JPS62123451A - Negative type radiation sensitive resist material - Google Patents

Abstract

PURPOSE:To obtain the titled material having a high resolution and a less tendency for falling a minute pattern to a side way by incorporating a halogenated cresol-formaldehyde novolak resin substd. with a specific sulfonyl group to a photoresist. CONSTITUTION:As the resist material, the resin in which the cresolformaldehyde novolak resin shown by formula I is halogenated to obtain the resin shown by formula II, and one or more of phenolic hydroxyl groups contd. in the unit molecule of said resin is substd. with a sulfonyl group shown by formula III, is used. Thus, in formulas I and II, (m) has the following formula, 2<=(m)<=13. In formula II, R1-R13 are each a hydrogen or H atom. As the resist material has a relative low mol.wt. and 4-15 a polymerization degree, and does not swell in the development, the titled material having the high resolution is obtd. And as the change of the pattern to the negative type does not occur by gelatinizing, the tendency for falling the minute pattern to the side way does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resist material for microfabrication used in the manufacture of semiconductor devices and the like, and particularly to a radiation-sensitive negative resist material for use in electron beam and X-ray lithography.

(Prior Art) In recent years, as semiconductor devices and the like have become highly integrated, technical requirements regarding fine pattern formation have become stricter. For example, resist pattern rules are also moving toward submicron dimensions. In electron beam and x6 lithography aimed at forming patterns in the submicron region, it is important that the resist has high sensitivity, high resolution, and high fine cutting ability. For this reason, much research and development is being carried out to improve the performance of resists, but as is well known, it is relatively easy to achieve high sensitivity and high dry etching resistance for negative resists. , there is a problem of insufficient resolution.

We will try to solve this resolution problem. IF As a negative resist for F-rays and X-rays, CM- obtained by chloromethylating narrow-dispersion IPN (impropenylnaphthalene)
IPN (chloromethylated-boly-2-impropenylnaphthalene) is described in the literature (r'l'l' Conductor Circuit Technology No. 27
Symposium Lecture Collection J (December 1984)
p54).

According to this document, this CM-IPN is used as a negative resist, and when an electric f-line is used at an acceleration voltage of 20 KV (
7) Electron beam %D%” = 0.45g C/c
rg'te.

It has been reported that minimum linewidths of 0.1 gm have been resolved.

(Problems to be Solved by the Invention) However, in this CM-IPN resist, when the pattern width is 0.1 to 0.2 gm and patterns with high aspect ratios are adjacent within 0.8 to 1.0 gm, However, there was a problem in that the resist pattern fell sideways during development.

In view of the above-mentioned conventional problems, it is an object of the present invention to be able to form a pattern with a pattern width of 0.1 to 0.27 zm and a high aspect ratio in a submicron space, to have excellent resolution, and to avoid horizontal fall. An object of the present invention is to provide a radiation-sensitive resist material that does not cause radiation.

(Means for Solving the Problems) In order to achieve the object of the present invention, the radiation-sensitive resist material of the present invention is a cresol formaldehyde novolac resin (m corresponds to 2 to 13) with a degree of polymerization of 4 to 15 (m corresponds to 2 to 13).
In the unit molecule of the halogenated gresol formaldehyde noporac resin (formula (II)) obtained by halogenating the formula (I), at least one hydrogen of the phenolic hydroxyl group is a 2-diazonaphthoquinone-5-sulfonyl group. (formula(
III))) is replaced by the characteristic formula (
I) (In the general formula (I), m represents an integer of J such that ?≦m≦13.) Formula (II) (In the general formula ([), R1 to R13 represent a halogen atom f- or a hydrogen atom f- where m represents a positive integer of 2≦m≦13. R1 to RI3 are composed of one selected from halogen atoms of chlorine, bromine, and iodine and a hydrogen atom, and It is sufficient that at least one substituent is a halogen atom in the formula (II It is used to mean "by species."

The reason why the degree of polymerization of the novolak resin used in the resist material of this invention is set to 4 to 15 is that if the molecular weight is relatively low, it will not swell during development and can be used as a high-resolution negative resist. be.

Furthermore, R (hereinafter, R1 to R13 in general formula (n) are collectively referred to as R) is such that at least one R in general formula (II) is a hydrogen atom, and the remaining R is a hydrogen atom. Identical halogen atoms, such as chlorine, bromine.

It can be a type of atom selected from each atom of iodine.

(Function) The negative type 1/cyst material of the present invention has a low molecular weight, so it has high resolution, and since it does not gel, swelling does not occur during development, and therefore, the fine pattern does not fall sideways.

Furthermore, as will be described later, the resist material of the present invention has a sensitivity of D? becomes 3-OJJ-C/cm2, resulting in higher sensitivity than before.

('y: example) Hereinafter, embodiments of the present invention will be described.

In the Examples described below, preferred specific numerical conditions, materials, and other conditions of the present invention will be explained, but these are merely examples, and the present invention does not apply to these embodiments. It should be understood that this is not limited to examples only.

Example Synthesis of Niresist First, cresol nopolac resin (min) i480-18
00, average molecular weight 3950) and 2.5 g of benzoyl peroxide were dissolved in 2.01 carbon tetrachloride and heated at 70°C.
Heat to. 80% as a halogenating agent to the resulting solution.
After adding ml of sulfuryl chloride over 1 hour, the mixture was heated under reflux for 2 hours to cause a reaction.

Next, carbon tetrachloride was distilled off from the obtained reaction product to obtain 90 g of a brown solid (chlorinated novolak resin). The chlorinated novolak resin thus produced has a δ value of 6.0 to 7.5 (benzene ring) and 1.5 to 2 by 'H-NMR.
．． Calculated from the absorption present in 5 (methyl group and methylene group of benzene ring).

In H of formula (II), R was chlorinated at a ratio of 1 out of 10.

90 g of this chlorinated novolac resin and 62 g of 2-diazonaphthoquinone-5-sulfonyl chloride are dissolved in rough 00 m of dioxane. The resulting solution was heated to a temperature of 20~
While maintaining the temperature at 25° C., 40 mjl of triethylamine is added over 30 minutes to obtain a mixed solution.

After stirring this mixed solution for 4 hours to react, the solid matter is removed by discharging, and the obtained filtrate is poured into water for the second episode.

The generated precipitate is collected by filtration, dissolved in 200 mM acetone, and then poured into one volume of methanol to precipitate again. By vacuum drying the precipitate at a temperature of 35° C. for 24 hours, it was possible to obtain 110 g of a resist composition (2-diazonaphthoquinone-5-sulfonylated chlorinated novolak resin). The resist composition thus obtained is the resist material for electron beams and X-rays of the present invention.

Film Formation 1/The cyst material of the present invention is made of 2-ethoxyethyl acetate, 2-ethoxyethyl acetate and other acetate esters, low polar solvents such as benzene, toluene, xylene and other aromatic hydrocarbons, dimethyl Dissolved in formamide and other amides, dioxane and other ethers, alkyl cellosolve acetates and other similar solutions, and spin-coated to produce good skin II! 2 can be formed.

Nagisara 39 mice! The resist obtained in Example ① was dissolved in 2-methoxyethyl acetate at 40% by weight, and by a spin code method,
It was coated on a Si substrate to a thickness of 1.0 pm and dried at a temperature of 60° C. for 30 minutes.

After irradiating the resist of this substrate with electric f-rays at an acceleration voltage of 20 KV while changing the dose (irradiation amount),
Baking was carried out at a temperature of 0°C for 30 minutes.

The volume ratio of isoamyl acetate to cyclohexane is 4/
Developed with a solvent mixed at a ratio of 6:1.

The film thickness remaining after this development was measured. The results are shown in FIG. In this figure, the horizontal axis represents the dose amount, and the vertical axis represents the normalized residual film rate (residual film thickness (residual film ratio) when the initial film thickness is 1).
The remaining film rate is plotted against the logarithm of the dose.

From this experimental result, the sensitivity of Kitaki's resist is D%wo=
It was found to be 3.08LC/crrr'.

Pattern formation: First, the resist of the present invention was dissolved in the same manner as described for film formation, and the resist of the present invention was applied to a thickness of 1.0 gm on the Si substrate j- by spin coating to form a resist film. do.

Next, the resist film was applied with an accelerating voltage of 20 KV and 1
Writing was carried out using an electron beam with a dose of 5 g C/crs2. Thereafter, development was performed using an appropriate developer to obtain a resist pattern.

When the obtained pattern was observed with a scanning electron f-microscope, it was confirmed that lines of 0.13 pm were resolved at a spacing of 0.25 gm. The spectral ratio at this time was 6.

Example ■ This example is an example of a resist composition using N-bromosuccinimide as the halogenating agent and using bromine as the halogen source fR of general formula (II) in the same manner as in the example. . The number of bromines substituted was 1 per 10 R by the same method as in Example I. Furthermore,
2-diazonaphthoquinone-5-sulfonylation was carried out in the same manner as in Example 1, and the sensitivity was determined by the method described in Example I, except that the solvent was isoamyl acetate and cyclohexane in a volume ratio of 4/6. The results are shown in FIG. According to this, D'l; = 3.5 μC/crm2, which is higher than the conventional one, the resolution is the same as in Example I, and the aspect ratio is also 6.

Example ■ 6.0 g of Talesol novolac resin, 0.25 g of benzoyl peroxide, 200 mJ of carbon tetrachloride. Chlorination was carried out in the same manner as in Example I except that sulfuryl chloride and sulfuryl chloride were used and the reflux time was changed to 6 hours to obtain 12.5 g of a brown solid. By this, -・RIO100 of general formula (II)
R was substituted with chlorine source f at a ratio of 0.

Next, 2-diazonaphthoquinone-5-sulfonylation was carried out in the same manner as in the example using 0 g of 2-diazonaphthoquinone-5-sulfonylchloritro, 100 mM of dioxane, 4.0 m of triethylamine, and Q. To,
10.2 g of resist composition was obtained.

In a manner similar to that determined for the resist of Example I, the solvent was adjusted to a volume ratio of isoamyl acetate to cyclohexane of 6.
When the sensitivity was calculated as /4, as shown in Figure 2,
D2=4.3 gclc layer 2, resolution is Example 1
The shape and aspect ratio were 3 to 4.

Example (2) A resist material was obtained in the same manner as in Example (2). However, the amount of sulfuryl chloride was 16.0 ml in the synthesis. As a result, 9.6 g of a resist composition was obtained in which R was substituted with chlorine source F at a ratio of 6 for every 10 R in the general formula (n).

The sensitivity was determined by the same method as in the example procedure, using the solvent as isoamyl acetate and cyclohexane at a volume ratio of 5.574.5, and the D angle = 2.8 C/cla2 (Fig. 2). The ratio was 6. Also, as in Example I, the resolution is 0.1 at a spacing of 0.25 kLm.
It was confirmed that the 3uLm line was resolved.

It should be noted that the present invention is not limited to the embodiments described in L above. In the embodiment described above, halogenation using chlorine and bromine was explained, but halogenation using iodine may also be used. In that case, the halogenating agent used is l-
An iodinating agent such as iodine chloride may be used.

Furthermore, the number of halogenated substituents is 1 per 10 R.
Although the cases where the substituents are substituted in ratios of 1, 6, and 9 are shown, it is clear that similar effects can be obtained with other numbers of substituents.

Further, the degree of polymerization of the Talesol novolak resin used in the synthesis of the radiation-sensitive resist material of the present invention is 4 to 15. In the resist material of the present invention, it is sufficient that at least one phenolic hydroxyl group in the unit molecule is 2-diazonaphthoquinone-5-sulfonylated.

Furthermore, as a result of the 2-diazonaphthoquinone-5-sulfonylation carried out in Examples - ①, approximately 50% of the phenolic hydroxyl groups of the novolac resin were converted to 2-diazonaphthoquinone in each case.
Substituted with diazonaphthoquinone-5-sulfonyl group.

This means that in the phenolic hydroxyl of the halokenated novolanc resin substituted with a 2-diannaphthoquinone-5-sulfonyl group, (after replacing the unesterified phenolic hydroxyl group f with hydrogen, 'I(-NMR
This can be confirmed by measuring.

(Effects of the Invention) As is clear from the above explanation, according to the resist material for electric f- rays and X-rays of +11, 2-diazonaphthoquinone-5- By using a sulfonic acid ester as a resist, a pattern with a pattern width of 0.1 to 0.2 gm and a high aspect ratio can be formed in a fine pattern of submicron spaces by irradiation with f-rays and X-rays. became possible.

Since the resist of this invention is a low-molecular-weight A, it has high resolution, and since the negative conversion is not due to gelation, sideways collapse of the fine pattern does not occur at all.

[Brief explanation of drawings]

FIG. 1 is a sensitivity curve 1χ for explaining an embodiment of the present invention, and FIG. 2 is a sensitivity curve diagram for explaining embodiments (1) to (2) of this invention. Patent Applicant Oki'Tunkirigyo Co., Ltd. 1-Ten [= Yakuhinryugyo Co., Ltd.] 1 day and month's husband's share'+1's joy'LB month's 4 days'
? /Kunsaikon'1 King Map Figure 1

Claims (1)

[Claims] (1) At least one phenolic unit molecule of the halogenated cresol formaldehyde novolak resin (formula (II)) obtained by halogenating the cresol formaldehyde novolak resin (formula (I)) represented by the general formula (I) A radiation-sensitive negative resist material characterized in that hydrogen in a hydroxyl group is replaced with a 2-diazonaphthoquinone-5-sulfonyl group (formula (III)). Formula (I) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ (In general formula (I), m represents a positive integer such as 2≦m≦13.) Formula (II) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ (In general formula (II), R_1 to R_1_3 represent a halogen atom or a hydrogen atom, and m represents a positive integer of 2≦m≦13. R_1 to R_1_3 represent halogen atoms of chlorine, bromine, and iodine. and a hydrogen atom, and at least one substituent in the unit molecule is a halogen atom.) Formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼