摘要 |
Embodiments of the present invention generally provide apparatus and methods for introducing process gases into a processing chamber at a plurality of locations. In one embodiment, a central region of a showerhead and corner regions of a showerhead are fed process gases from a central gas source with a first mass flow controller regulating the flow in the central region and a second mass flow controller regulating the flow in the corner regions. In another embodiment, a central region of a showerhead is fed process gases from a first gas source and corner regions of the showerhead are fed process gases from a second gas source. In another embodiment, a central region of a showerhead is fed process gases from a first gas source and each corner region of the showerhead is fed process gases from a separate gas source. By separately feeding process gases to different regions of the showerhead, the ratio and flow of process gases through the showerhead may be controlled to provide improved uniformity across the surface of a substrate.
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