Patent ID: 7708859
Filing Date: 2010-05-04
Classification: C23C,H01J

Abstract:
1. A gas distribution system for supplying gas to a plasma processing chamber including a gas distribution member having inner and outer zones which are flow insulated from each other, the gas distribution system comprising: a first gas passage in fluid communication with a first process gas source, the inner zone of the gas distribution member of the plasma processing chamber and a bypass line; a second gas passage in fluid communication with the first process gas source, the outer zone of the gas distribution member of the plasma processing chamber and the bypass line; a third gas passage in fluid communication with a second process gas source, the inner zone and the by-pass line; a fourth gas passage in fluid communication with the second process gas source, the outer zone and the by-pass line; and a controller connected in control communication to a plurality of fast switching valves that are operably connected to receive signals from the controller to open or close and the controller is configured so that (i) the first process gas is supplied to the inner and outer zones via the first and second gas passages, while the second process gas is supplied to the by-pass line via the third and fourth gas passages, and (ii) to change the flows of the first and second process gases so that the second process gas is supplied to the inner and outer zones via the third and fourth gas passages, while the first process gas is supplied to the by-pass line via the first and second gas passages; and at least one first flow restrictor, at least one second flow restrictor, at least one third flow restrictor and at least one fourth flow restrictor arranged along the first, second, third and fourth gas passages, respectively, the first, second, third and fourth flow restrictors being operable to maintain an approximately constant gas pressure in a region of the first, second, third and fourth gas passages upstream of and proximate the first, second, third and fourth flow restrictors.