Patent ID: 6159298
Filing Date: 2000-12-12
Classification: C23C

Abstract:
A thermal processing system comprising:a single thermal processing unit for successively processing an object to be processed in a hot atmosphere by both a first thermal process which produces a by-product having a property of drifting and not depositing in an exhaust passage even if the passage has a small conductance, and a second thermal process which produces a by-product having a property of adhering to the passage if the passage has a small conductance;said exhaust passage being connected to the thermal processing unit;a first trap provided in the exhaust passage;a valve provided in the exhaust passage downstream of the first trap with respect to a flowing direction of a gas in the exhaust passage;a second trap provided with cooling means and disposed in the exhaust passage downstream of the valve with respect to the flowing direction of the gas in the exhaust passage;means for heating a section of the exhaust passage upstream of said first trap;means for heating the first trap;means for heating the exhaust passage between the first trap and the second trap as well as said valve;all of the heating means being operated to prevent deposition of the by-product and the second trap being cooled to arrest the by-product, while the first thermal process is being carried out; andat least the means for heating a portion of the exhaust passage upstream of the first trap being operated to prevent deposition of the by-product, and the first trap operating to arrest the by-product while said second thermal process is being carried out.