JPH0756341A - Positive type electron beam resist - Google Patents

Abstract

PURPOSE:To provide an electron beam resist having high sensitivity and high resolution and excellent in adhesion and dry etching resistance. CONSTITUTION:This positive type electron beam resist consists of poly(2- cyanoacrylate) and ketone resin. When this resist is used, a resist pattern having high sensitivity and high resolution and excellent in adhesion and dry etching resistance can be formed and a significant effect of enhancing productivity and quality can be produced in the production of a photomask, LSI or superLSI.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive type electron beam resist having high sensitivity, high resolution, and excellent adhesion and dry etching resistance. More specifically, the present invention relates to a positive type electron beam resist in which a resist pattern for selective etching or selective diffusion in the production of a photomask in the semiconductor industry or the production of a semiconductor device by direct writing is formed, and is widely used in the industry. It is what is done.

[0002]

2. Description of the Related Art Electron beam resists used in electron beam lithography are classified into positive type and negative type. In general, positive type has a better resolution, and positive type is used as pattern miniaturization progresses with higher integration. Has become popular. As a typical example of the positive type electron beam resist, one using polymethylmethacrylate (PMMA) is known, but it has a very high resolution of 0.1 μm but a low sensitivity of 100 μC / cm ² and a low throughput. There is a drawback that. Therefore, many studies have been conducted to obtain a highly sensitive positive electron beam resist. Examples thereof include poly (butene-1-sulfone), poly (2,2,2-trifluoroethyl α-chloroacrylate), poly (hexafluorobutyl methacrylate), poly (alkyl 2-cyanoacrylate) and JP-A-1. A positive electron beam resist made of poly (cyclohexyl 2-cyanoacrylate) represented by -217341 as a raw material can be used.

[0003]

However, among these resists, poly (alkyl 2-cyanoacrylate) and poly (alkyl 2-cyanoacrylate)
A material using a material other than (cyclohexyl 2-cyanoacrylate) has high sensitivity, but has a drawback that it is inferior in dry etching resistance to PMMA. Although the one using poly (alkyl 2-cyanoacrylate) has the same dry etching resistance as PMMA, it has a drawback that compatibility of sensitivity and resolution is not sufficient, and is not at a practically sufficient level. On the other hand, the one using poly (cyclohexyl 2-cyanoacrylate) has the characteristic that the dry etching resistance is considerably higher than PMMA, but the compatibility of sensitivity and resolution is not sufficient, and when used with high sensitivity, the resolution becomes PMMA. It has the disadvantage of being inferior to the comparison.

In order to improve the resolution of poly (cyclohexyl 2-cyanoacrylate), a method using a mixed solvent of three or more components containing methyl cellosolve and at least one soluble solvent and at least one insoluble solvent as a developing solution (JP-A-2- 11
3256), a developing solution containing methyl cellosolve and 2 carbon atoms
Nos. 4 to 4 using a mixed solvent containing an alkyl cellosolve (Japanese Patent Laid-Open No. 2-297553), the sensitivity and resolution are not yet sufficient, the adhesion is insufficient, and the developing time is long. It has the drawback of being unsuitable for spray development.

Further, Japanese Patent Laid-Open No. 55-105244 discloses a poly
As a method of increasing the sensitivity of (alkyl 2-cyanoacrylate), a method of mixing two components, a polymer in the high molecular region and a polymer in the low molecular region, has been proposed, but this method achieves both sensitivity and resolution. It has not been. In addition, since dry etching resistance, heat resistance, and adhesion are also deteriorated, it has not been put to practical use in applications requiring high resolution.

Therefore, there is a strong demand for a positive electron beam resist having high sensitivity, high resolution, excellent adhesiveness and dry etching resistance, capable of short-time development and suitable for spray development.

[0007]

The present inventors have found that high sensitivity,
The present invention has been made to find a method that satisfies the requirements, and continues to earnestly investigate to obtain a positive type electron beam resist having high resolution, excellent adhesion and dry etching resistance, capable of a short development time and suitable for spray development. It was completed. That is, the present invention relates to a positive electron beam resist which is characterized by comprising poly (2-cyanoacrylate) and a ketone resin.

The first component of the resist of the present invention, poly (2
-Cyanoacrylate) [polymer of 2-cyanoacrylate] can be prepared by anionic polymerization or radical polymerization of 2-cyanoacrylate, and is used for polymerization.
As cyanoacrylate, methyl 2-cyanoacrylate, ethyl 2-cyanoacrylate, propyl 2-cyanoacrylate, isopropyl 2-cyanoacrylate, butyl 2-cyanoacrylate, isobutyl 2-cyanoacrylate, sec-butyl 2-cyanoacrylate, tert. -Butyl 2-cyanoacrylate, pentyl 2-cyanoacrylate, hexyl 2-cyanoacrylate, cyclopentyl 2-
Cyanoacrylate, cyclohexyl 2-cyanoacrylate, cycloheptyl 2-cyanoacrylate, cyclooctyl 2-cyanoacrylate, 4-methylcyclohexyl
2-cyanoacrylate, 2-methylcyclohexyl 2-cyanoacrylate, cyclohexyl 2-cyanoacrylate, 2-cyclohexylethyl 2-cyanoacrylate, 2,
2,2-trifluoroethyl 2-cyanoacrylate, 2-ethoxyethyl 2-cyanoacrylate, benzyl 2-cyanoacrylate, 2-phenylethyl 2-cyanoacrylate,
Examples thereof include 3-phenylpropyl 2-cyanoacrylate and 2-phenoxyethyl 2-cyanoacrylate.

Preferred poly (2-cyanoacrylate) for the present invention has a weight average molecular weight of 100,000 to 2,000,000, more preferably 200 to 1,000,000.
If the molecular weight is too large, a solvent with good solubility necessary for applying a thin film may not be present, or a gel may not be formed in the solution so that a uniform thin film may not be obtained. Further, if the molecular weight is too small, the sensitivity is lowered, and it becomes difficult to obtain a uniform thin film having an appropriate thickness, and the effect of the combined use of the second component, a ketone resin, is not observed.

The second component of the resist of the present invention, a ketone resin, is a resin obtained by condensing a ketone and formaldehyde with an alkali catalyst. Examples of the ketone to be used include methyl ethyl ketone, methyl isobutyl ketone, acetophenone, cyclohexanone, methylcyclohexanone and the like, and those using acetophenone and cyclohexanone are particularly preferable. The preferred ketone resin for the present invention has a weight average molecular weight of 10,000 or less, and more preferably 500 to 5,000. When the molecular weight is more than 10,000, the effects of compatibility of sensitivity and resolution and shortening of development time are insufficient, and when the molecular weight is too small, dry etching resistance and heat resistance are deteriorated. Specific examples of the ketone resin include Hirac HK110H, Hirac HK111, and Hirac H.
Commercially available products such as K901 and Hirac 112T (all manufactured by Hitachi Chemical Co., Ltd.) can be mentioned.

The weight ratio of the poly (2-cyanoacrylate) and the ketone resin used together is preferably in the range of 95: 5 to 30:70, more preferably 90:10 to 50:50. If the proportion of the ketone resin is less than 5% by weight, the effects of compatibility of sensitivity and resolution and shortening of the developing time are insufficient, and if it exceeds 70% by weight, the dissolution selectivity of the unexposed area and the exposed area is high. It becomes difficult, and the contrast and the residual film rate decrease, and the heat resistance and the adhesiveness also decrease.

The solvent used when the positive electron beam resist of the present invention is used is, for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, isobutyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol methyl ether. Acetate, ethyl lactate, toluene,
Xylene, 1,2-dichloroethane, etc. are used.

Any developer may be used as long as it can distinguish the exposed portion from the unexposed portion and selectively dissolves the exposed portion. Generally, the polymer mixture, that is, a soluble solvent for the unexposed portion, is used. It is selected from combinations with insoluble solvents. Soluble solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl isoamyl ketone, cyclopentanone, cyclohexanone, 4-methoxy
-4-methyl-2-pentanone, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate, methyl carbitol acetate, Ethyl carbitol acetate, propyl carbitol acetate, butyl carbitol acetate, 3-methyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, butyl formate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, Methyl butyrate,
Ethyl butyrate, ethyl benzoate, ethyl-3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate,
Butyl lactate, dimethyl cellosolve, diethyl cellosolve, tetrahydrofuran, methyl cellosolve, methyl carbitol, ethyl carbitol, propylene glycol monomethyl ether, diacetone alcohol, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, nitromethane, nitroethane, 1-nitropropane, acetonitrile , Toluene, xylene, chloroform, dichloromethane and the like. Further, as the insoluble solvent, methanol, ethanol, 1-propanol,
Examples include isopropanol, 1-butanol, 2-butanol, cyclopentanol, cyclohexanol, ethyl cellosolve, propyl cellosolve, isopropyl cellosolve, butyl cellosolve, butyl carbitol, hexane, heptane, cyclohexane, petroleum ether, water and the like.

[0014]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

Example 1 Poly (cyclohexyl 2-cyanoacrylate) having a weight average molecular weight of 480,000 and a ketone resin (Hirac HK111)
A 6 wt% cyclohexanone solution of the mixture having a weight ratio of 80:20 was prepared and pressure-filtered with a 0.2 μm Teflon membrane filter to obtain a resist solution. 100 parts of this liquid
A glass substrate having a 0 angstrom chromium vapor deposition film was spin-coated at 1000 rpm and prebaked at 120 ° C. for 30 minutes to obtain a uniform thin film of 0.5 μm. Next, this thin film was irradiated with an accelerating voltage of 15 kV and an irradiation dose of 1.
Electron beam exposure with a width of 0.5 μm was performed by changing it stepwise from 0 to 20.0 μC / cm ² . Further, after immersing in ethyl acetate / propyl cellosolve = 15/85 (volume ratio) for 1 minute at 20 ° C., rinsing with isopropanol for 30 seconds 1
When post-baking was performed at 20 ° C. for 10 minutes, a resist pattern having a width of 0.5 μm was obtained at an irradiation dose of 4.0 μC / cm ² . When the obtained resist pattern was observed by SEM, a rectangular pattern having good edge linearity was observed. In addition, CCl ₄ / O ₂ was applied to a 0.5 μm wide resist pattern formed on the chromium vapor deposition film in the same manner.
After the chrome film was dry-etched with, the resist film was stripped with acetone. As a result, a chrome pattern faithful to the resist size and having a small taper was obtained.

Examples 2 to 4 and Comparative Example 1 An acceleration voltage was applied to a 0.5 μm thick resist thin film obtained in the same manner as in Example 1 except that the mixing ratio of poly (cyclohexyl 2-cyanoacrylate) and ketone resin was changed. 15
Electron beam exposure with kV, 0.5μm width, ethyl acetate /
After immersing in propyl cellosolve = 15/85 (volume ratio) for 30 seconds to 1 minute at 20 ° C., 3 times with isopropanol
After rinsing for 0 seconds, post-baking was performed at 120 ° C. for 10 minutes. The above results are summarized in Table 1. The irradiation dose at which a resist pattern having a width of 0.5 μm was obtained varied depending on the ratio of the ketone resin, and the sensitivity was remarkably low in the case of no addition. Further, when the obtained resist pattern was observed by SEM, a rectangular pattern having good edge linearity was observed in the range where the mixture ratio of the ketone resin was 10 to 70% by weight. Table 1 also shows the results when Comparative Example 1 did not use a ketone resin.

[0017]

[Table 1]

Examples 5-6 Ketone resins of different grades in Example 1 (Hirac HK110T (Example 5), Hirac KH901)
(Example 6)) obtained in the same manner from
Accelerating voltage 15kV, 0.5μm on the resist thin film of μm thickness
Electron beam exposure was performed in a width, and the developer was immersed in ethyl acetate / propyl cellosolve = 15/85 (volume ratio) at 20 ° C. for 1 minute. Rinse with isopropanol for 30 seconds 1
Each 4.0μC / cm ² by performing a post-baking for 10 minutes at 20 ° C., the resist pattern of 0.5μm width 5.0μC / cm ² was obtained. When the obtained resist pattern was observed by SEM, a rectangular pattern having good edge linearity was observed. Also, the chromium pattern obtained by dry etching was good.

Examples 7 to 8 A 0.5 μm thick resist thin film obtained in the same manner as in Example 1 was subjected to electron beam exposure at an acceleration voltage of 15 kV and a width of 0.5 μm, and the developing solution was methylisobutylketone / isopropanol = 50. / 50 (volume ratio, Example 7) or propyl acetate / propylene glycol monobutyl ether = 30 /
It changed to 70 (capacity ratio, Example 8) and each was immersed for 1 minute at 20 degreeC. Each 3.0μC / cm ² by performing a post-baking for 10 minutes at 120 ° C. for 30 seconds rinsed with isopropanol, in 6.0μC / cm ² 0.5μ
An m-width resist pattern was obtained. When the obtained resist pattern was observed by SEM, a rectangular pattern having good edge linearity was observed. Also, the chromium pattern obtained by dry etching was good.

Comparative Example 2 A 4.5 wt% cyclohexanone solution of poly (cyclohexyl 2-cyanoacrylate) having a weight average molecular weight of 480,000 was prepared and pressure-filtered with a 0.2 μm Teflon membrane filter to obtain a resist solution. This solution was spun on a glass substrate having a 1000 angstrom chromium vapor deposition film at 900 rpm.
After spin-coating with, the film was pre-baked at 120 ° C. for 30 minutes to obtain a uniform thin film of 0.5 μm. Next, this thin film was irradiated with an accelerating voltage of 15 kV and an irradiation dose of 1.0 to 20.0 μC.
Electron beam exposure with a width of 0.5 μm was carried out by changing stepwise to / cm ² . Further, after immersing in methyl cellosolve / isopropyl cellosolve = 50/50 (volume ratio) for 5 minutes at 20 ° C., rinse with isopropanol for 30 seconds, and 120 ° C.
After post-baking for 10 minutes, the irradiation dose was 3.0.
A resist pattern having a width of 0.5 μm was obtained at μC / cm ² . When the obtained resist pattern was observed by SEM, the linearity of the edge was good, but the pattern was slightly tapered, and peeling of the pattern edge was partially observed. In addition, for the 0.5 μm wide resist pattern formed on the chromium vapor-deposited film in the same manner, CCl
After dry etching of the chromium film with ₄ / O ₂ , the resist film was stripped with acetone. As a result, a chromium pattern having a slightly large taper and a partial thinness was obtained.

Comparative Example 3 A 5 wt% cyclohexanone solution of a mixture of poly (ethyl 2-cyanoacrylate) having a weight average molecular weight of 650,000 and an ethyl cyanoacetate-paraformaldehyde condensate having a weight average molecular weight of 2200 at a weight ratio of 80:20. And make 0.2
A resist solution was obtained by pressure filtration with a μm Teflon membrane filter. This solution was spin-coated at 1000 rpm on a glass substrate having a 1000 angstrom chromium deposited film, and prebaked at 120 ° C. for 30 minutes to obtain a uniform thin film of 0.5 μm. Next, this thin film was irradiated with an accelerating voltage of 15 kV and an irradiation dose of 1.0 to 20.0 μC / cm.
Electron beam exposure with a width of 0.5 μm was carried out by changing it stepwise to ² .
Furthermore, ethyl acetate / methyl isobutyl ketone = 50 /
After soaking in 50 (volume ratio) at 20 ° C for 1 minute, rinsing with isopropanol for 30 seconds and post-baking at 120 ° C for 10 minutes resulted in irradiation of 2.0 µC / cm ^{2 with} 0.5 µm width. A resist pattern was obtained. When the obtained resist pattern was observed by SEM, the edge linearity was slightly bad and a pattern shape with a hem was observed. In addition, 0.5 was similarly formed on the chromium vapor deposition film.
After dry etching of the chromium film with CCl ₄ / O ₂ on the resist pattern with a width of μm, the resist film was stripped with acetone. As a result, a chromium pattern with a smaller taper than the resist size was obtained. It was The above results are summarized in Table 2.

[0022]

[Table 2]

[0023]

According to the present invention, it is possible to form a positive type electron beam resist pattern having high sensitivity, high resolution, and excellent adhesiveness and dry etching resistance by short-time development. Therefore, the present invention is applicable to photomask manufacturing, LSI,
A great effect can be brought about in the improvement of productivity and quality in the manufacture of VLSI.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Okuyama 1-1 Funami-cho, Minato-ku, Nagoya, Aichi Toagosei Chemical Industry Co., Ltd. Nagoya Research Institute (72) Inventor Akira Tamura Taito-ku, Taito-ku, Tokyo 1-5-1 Toppan Printing Co., Ltd. (72) Inventor Shoji Yonezawa 1-5-1 Taito Taito-ku, Tokyo Inside Toppan Printing Co., Ltd.

Claims (1)

[Claims] 1. A positive electron beam resist comprising a poly (2-cyanoacrylate) and a ketone resin.