| 摘要 |
Embodiments in accordance with the present invention relate to apparatuses and methods distributing processing gases over a workpiece surface. In accordance with one embodiment of the present invention, process gases are flowed to a surface of a semiconductor wafer through a substantially circular gas distribution showerhead defining a plurality of holes. A first set of holes located at the center of the faceplate, are arranged in a non- concentric manner not exhibiting radial symmetry. This asymmetric arrangement achieves maximum density of holes and gases distributed therefrom. To compensate for nonuniform exposure of the wafer edges to gases flowed from the first hole set, the faceplate periphery defines a second set of holes arranged concentrically and exhibiting radial symmetry. Processing substrates with gases flowed through the first and second sets of holes results in formation of films exhibiting enhanced uniformity across center-to-edge regions.
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