JPS5954227A - Dry type pattern forming method - Google Patents

Abstract

PURPOSE:To form a desired pattern easily without damaging and deteriorating a resist by generating plasma by using a gas cooled previously when a radiation sensitive resist pattern is formed on the surface of a material to be etched and the pattern is obtained through plasma etching while using the resist pattern as a mask. CONSTITUTION:The resist pattern sensing radiation, such as ultraviolet rays, far ultraviolet rays, electron rays, X-rays, etc. is formed on the surface of the material to be etched, and the desired pattern is obtained through plasma etching while using the resist pattern as the mask. Tetrafluorocarbon gas containing 5% O2 previously cooled at the temperature of dry ice by methanol-dry ice is entered beforehand in a plasma treating chamber at that time. The inside of the treating chamber is evacuated up to 0.6Torr, and the material to be etched is etched. Accordingly, the degeneration of the resist is prevented while the temperature of the surface of the body to be treated is dropped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dry pattern forming method for semiconductor devices, and more specifically, a resist pattern is formed by photo-etching on the surface 6 of an etched object such as a semiconductor substrate. An improvement in the method of forming a rainbow pattern by etching that causes less damage and deterioration of the radiation sensitive/cyst! L7 is related to a dry pattern forming method.

In recent years, as semiconductor devices have become more highly integrated and have higher performance, microfabrication technology has become increasingly popular. It is becoming more and more difficult for people to understand the situation. One of the basic technologies in this fine, IJl, and 1-etching technology is the etching technology (in C, according to the conventional wet etching method, so-called undercup etching) is used to form fine patterns with high precision. There may be limits to the process.
Dry etching methods have been developed and are being put into practical use because they are similar to stomach scolding.

This dry etching method involves applying a high 8-wave electric field to a suitable reaction agent (1) to generate plasma, that is, radicals or ions, and using a radiation-sensitive resist pattern as a mask, this plasma is caused to react with the object to be etched. Therefore, the radiation-sensitive resist pattern must naturally be protected against plasma during processing and printing.

(While I am aware of this, I would like to point out that various types of lithography have been developed and used in ultraviolet 1, far ultraviolet, electron beam, or X-ray lithography. Generally, these materials have insufficient smearability, and in dry etching, damage and deterioration such as thinning of the film occur in many cases, making them unsuitable for use.

In view of these circumstances, the inventors of the present invention have conducted intensive research to develop a dry pattern forming method using plasma etching that causes less damage and deterioration of the radiation-sensitive resist. It was discovered that the purpose could be achieved by cooling the device beforehand, and based on this knowledge, the present invention was completed.

That is, in the present invention, a radiation-sensitive resist pattern is formed on the surface of an object to be etched, and the pattern is formed by etching the object with plasma using the resist pattern as a mask. The present invention provides a dry pattern forming force method characterized by generating plasma using gas.

The object to be etched used in the method of the present invention includes, for example, a silicon substrate, polysilicon on the surface thereof,
Examples include oxide films, nitride films, and metal films such as aluminum.

In the method of the present invention. Radiation Sensitivity L'1: Formation of the cyst pattern is carried out using ultraviolet rays, far ultraviolet rays, electron beams, or X-ray resists, respectively, by well-known phosphorography. As a radiation-sensitive resist for the ox octopus,
Noah used the following: In other words, UV resists include, for example, a mixture of a cyclized rubber and a bisazide compound as an i/ga type, and a mixture of a novolac resin and an orthoquinone compound as a positive resist. -1, negative types such as polygly/zyl methacrylate bonded with cinnamic acid, positive types such as polymethyl methacrylate, polymethyl isopropenyl ketone, etc., and electron beam resists such as - For example, G-types include polygly/zyl methacrylate, positive resists include polymethyl methacrylate, polymethyl isopropenyl ketone, etc., and negative X-ray resists include polydichloropropyl acrylate, etc. Examples of positive types include polymethyl methacrylate.

Examples of the gas for generating plasma used in the method of the present invention include carbon tetrafluoride, 7'tanium trifluoride,
Halocarbons such as ethane hexafluoride, propane hefluoride, carbon tetrachloride, silicon tetrafluoride, silicon hexafluoride, boron trichloride, or these together with oxygen gas, nitrogen gas,
Mixtures with hydrogen gas, helium gas, argon gas, etc. can be used, and these are appropriately selected and used depending on the object to be etched and the etching conditions.

The above-mentioned plasma generating gas used in the method of the present invention (
(It is necessary to cool the gas in advance before introducing it into the plasma processing chamber.) In general, the lower the temperature of the gas introduced into the plasma processing chamber, the slower the etch rate. Therefore, since the Jf44a and deterioration of l/cyst will be low, the plasma generation gas should be introduced into the plasma processing chamber as low as possible to the extent that it does not compare with solid or fd liquid. is desirable.

Conventionally, it was often impossible to form a pattern by dry etching because the plasma properties of the radiation sensitive resist were insufficient, but with the method of the present invention, there is less damage and deterioration of the radiation sensitive resist, and dry etching is possible. Patterns can be easily formed.

Next, the present invention will be explained in detail in Examples.

Example 1 ○DUR-1013 sensitive to light in the far ultraviolet region
(Manufactured by Tokyo Ohka Kogyo ■) In etching polysilicon using a pattern formed as a mask, plasma equipment OAPM-301B (manufactured by Tokyo Ohka Kogyo (2))
/ζ11f7 is cooled in advance to dry ice temperature with methanol-dry ice in the plasma processing chamber of
．． Carbon tetrafluoride gas containing 5)% of carbon atoms was introduced, and etching treatment was carried out under conditions of power of 200 W%, empty space of 0.6 Torr.

For comparison purposes, carbon tetrafluoride gas containing 5 parts of oxygen at room temperature is introduced into the plasma processing chamber.
Perform etching process I in exactly the same manner as above.

As a result, the etching rate of the resist was 700 A/min when the plasma processing gas at room temperature was introduced, but the etching rate of the resist was 400'' A/min when the plasma processing gas cooled to the Tri-ice temperature was introduced. The etching rate of polysilicon was approximately 4500 A/min regardless of whether or not the introduced scum was cooled.

Example: A silicon oxide (Si02) film with a thickness of 1/zm was etched using four photoresists, masked with I-Ga type photoresist 0MR85 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), and used with the same plasma equipment as in Example 1. Into the plasma treatment chamber, hexafluoroethane cooled to l.life'.temperature using methanol-Tri-ice was introduced, and then heated under the following conditions: power, 300W, vacuum degree, 0.6 Torr. I immediately went to C.

However, for comparison, the etching process was carried out in the same manner as above, except that hexafluoroethane gas at room temperature was introduced.

As a result, when introducing hexafluoroethane gas at room temperature,
The resist has changed in quality and it is impossible to achieve the desired result.
The surface temperature of the trench wafer was 170°C, but if ethane hexane gas cooled to dry ice temperature was introduced, deterioration of the resist could be prevented, and the surface temperature of the trench wafer was 170°C. degree (at 140℃)
.

Patent applicant: Tokyo Denshi Kagaku Co., Ltd. Agent Akira Agata

Claims (1)

[Scope of Claims] 1. Forming a radiation-sensitive resist pattern on the surface of the object to be etched, using the resist pattern as a mask (7) etching the object to be etched with plasma. f: Characteristic dry pattern forming method. 2. The radiation-sensitive resist pattern is exposed to ultraviolet rays, deep ultraviolet rays,
The method according to claim 1, which is an electron beam or X-ray resist pattern. 3. Fat H/f = 6 where the gas is cooled to the lowest possible temperature in the temperature range above the solidification or liquefaction temperature.
Range of determining %f The method described in item 1.