Patent ID: 8172949

Claim:
A substrate processing apparatus, comprising: a transfer unit for transferring a substrate to be processed between chambers accommodating therein the substrate; at least one vacuum processing unit connected to the transfer unit and including at least one vacuum preparation chamber and at least one vacuum processing chamber, wherein said at least one vacuum preparation chamber is connected to the transfer unit via a gate valve and has a nonreactive gas introducing unit, a corrosive gas evacuation unit and an opening-to-atmosphere unit, and wherein said at least one vacuum processing chamber is configured to perform a process on the substrate loaded therein via the vacuum preparation chamber by using a corrosive gas as a processing gas; and a controller configured to: introduce a nonreactive gas into the vacuum preparation chamber by controlling a gas introduction valve of the nonreactive gas introducing unit before the gate valve is opened for substrate transfer between the vacuum preparation chamber of the vacuum processing unit and the transfer unit; stop introducing the nonreactive gas by controlling the gas introduction valve of the nonreactive gas introducing unit when the controller determines that an inner pressure of the vacuum preparation chamber becomes equal to an atmospheric pressure, start an evacuation process of a corrosive gas in the vacuum preparation chamber by controlling an evacuation valve of the corrosive gas evacuation unit and then open to atmosphere performed by letting the vacuum preparation chamber communicate with an atmosphere by controlling an opening-to-atmosphere valve of the opening-to-atmosphere unit; and open the gate valve after the step of opening to atmosphere.