JPH0413144A - 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, optionally substituted alkyl, halogen, or OH; 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-quinonediazideo 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 th 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 made of a quinone diazide photosensitizer and a novolac resin, resist compositions made of a bisazide photosensitizer and a cyclized rubber resin, etc. have been used. There is.

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 the resolution from decreasing, Japanese Patent Publication No. 51-37562 discloses a dye (Oil Yellow [C, I, -1102[
1]) A resist composition containing the following as a light absorbing agent has been proposed. This dramatically reduces the amount of light that passes through the resist layer and reduces the amount of light that goes around to the light-blocking area (
can be done.

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, and to provide a high-reflectance substrate without halation or 7.
Another object of the present invention is to provide a highly sensitive resist composition that is stable even during prebaking, forms a high-resolution pattern, and exhibits little decrease in sensitivity due to the addition of a light absorber.

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 does not precipitate during storage (in the resist composition, in the resist composition film after coating and prebeta). An object of the present invention is to provide a resist composition for processing.

<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 I), the drawbacks of the prior art can be solved all at once, and have completed the present invention.

That is, the present invention provides - formula (1) (wherein R,, R2, R each independently represent hydrogen, an optionally substituted alkyl group, a halogen atom, or a hydroxyl group.
SY is each independently a cyan group, -〇〇OR, -CO
represents NHR', R represents an alkyl group, and R represents hydrogen or an aryl group. ) is a resist composition characterized by containing the compound.

The compound represented by the general formula (1) of the present invention is a compound represented by the general formula (n) (wherein R,, R2, and R are the same as above) and the compound represented by the general formula (III) (wherein X, Y is the same as above.) It can be obtained by condensing the compounds represented by:

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

The compound represented by the above-mentioned formula (II) and the above-mentioned formula (
The compound of III) is 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 20-8
The reaction is carried out at 0°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.

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.

As a positive resist composition, one containing an alkali-soluble resin and a 1,2-quinonediazide compound is preferable, and among them, one containing a novolak resin obtained by addition-condensation reaction of phenols and formaldehyde and a 1,2-quinonediazide compound. is suitable.

Examples of the phenolic compounds used here include Eva,
Phenol, 0-cresol, m-9 resol, p-cresol, 3.5-xylenol 2.5-xylenol, 2.3-xylenol 2.4-xylenol, 2.6
-Xylenol 3.4-xylenol, 2,3.5-trimethylphenol, 2-tert-butyl-5-methylphenol, 2-tert-butyl-6-methylphenol, 2-tert-butyl-4-methylphenol, Examples include resorcinol. 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, inorganic acids, divalent metal salts, etc. are used.

Specific examples include oxalic acid, hydrochloric acid, sulfuric acid, perchloric acid, p-)
Examples include luenesulfonic acid, trichloroacetic acid, phosphoric acid, formic acid, zinc acetate, and magnesium acetate. 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 examples thereof include 1,2-benzoquinonediazide 4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, and 1.2naphthoquinonediazide-5-sulfonic acid ester. It will be done. 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-trihydroxybenzophenone, 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) ) propane, 2,2-bis(2,4-dihydroxyphenyl)propane, 2,2-bis(2,3°4-trihydroxyphenyl)propane, oxyflavans, and the like. Among them, the 1.2-quinonediazide compound is 2.3.4.4'-tetrahydroxybenzophenone or oxyfura (where q represents a number from 0 to 4, and r represents a number from 1 to 5). , q+r is 2
That's all. R=, Rs, and Rs represent a hydrogen atom, an alkyl group, an alkenyl group, a cyclohexyl group, or an aryl group. ) of 1.2-naphthoquinone diazide-5
- Compounds in which an average of two or more hydroxyl groups are esterified with sulfonic acid esters are 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 the general formula (I) used in the resist composition of the present invention is usually 0% based on the solid content of the resist.
．． It is 1 to 20%, more preferably 02 to 10%.

- The amount of the compound represented by formula (1) is 0.1 to 20
%, the resist composition has an excellent antihalation effect and exhibits a good profile and sensitivity. Furthermore, in the composition of the present invention, one or more compounds may be used in addition to the compound of the present invention.
More than one type of other compounds can also be used in combination.

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

Among these compounds of the present invention, particularly 550 nm or less, more preferably 300 to 450 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 0.96 g of the compound represented by the following formula (1) and 1.13 g of the compound represented by the following formula (2) were mixed with benzene 100rrLI! 0.1-l of piperidine was added, and the mixture was stirred at 22-25°C for 1 hour. Benzene was distilled off from this mixture to obtain a crude cake. n-hexane, ethyl alcohol 1:
1. 1.54 g of a purified cake of the compound represented by the following formula (3) was obtained by recrystallization from a mixed solvent.

Melting point: 82-83°C Synthesis Example 2 1.10 g of the compound represented by the following formula (4) and 1.13 g of the compound represented by the above formula (2) were mixed in 100 °C of benzene,
0.1 mff of piperidine was added and stirred at 22-25°C for 30 minutes. Benzene was distilled off from this mixed solution to obtain a crude cake. n-hexane, ethyl alcohol 1
:1 Recrystallization from a mixed solvent results in M! of the compound represented by the following formula (5). 1.62g of cake was obtained.

Melting point = 71-72°C.

λmax: 356 nm [in ethyl alcohol] Examples 1 to 2 and Comparative Example 1 Examples 1 to 2 15 parts of cresol novolac resin (weight average molecular weight calculated as polystyrene by GPC is 9600) and 12-naphthoquinonediazide-5-sulfonic acid CH3CL A resist solution was prepared by dissolving 4 parts of the condensate (in which 2.4 hydroxyl groups are esterified on average) and the compounds of Synthesis Examples 1 and 2 (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 applied to a reduction projection exposure device (fog light wavelength 1 line (365n) by changing the n light amount stepwise through a test reticle.
m). This was developed using 5OPD (trade name, manufactured by Sumitomo Chemical Co., Ltd., positive type developer) by the static paddle method at 23° C. for 60 seconds in an automatic developing machine.

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 3651 m. 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 19E 5iCh film by photophosphorography, etching, and aluminum sputtering. Typical pattern size is a=4μm, b=2μm5
(=1 μm, d=1 μm.

26 Evaluation of Halation Prevention 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 (y) at the center of the step recess after exposure and development
If the decrease amount of the line width with respect to (X) is within 10%, it is determined that the effect of preventing cracking is excellent (excellent), and 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 sharp and clear, and there was no notching due to reflected light from the side surfaces of the pattern, indicating an excellent effect of preventing grainy 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 → Figure ←-1

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, an optionally substituted alkyl group, a halogen atom, or a hydroxyl group. .X and Y each independently represent a cyano group, -COOR,
-CONHR', 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).