkyl; 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- quinonediazide compound, thus permitting halation and notching on the high- reflective substrate to be prevented, a pattern to be stabilized against prebacking, 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 novolac resin, resist compositions containing a bisazide photosensitizer and a cyclized rubber resin, etc. have been used. It is being

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. Unnecessary areas are exposed to light due to reflection of light on the side surfaces of the step and the step surface, resulting in a problem called notching halation.

In order to improve the above problem and prevent a decrease in resolution, Japanese Patent Publication No. 51-37562 published a dye (Oil Yellow (C1I, -11020
1) A resist composition containing the following as a light absorbing agent has been proposed. 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 drastically reduced and productivity during semiconductor manufacturing is reduced.

In addition, to create a resist film, a resist composition containing a solvent is usually applied to a wafer and the solvent is removed by pre-baking. There is a condition H in which the concentration decreases due to sublimation and variations in resist performance occur.

<Problem H to be Solved by the Invention> The present inventors have completed the present invention as a result of intensive studies to overcome the drawbacks of the above-mentioned prior art.

That is, an object of the present invention is to eliminate the drawbacks of the prior art, and to provide a high-reflectance substrate without halation or notching.
Another object of the present invention is to provide a highly sensitive resist composition that is stable against blibeta, forms a pattern with high resolution, and exhibits little decrease in sensitivity due to the addition of a light absorber.

Another object of the present invention is to provide a resist for microfabrication, in which each component in the resist has good compatibility, and the light absorber does not precipitate during storage (in the resist composition, in the resist composition film after coating and prebaking). An object of the present invention is to provide a resist composition.

Means for Solving the Problems〉 As a result of intensive studies, the present inventors have determined that the general formula (
The inventors have discovered that by using the compound 1), the drawbacks of the prior art can be solved all at once, and have completed the present invention.

That is, the present invention is directed to the general formula (I) (wherein R+, R2, and Rs each independently represent hydrogen, an optionally substituted alkyl group, a halogen atom, an optionally substituted acetyl group, or a cyano group). R4 represents hydrogen or an alkyl group. X and Y each independently represent a piano group, -C
OOR, -CONHR', R is an alkyl group, R
'' represents water or an aryl group.

The compound represented by the general formula (1) of the present invention is a compound represented by the general formula (I[
) A compound represented by R1 (in the formula, R1, R2, and R3 are the same as above) and a compound represented by - Funatsuri (I) (in the formula, X and Y are the same as above) are condensed. can get.

The pre-itE condensation reaction is carried out using an inert organic solvent such as ethanol, n-propanol, toluene, benzene, chlorobenzene, chloroform, dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, sulfolane,
It is carried out using acetonitrile or acetic anhydride.

Mixing the compound represented by the general formula (Ill) and the compound represented by the general formula (III) in the inert organic solvent, and further mixing a catalyst, particularly piperidine, pyridine, triethylamine or piperidine with glacial acetic acid. Add an organic base such as a liquid and heat from 0 to 100°C, preferably from 20 to
The reaction is carried out at 80° C. for 0.1 to 20 hours, preferably 0.5 to 10 hours. Then, by distilling off the solvent from the reaction mixture, a crude cake of the compound of the present invention represented by formula (■) is obtained. The crude cake can be purified by recrystallization from an appropriate solvent.

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

CH3 CH.

C4H! (n) The resist composition containing the compound represented by the general formula (, I) 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. Ru.

As a positive resist composition, one containing an alkali-soluble resin and a 1,2-quinonediazide compound is preferable, and among them, phenols and formua are preferable.

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. These compounds may be used alone or in combination, taking into account their solubility in alkaline developing solutions.
Used in combination of more than one species.

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 or inorganic acids, divalent metal salts, etc. are used.

Specific examples include oxalic acid, hydrochloric acid, sulfuric acid, perchloric acid, p-)
Examples include luenesulfonic acid, trichloroit[%'J:/acid, crushed 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, 2.4-
Dihydroxybenzophenone, 2°3.4-) dihydroxybenzophenone, 2,34.4°-tetrahydroxybenzophenone, 2.2°, 4,4°-tetrahydroxybenzophenone, bis(p-hydroxyphenyl)methane, bis(2 ,4-dihydroxyphenyl)methane, bis(2,3,4-)lihydroxyphenyl)methane, 2,2-bis(p-hydroxyphenyl)propane, 2,2-bis(2,4-dihydroxyphenyl)propane , 2,2-bis(2,3°4-trihydroxyphenyl)furopane, oxyflavans, and the like. Among them, 1.2-quinonediazide compound is 2.3.
4.4 = -tetrahydroxybenzophenone or oxyfura (in the formula, q represents a number from 0 to 4, r represents a number from 1 to 5, and q+r is 2 or more. R = , Rs , Rg is a hydrogen atom, an alkyl group,
Represents an alkenyl group, a cyclohexyl group or an aryl group. ) 1,2-naphthoquinonediazide-5-sulfonic acid ester, in which an average of two or more hydroxyl groups are esterified, is preferably used. These 1, 2-
The quinonediazide compounds may be used alone or in combination of two or more.

The amount of the compound represented by general formula (I) used 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, one or more other compounds can be used in combination with the compound of the present invention.

The exposure wavelength of the resist composition is g-line (435 nm).
, i-line (・365 nm), etc., but especially i-line (
365 nm) is preferred.

Among these compounds of the present invention, particularly 550 nm or less, more preferably 300 to 45 Q nm.

More preferably, a compound having a maximum absorption of light in a region of 300 to 400 nm 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 The following formula (1) 0.95 g of the compound represented by the following formula (2) was stirred.

Benzene was distilled off from this mixture to obtain a crude cake. Recrystallization was performed from a 1 part 1 mixed solvent of n-hexane and ethyl alcohol to obtain 1.52 g of a purified cake of the compound represented by the following formula (3).

Melting point: 136 to 137.5°C Example 1 and Comparative Example 1 Example 1 15 parts of cresol novolac resin (weight average molecular weight in terms of luphostyrene by GPC: 9600) and 12-naphthoquinonediazide-5-sulfonic acid CH,CH.

A resist solution was prepared by dissolving 4 parts of the condensate (an average of 2.4 hydroxyl groups are esterified) and 0.12 ff of the compound of Synthesis Example 1 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. The exposure amount is changed stepwise through a test reticle using a reduction projection exposure device (exposure wavelength i-line (365n).
m). 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 harayon prevention effect]

1. Preparation of step substrate for evaluation A step pattern having the shape shown in FIG. 1 was prepared on a silicon substrate having a 1 μm thick Sin film by photophosphorography, etching, and aluminum sputtering. Typical pattern sizes are a=4μm, b=2μm, c=
1 μm5d=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. Crossing the central concave part of the step pattern shown in Figure 1,
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. (See Figure 2) Resist line width at the center of the step recess after exposure and development (g)
Reduction rate for (X) If the amount of decrease in line width is within 10%, it is determined that the halation prevention effect (excellent) is 11 to 2.
0% is considered (good), and 21% or more is considered (bad).

Comparative Example 1 A resist composition was prepared, exposed, and developed in the same manner as in Example 1 except that no light absorbing agent was added.

When the antihalation effect was evaluated using the same method as in Example 1, the results shown in Table 2 were obtained.

As shown in Table 2, in the examples, patterns could be formed with high sensitivity. It was found that the formed pattern was clearly 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 DESCRIPTION OF THE 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 H issue To-1→

Claims (2)

[Claims] (1) General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1, R_2, R_3 are each independently hydrogen, an optionally substituted alkyl group, a halogen atom, a substituted R_4 represents hydrogen or an alkyl group. X and Y each independently represent a cyano group,
-COOR, -CONHR', R is an alkyl group,
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. An i-line resist composition characterized by: