| 摘要 |
In a processing chamber that includes a wafer pedestal adapted to heat and cool a wafer during wafer processing, where the wafer is secured to the pedestal with a wafer clamp ring, a yoke having a surface in spaced facing relation with a wafer surface is positioned atop the clamp ring proximate to the wafer. The yoke surface includes a concave circumferential portion that is curved to provide a reflector, for example a parabolic or elliptical reflector, that is positioned having a focal point coincident with the wafer edge. Reflector positioning and spacing relative to the wafer surface encourage reflection of heat radiated from the edge portion of the wafer surface back to the wafer edge to mitigate thermal losses at the wafer edge and improve temperature uniformity across the surface of the wafer.
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