Abstract: In a substrate processing method for processing a substrate by alternately performing a processing gas supply step of supplying a processing gas for processing the substrate into a processing chamber which accommodates the substrate and to which a gas exhaust line is connected and a replacement gas supply step of supplying a replacement gas for replacing an atmosphere in the processing chamber into the processing chamber multiple times, a ballast gas is introduced into the gas exhaust line when the processing gas supply step is performed.

Abstract: A film forming apparatus, which forms a film on a substrate mounted on a stage in a process chamber by supplying a film forming gas to the substrate from a film forming gas supply facing the stage, includes: a first annular body surrounding the stage with a gap interposed between the stage and the first annular body; a second annular body extending downward from an inner peripheral portion of the first annular body; and a third annular body extending from a peripheral portion of the stage such that the third annular body has a flow path defining surface extending along an inner peripheral surface of the second annular body and a lower end surface of the second annular body.

Abstract: In a substrate processing method for processing a substrate by alternately performing a processing gas supply step of supplying a processing gas for processing the substrate into a processing chamber which accommodates the substrate and to which a gas exhaust line is connected and a replacement gas supply step of supplying a replacement gas for replacing an atmosphere in the processing chamber into the processing chamber multiple times, a ballast gas is introduced into the gas exhaust line when the processing gas supply step is performed.