Patent ID: 6968630

Claim:
A vacuum processing apparatus, comprising; a cassette hold means for holding a first cassette storing substrates to be processed and a second cassette storing dummy substrates on a substantially horizontal plane, in the atmosphere; a plurality of vacuum processing chambers, having a substrate table on which either one of said substrates or one of said dummy substrates is placed; a transfer chamber connected to said plurality of vacuum processing chambers with gate valves; two lock chambers, having an evacuating device, a gas introduction device and gate valves, for transferring said substrates and said dummy substrates between the atmosphere and said transfer chamber in a vacuum; an atmosphere conveyor for transferring said substrates and said dummy substrates, between (a) said first and second cassettes and (b) said two lock chambers; an evacuating conveyor for transferring said substrates and said dummy substrates, between (a) said two lock chambers and (b) said plurality of vacuum processing chambers; and a control means arranged to control said atmosphere conveyor so as to transfer said substrates between said first cassette and said plurality of vacuum processing chambers through gate valves, and said dummy substrates between said second cassette and said plurality of vacuum processing chambers through gate valves, wherein said control means is arranged to control said atmosphere conveyor and said evacuating conveyor so that said substrates to be processed and said dummy substrates do not coexist inside the same chamber in vacuum.