PURPOSE: To prevent flow-in to the treatment chamber side of a duct within an exhaust pipe when a switching valve is closed during evacuation.
CONSTITUTION: In the title device with a treatment chamber 10 of a wafer S, a vacuum pump 15 which is connected to the treatment chamber 10 via an exhaust pipe 13, and a switching valve 14 provided at the exhaust pipe 13, a check valve 20 is provided within the exhaust pipe 13 between the treatment chamber 10 and the switching valve 14. The check valve 20 is constituted by forming a plurality of bars radially in a certain inclination from the side of the treatment chamber 10 toward the switching valve side 14 and the bars are constituted so that gas is discharged toward the side of the switching valve 14 when the switching valve 14 is closed.
KIZAKIHARA TOSHIROU
KATO TAIJI
MOTOHORI ISAO
KORIYAMA HIROHISA
