Patent ID: 7846497

Claim:
A method of controlling gas flow to a processing system that includes a processing chamber coupled to a facility exhaust through a foreline, comprising: flowing a first gas from a first gas source into a manifold having at least a first outlet port, a second outlet port, a third outlet port and a fourth outlet port, wherein the first outlet port is coupled to the foreline through an evacuation path comprising an isolation valve and a purge line, each of the second and third outlet port is connected to the processing chamber through a respective final valve, each of the second and third outlet port is connected to a pre-flow path through a respective by-pass valve, and the pre-flow path comprises: a throttle valve upstream to the purge line; and the purge line upstream to the foreline; flowing a second gas from a second gas source into the manifold; selecting an operational state of valves within the manifold to cause the first and second gases to exit through at least one of the second or third outlet ports while in a processing mode; flowing the first and second gases through at least one of the second or third outlet ports of the manifold into the foreline by-passing the processing chamber through the pre-flow path until a predefine state of the gases within the manifold is obtained, wherein the predefined state is obtained by utilizing the throttle valve to match conditions in the pre-flow path to conditions of the processing chamber; directing the first and second gases exiting the manifold through at least one of the second or third outlet ports into the processing chamber after the predefine state has been obtained; and processing a substrate within the processing chamber.