THERMAL PROCESSING APPARATUS AND METHOD FOR EVACUATING A PROCESS CHAMBER

摘要

A thermal processing apparatus (100) is provided comprising a process chamber (102) and a vacuum system (104) for evacuating the process chamber. The vacuum system comprises a pump unit (124) in flow communication with the chamber and a valve assembly (126) between the pump unit and the chamber for controlling a mass flow from the chamber to the pump unit. The valve assembly comprises a main vacuum valve (130) and one or more by-pass valves (132). The one or more by-pass valves are connected to a vacuum line (128) via by-pass lines (133) and in parallel flow in relation with the main vacuum valve.