Tokyo Electron Limited

Kabushiki Kaisha Toshiba

Yasuo Imamura

Yuuichi Mikata

Katsuya Okumura

Reiji Niino

Shinji Miyazaki

Takahiko Moriya

Toshiharu Nishimura

Hideki Lee

Yoshiyuki Fujita

Hitoshi Kato

Makoto Aoki

Makoto Hasegawa

Yoshio Ishikawa

Hiromi Sakima

Hiromitsu Kanbara

After a polysilicon film is formed on a wafer, a cleaning gas containing ClF.sub.3 at 10 to 50 vol % is supplied into a reaction tube and an exhaust pipe system at a flow rate of 3000 to 3500 SCCM, so as to remove a polysilicon-based film deposited on an inner wall surface of the reaction tube, the surface of a member incorporated in the reaction tube, and an inner wall surface of the exhaust pipe system while the film forming process, by etching using ClF.sub.3. The cleaning gas is supplied while the temperature in the reaction tube is maintained at 450.degree. C. or higher, and in a pressure condition set at the maintained temperature such that an etching rate of the polysilicon-based film by the cleaning gas is higher than an etching rate of silicon which is the material of the reaction tube or the member incorporated in the reaction tube.

Method of cleaning reaction tube and exhaustion piping system in heat

An apparatus for etching a WSi film on a wafer by using a plasma of a gas containing a halogen element includes a vacuum process chamber in which upper and lower counter electrodes are provided. An electrostatic chuck is provided on a table at the center of a susceptor or the lower electrode. The wafer is held on the electrostatic chuck. A focus ring surrounding the wafer in a complementary manner is placed on a flange of the susceptor. The temperature of the wafer surface is set to be lower than that of the surface of the focus ring while the plasma is being generated. The focus ring comprises an inner part of amorphous carbon and an outer part of tungsten. While the plasma is being generated, a halide of tungsten generated from the outer part is diffused on the wafer surface, thereby correcting a distribution of the amount of the halide of tungsten on the wafer surface. Thus, the uniformity within the wafer surface of the etching rate and etching anisotropy is enhanced.

Plasma etching apparatus

Prior to formation of a polysilicon film on a wafer, a pre-coat film having a thickness of 1 .mu.m and consisting of polysilicon is formed on the inner wall surface of a reaction tube or the surface of a member incorporated in the reaction tube. A polysilicon film is formed on the wafer at a temperature of 450.degree. C. to 650.degree. C. A cleaning gas containing ClF.sub.3 having a concentration of 10 to 50 vol. % is supplied into the reaction tube at a flow rate to an area of an object be cleaned of 750 to 3,500 SCCM/m.sup.2 to remove a polysilicon film deposited on the inner wall surface of the reaction tube or the surface of the member incorporated in the reaction tube by etching using the ClF.sub.3. In this case, the cleaning gas is supplied while a temperature in the reaction tube is kept at a temperature of 450.degree. C. to 650.degree. C. and in a pressure condition set at the kept temperature such that an etching rate of a polysilicon film by the cleaning gas is higher than an etching rate of quartz constituting the reaction tube or the member incorporated in the reaction tube.

Method of cleaning reaction tube

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Yokohama, Japan

Yasuo Imamura