| 摘要 |
The present invention provides an apparatus and method for distributing gas to multiple feeds into a chamber 125 to process a substrate 115. In one embodiment, the system 155 includes a process gas injector 190 for introducing process gas into the chamber 125 and a shield assembly 200 having a number of shield bodies 210, 215, adjacent to the process gas injector to reduce deposition of process byproducts thereon. Each shield body 210, 215, has a screen 230 and a metering tube 240 with an array of holes 245 therein to deliver shield gas through the screen. Shield gas is supplied to the metering tubes 240 through a number of flowpaths 255, each having a flow limiter 265 with an orifice 270 sized so that equal flows of shield gas are provided from each of the shield bodies 210, 215. Preferably, the orifices 270 are also sized so that the flow of shield gas through each metering tube 240 is constant, even if the shield gas is supplied from a supply that varies in pressure or flow.
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