SUBSTRATE PROCESSING APPARATUS, PURGE GAS CONTROL METHOD, AND VACUUM TRANSFER CHAMBER CLEANING METHOD

A substrate processing apparatus is disclosed. The apparatus comprises a vacuum transfer chamber including a top surface, a bottom surface, and side surfaces between the top and the bottom surfaces, including a first side surface and a second side surface opposite to the first side surface; a transfer robot, disposed in the vacuum transfer chamber, for transfering a substrate; a load lock module connected to the first side surface; a pipe, connected to a purge gas supply source, for supplying a purge gas into the vacuum transfer chamber; one or more gas ports provided in the top surface in the vicinity of the second side surface and connected to the pipe; and one or more exhaust ports, provided in the bottom surface in the vicinity of the first side surface, to which an exhaust pump for exhausting the purge gas supplied into the vacuum transfer chamber is connected.