JPH01188684A - Evacuation device for chemical dry etching - Google Patents

Abstract

PURPOSE:To control the formation of corrosive material in a cooling trap and to stabilize the performance of an evacuation system by providing the line of a preprocess evacuation system for evacuating a device other than the cooling trap and the line of a process evacuation system in parallel. CONSTITUTION:A substrate 11 to be subjected to chemical dry etching is set in a vacuum vessel 1. A main valve 2a and an auxiliary valve 6 are closed, and a main valve 2b is opened to roughly evacuate the vessel 1 to a specified pressure by the preprocess evacuation line and to remove the atmosphere having a high content of moisture. The process evacuation line consisting of a booster pump 4, an oil rotary pump 7a, the cooling trap 3 for collecting reaction products, a powder trap 5, the main valve 2a, and the auxiliary valve 6 is then evacuated to an appropriate pressure, and the above-mentioned etching is carried out. The formation of corrosive material by the reaction of the reaction product adsorbed in the cooling trap 3 with moisture can be controlled by this constitution, hence corrosion in the evacuation device is prevented, and the performance of the evacuation system can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum evacuation system for chemical dry etching of tantalum using a reactive gas.

[Conventional technology]

A conventional vacuum evacuation device for chemical dry etching of tantalum has a booster pump 4 as shown in FIG.
, an oil rotary pump 7a, and a cooling trap 3 for capturing reaction products generated in the chemical dry etching process upstream of the booster pump 4. Vacuum is maintained before and during the process by opening and closing the main valve 2a. Exhaust air was being carried out.

In the chemical dry etching process, a fluorine-based gas is dissociated in a plasma reactor, and tantalum fluoride is formed by a chemical reaction between the generated fluorine radicals and tantalum, which is a material to be etched, formed on the substrate 11. This is done by incorporating tantalum. The generated tantalum fluoride is evacuated by a vacuum pump. Exhausted tantalum fluoride tends to become powder if it accumulates in the exhaust system. Since this powder mixes into the lubricating oil of the oil rotary pump 7a and accelerates the deterioration of the lubricating oil, the cooling trap 3
The tantalum fluoride was captured.

[Invention or problem to be solved]

However, in the above-mentioned conventional technology, in the vacuum evacuation step before the process in the vacuum chamber 1, water vapor contained in the atmosphere and the vacuum chamber 1 A large amount of water adsorbs to the inner vessel wall and becomes a swimsuit. Therefore, hydrofluoric acid, a corrosive substance produced by the reaction between tantalum fluoride trapped on the trap surface and frozen water, may accelerate corrosion within the vacuum pumping system and may be used during equipment maintenance. There was a problem in that it posed a danger to workers. In addition, the produced hydrofluoric acid has a high saturated vapor pressure, so it easily vaporizes in the exhaust system, making the exhaust performance of the exhaust system unstable and affecting the quality of the esodizing process. Ta.

The present invention is intended to solve these problems, and its purpose is to provide a vacuum evacuation device that suppresses the production of corrosive substances such as hydrofluoric acid produced in cooling traps. There is a particular thing.

[Means to solve the problem]

The vacuum evacuation apparatus for chemical dry etching of tantalum of the present invention is a vacuum evacuation apparatus having a cooling trap for trapping reaction products generated by chemical dry etching using a reactive gas, in which evacuation is performed while avoiding the cooling trap. The present invention is characterized in that an exhaust route is provided for a pre-process exhaust system that performs evacuation and a process exhaust system that performs vacuum evacuation during the etching process.

[Effect]

According to the above configuration of the present invention, in the vacuum evacuation process performed before the process in the vacuum chamber, the pre-process exhaust system removes water vapor present in the atmosphere and moisture adsorbed on the walls of the vacuum chamber. By exhausting the water using a cooling trap, it is possible to sufficiently remove the water without causing ice formation, thereby suppressing the formation of corrosive substances due to the reaction between already adsorbed reaction products and frozen water.

〔Example〕

EMBODIMENT OF THE INVENTION Below, the detail of the evacuation apparatus of this invention is demonstrated based on the Example which illustrated.

FIG. 1 shows an embodiment of the vacuum evacuation system of the present invention, which includes a vacuum chamber 1 in which a substrate 11 for chemical dry etching is installed, an oil rotary pump 7a and a main valve 2b. A pre-process exhaust system and a main valve 2a used during the chemical tri-etching process.
, a cooling trap 3, a booster pump 4, a powder trap 5, and an oil rotary pump 7a.

After the new substrate 11 is installed, the inside of the vacuum chamber 1 is filled with air containing water vapor. A pre-process vacuum evacuation step in which the atmosphere is roughly pumped to a predetermined pressure is performed by opening the main valve 2b of the pre-process evacuation route and using the oil rotary pump 7b. In this example, after evacuation is performed to a pressure of about IPa, the main valve 2b is closed, the main valve 2a is opened to switch to the process exhaust path, and then the pressure is reduced to 0 IPa.
After evacuating to a certain degree, the chemical tri-etching process described above was performed.

FIG. 2 shows another embodiment of the vacuum evacuation apparatus of the present invention, which includes a vacuum chamber 1 for performing a chemical trietching process, and an oil rotary pump connected from the vacuum chamber 1 via a main valve 2b. 7a, a booster pump 4 used during the chemical dry etching process, an oil rotary pump 7a, a cooling trap 3 for trapping reactive organisms, a powder trap 5, and a main valve 2a. , an auxiliary valve 6, and a process exhaust path. The vacuum evacuation step before the process of roughly evacuation of the air inside the vacuum chamber 1 is performed by opening the main valve 2b with the main valve 2a and the auxiliary pulp 6 closed, and draining the moisture-rich air into the cooling trap 3, The powder is removed through the powder trap 5. Here too, rough evacuation using the pre-process exhaust path was carried out to a pressure of about IPa, and then the chemical dry etching process was performed by switching to the process exhaust path. As a result, the pump exhaust performance became stable and the oil rotary pump's lubrication wells did not deteriorate.

The vacuum pump in the pre-process exhaust path of the present invention is
A vacuum evacuation device equipped not only with a rough vacuum pump but also with a high vacuum pump for main vacuum pumping may be used.

〔Effect of the invention〕

According to the invention described above, in the vacuum evacuation step before the rough evacuation process from the atmosphere after substrate replacement, the atmosphere containing a large amount of moisture does not pass through the cooling trap and is adsorbed to the cooling trap. This has the effect of suppressing the formation of corrosive substances due to the reaction between reaction products and moisture. Therefore, corrosion within the exhaust system and danger to the human body during equipment maintenance can be prevented, and the exhaust performance of the exhaust system can be stabilized. In addition, by reducing the amount of water adsorbed in the cooling trap, the amount of reaction products captured can be increased accordingly, which has the effect of preventing deterioration of the oil rotary pump and lubricating oil and extending the regeneration cycle time of the cooling trap. It also has

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a chemical dry etching vacuum evacuation apparatus according to the present invention. FIG. 2 is a configuration diagram showing an embodiment of the chemical dry etching vacuum evacuation apparatus of the present invention. FIG. 3 is a configuration diagram showing a conventional vacuum evacuation device. 1... Vacuum chambers 2a, 2b... Main valve 3... Cooling trap 4... Booster pump 5... Powder trap 6 - Auxiliary valves 7a, 7b... Oil rotary pump or above Applicant: Seiko Epson Co., Ltd. Company No. 1 (2) 2 M Figure 3

Claims (1)

[Claims] In a vacuum exhaust system having a cooling trap that captures reaction products generated by a tantalum chemical dry etching process using a reactive gas, a pre-process exhaust system that performs vacuum exhaust while avoiding the cooling trap;
A vacuum evacuation apparatus for chemical dry etching, characterized in that the evacuation routes of process evacuation systems for performing evacuation during the chemical etching process are arranged in parallel.