| abstract |
The method and gas flow control assembly are configured to deliver a gas to the processing chamber zone at a desired flow ratio. In some embodiments, the assembly includes one or more MFCs and a back pressure controller (BPC). The assembly includes a controller, a process gas supply, a distribution manifold, a pressure sensor coupled to the distribution manifold and configured to sense the back pressure of the manifold, a processing chamber, a connection between the distribution manifold, and the processing chamber One or more mass flow controllers that control the flow of gas therebetween, and a back pressure controller that is provided to the one or more mass flow controllers in a parallel fluid relationship, wherein precise flow ratio control is achieved. Other embodiments include an upstream pressure controller configured to control the flow of carrier gas to control back pressure. Further methods and components are described for the proportion of gas flow in the control zone, as in other aspects. |