Patent ID: 8202393

Claim:
A gas distribution system for supplying a gas mixture to a plasma process chamber, comprising: a first valve arrangement connected to upstream ends of a first gas line and a second gas line; a second valve arrangement connected to downstream ends of the first gas line and the second gas line; a first gas distribution outlet line connected between a source of gas supply and upstream ends of both first and second gas lines through the first valve arrangement; and a first chamber inlet line connected between a plasma chamber and to both downstream ends of first and second gas lines through the second valve arrangement; a first evacuation line connected to the first gas line at a location between the first valve arrangement and the second valve arrangement, the first evacuation line being in fluid communication with a vacuum line; a second evacuation line connected to the second gas line at a location between the first valve arrangement and the second valve arrangement, the second evacuation line being in fluid communication with the vacuum line; and a controller configured to actuate the first valve arrangement and second valve arrangement to selectively flow the gas mixture from the gas supply to the plasma process chamber through the first gas line while the second gas line being closed at both upstream and downstream ends is selectively evacuated by the vacuum line; or to selectively flow the gas mixture from the gas supply to the plasma process chamber through the second gas line while the first gas line being closed at both ends is selectively evacuated by the vacuum line.