Abstract: A dual exhaust controller for maintaining isolation between the flows of two different gases in a chamber. The controller includes first and second gas input valves connected between respective first and second sources of different gases and a processing chamber. A pump is fluidly connected to the chamber for exhausting gases therefrom and has first and second gas exhaust valves connected to an outlet of the pump. A gas flow control interlocks the signals operating the gas input valves with the states of first and second gas exhaust valves which exhaust the respective first and second gases from the chamber, so that the different gases are exhausted independently.

Abstract: The invention provides an apparatus and method of monitoring a CVD process and providing an alarm signal normally used to terminate the CVD process in response to detecting the simultaneous occurrences of a command to initiate the CVD process, the initiation of the flow of a reactive process gas into the process chamber and the motion of a turret supporting the workpiece.