Patent ID: 8337960

Claim:
A seasoning method for a silicon nitride film-forming apparatus configured to make an electromagnetic wave incident on a processing chamber of the silicon nitride film-forming apparatus from an antenna of a circular ring shape disposed outside the processing chamber through an electromagnetic wave transmissive window provided on the processing chamber and thus to convert a silicon-containing gas and a nitrogen-containing gas supplied into the processing chamber into a plasma state, thereby forming a silicon nitride film on a substrate placed in the processing chamber, characterized by comprising the steps of: supplying a cleaning gas into the processing chamber, and etching the silicon nitride film attached to an inner wall of the processing chamber while converting the cleaning gas into a plasma state; supplying the silicon-containing gas into the processing chamber, and depositing an amorphous silicon film on the inner wall of the processing chamber while converting the silicon-containing gas into a plasma state; supplying the silicon-containing gas into the processing chamber, while supplying the nitrogen-containing gas in a gradually increasing manner up to a predetermined flow rate, and thus depositing, on the amorphous silicon film, a silicon nitride film with the nitrogen content gradually increasing in a thickness direction, while converting the silicon-containing gas and the nitrogen-containing gas into a plasma state; and supplying a rare gas into the processing chamber and maintaining a plasma state of the rare gas until film formation of the silicon nitride film on the substrate is initiated including a period of conveying the substrate to the processing chamber.