Evacuation and purging method of vacuum chamber for ultra vacuum

PURPOSE: To adsorb an impurity or a contaminated substance efficiently and to discharge it from a chamber by feeding a heated non-reactive gas through the heated chamber. CONSTITUTION: A supply gas is heated to at least 90 deg.C by a heater 2 before entering a vacuum chamber 4. A flow-rate controller 3 may have a gas flow meter for maintaining the specific flow of the heated gas for the chamber 4. The temperature of a gas fed to the vacuum chamber 4 may be monitored by a thermocouple 6. Further, an additional heat is preferably applied to the vacuum chamber 4 by an independent source with a chamber heater 7. The independent heater 7 helps to maintain the gas temperature in the chamber 4 within a range of 90 deg.C to 250 deg.C normally while the non-reactive gas is swept out. The heat in the chamber 4 may be measured by a thermocouple 9 and heat input from the independent heater 7 may be controlled.