JPS63288016A - Manufacture of photomask - Google Patents

Abstract

PURPOSE:To manufacture a submicron photomask in a stable and highly precise manner by a method wherein, using halogenated polystyrene of 2000-20000 in molecular weight as electron beam resist, an exposing operation is conducted using ionized radioactive rays, a developing operation is conducted, and after ultraviolet rays have been projected, dry etching is performed. CONSTITUTION:The ionized radioactive ray resist, consisting of halogenated polystyrene of 2000-20000 in molecular weight is coated uniformly by conducting a spin-coating and the like on the substrate 8 to be processed and formed by providing a chromium deposition film 2 on a substrate 1, and an ionized radioactive ray resist layer 3 is provided by performing a heating and drying treatrment. A pattern is drawn by projecting ionized radioactive rays 4 on the layer 3, it is developed using a developing solution, rinsed with alcohol, a resist pattern 5 is formed, and it is hardened by collectively projecting ultraviolet rays 6. A fine pattern 9 is formed by dry-etching the part to be processed which is exposed from the aperture part of the resist pattern by irradiating gas plasma 7. Then, a photomask 10 is completed by conducting an ashing treatment on the remaining resist 5 using oxygen plasma.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to the production of high-density integrated circuits such as LSIs and VLSIs (: a method for producing photomasks used in the production of high-density integrated circuits such as The present invention relates to a method of manufacturing a photomask having a micron pattern.

[Conventional technology]

In recent years, many photomasks used in the manufacture of semiconductor integrated circuits have been practically manufactured by etching using electron beam lithography. In the production of photomasks using electron beam lithography, electron beam resists include polyglycidyl methacrylate, glycidyl methacrylate-acrylic acid copolymer, chloromethylated polystyrene, polybutene-/-sulfone, poly-α-chlorotrifluoroethyl acrylate, etc. are used,
High-precision products such as 70x reticles and 5x reticles for stepper exposure and master masks for aligner exposure are manufactured.

[Problem that the invention seeks to solve]

However, in recent years, the demand for photomasks with submicron patterns has rapidly increased.However, despite the rapid increase in demand for photomasks with submicron patterns, the electron beam exposure process for photomask manufacturing (2) Currently, there is no one that can stably manufacture micron photomasks.

In other words, negative type electron beam resist has high sensitivity but has poor resolution and is impossible to form a pattern of 1 μm or less, and positive type electron beam resist has higher resolution than negative type but is difficult to manufacture. Due to the narrow tolerance range of conditions and extremely low dry etching resistance, it is virtually impossible to manufacture submicron masks of θ, juWL or less.

There are two problems to be solved by the present invention: to provide a method for manufacturing a photomask that can stably manufacture a highly accurate submicron mask.

[Means for solving problems]

In view of the above-mentioned problems, the present inventor conducted research to develop a method for stably manufacturing highly accurate submicron masks, and as a result of his research, he discovered that an electron beam resist with a molecular weight of
Using halogenated polystyrene of The present invention has been completed based on these findings.

That is, the present invention provides ``a step of forming a resist thin film using ionizing radiation on a substrate to be processed;
A process of irradiating ionizing radiation in a pattern and developing to form a resist pattern, a process of dry etching the exposed area of the substrate to be processed using the resist pattern as a mask, and a process of exposing the resist remaining after dry etching to oxygen plasma. In a method for manufacturing a photomask, the method uses halogenated polystyrene or a derivative thereof with a molecular weight of 000 to 40θ as the ionizing radiation resist, and irradiates it with deep ultraviolet rays after forming a resist pattern. A method for manufacturing a photomask, which comprises dry etching a substrate to be processed after hardening a resist pattern.

Hereinafter, the present invention will be described in detail with reference to the drawings.

First, as shown in FIG. The ionizing radiation resist layer 3 is coated uniformly by a conventional method such as nuvin coating, and subjected to a heat drying process to provide a ionizing radiation resist layer 3 having a thickness of about 0, 0, 0, and 0.

The heat drying process depends on the type of resist, but usually go~/
Approximately 20 to 60 minutes at 0°C is suitable.

Next, as shown in FIG. 1 (bl), the ionizing radiation resist layer J (
: Conventional method (2) Therefore, a pattern is drawn by irradiating ionizing radiation with an ionizing radiation exposure device such as an electron*g optical device, and developed with a developer containing an organic solvent as a main component such as Etelceron Lube.
As shown in FIG. 1 (e1), rinse with alcohol to form a resist pattern!

Next, this resist pattern:
The resist pattern S is cured by irradiating the resist pattern S for one minute (FIG. 1(d)).

Next, as shown in FIG. 1 (1), gas plasma 7 is irradiated to open the opening of the resist pattern using the tactile method (both methods are possible, but the method is better in terms of forming a fine pattern and improving dimensional accuracy). Dry etching is suitable.Etching is easier (=performed with higher precision); secondly, descum processing is preferable.

Finally (2. As shown in FIG. 1(f), the remaining resist S is subjected to an ashing process using oxygen plasma to remove the photomask 1.
0 is completed.

Resist materials that can be used in the present invention include halogenated polystyrene and its derivatives, such as chlorinated polystyrene/, iodinated polystyrene, chloromethylated polystyrene, chlorinated polymedelsterene, and α-methylchloromethylated polystyrene.

etc. are possible.

[For production]

Since the resist used in the present invention has a low molecular weight,
High resolution, only the ionizing radiation irradiation area is selective (
It is estimated that the image is exposed with high accuracy.

Further, there is a large difference in solubility between exposed and unexposed parts of the resist, resulting in good developability.

Furthermore, since it has a Bo9 spray/skeleton, it has high dry etching resistance.

〔Example〕

Example / 700A thickness (=
A 10wL% xylene solution of chloromethylated polystyrene with a molecular weight of too much was applied by spin coating on a chromium mask substrate formed by vapor deposition at 720°C.
A uniform resist M having a thickness of 0.11 μm was obtained by prebaking for 0 minutes. Next, a pattern was drawn by exposing the substrate to an electron beam with a beam diameter of 0.7 S μm and an acceleration voltage of 10 KV (second step) at a dose of 20 μm.
Developed by immersion for 0 seconds and 3θ with Inglobil alcohol.
A resist pattern was obtained by rinsing for seconds.

After irradiating this resist pattern with deep ultraviolet light for S minutes,
Dry etching was performed for g minutes in a plasma consisting of carbon tetrachloride and oxygen with an output of 300 W. After etching, the substrate was placed in oxygen plasma at pressure/Torr and output of 200W for 20 minutes.
After processing for a minute and ashing the resist pattern,
．． A photomask having a chrome pattern consisting of lines and spaces of 2 μm in size was obtained.

Example: On a glass substrate with a thickness of 0,000 mm / on a photomask substrate consisting of a two-layer structure of chromium with an OOA thickness and chromium oxide with a thickness of 200 mm): α-Methylchloromedelated polysprene with a molecular weight of 2000 An ethyl cellosolve solution of 1 covt% was applied by spin coating, and the solution was heated at 30° C.
A uniform resist film having a thickness of θ and jj μm was obtained by prebaking for 1 minute. Next, this 1 beam diameter is 0. /! Patterns were drawn using an electron beam of rμm and acceleration pressure of 10g with a dose of 2Sμ hook. After exposure, this substrate was treated with isoamyl acetate/di-n
-Butyl ether-1I/3 was developed by immersion for 60 seconds, and rinsed with di-n-butyl ether for 30 seconds to obtain a resist pattern.

After irradiating this pattern with dual-speed ultraviolet light for 5 minutes, dry etching was carried out in the same manner as in Example, and the remaining resist was ashed to obtain a photomask having a pattern with a minimum size of 0.3 μm.

〔Effect of the invention〕

As described in detail above, according to the present invention, a submicron photomask, which could not be obtained conventionally, can be manufactured with high precision and in a stable process.

Therefore, the present invention provides a method for manufacturing submicron photomasks for the production of ultra-high density integrated circuits. It is extremely useful for # construction.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(f) are cross-sectional views showing the process of the manufacturing method of the present invention. l・・・・・・・・・Board 2 fists・eases・-Chromium 3・・・・・・・・・Resist f@q・・・・・・
・・・・・・1 Ionizing radiation 3・・・・・・・・・・Exposure area 6・・・・・・・・・・Deep ultraviolet light 71111・1 Gas plasma Patent applicant Dai Nippon Printing Co., Ltd. Agent Patent Attorney Atsumi Konishi Figure 1 Figure 1 Figure 1...Todai 2...Chrome 3...Rebus Shirei 4...Ka Niira N Soul 5...Katsuku Part 6...・・Mizushigai L 7 ・・Gasara Tema

Claims (1)

[Claims] a step of forming an ionizing radiation resist thin film on a substrate to be processed; a step of irradiating the ionizing radiation resist thin film in a pattern with ionizing radiation and developing it to form a resist pattern; and a step of forming a resist pattern using the resist pattern as a mask. In a method for manufacturing a photomask, which includes a step of dry etching a processed substrate region and removing the resist remaining after the dry etching by ashing with oxygen plasma, the ionizing radiation resist has a molecular weight of 2,000 to 2.
A method for producing a photomask using 0,000 halogenated polystyrene or a derivative thereof, and comprising: forming a resist pattern, curing the resist pattern by irradiating it with deep ultraviolet rays, and then dry etching a substrate to be processed.