Patent ID: 7093560

Claim:
A clamping ring configured to be coupled to a chamber structure of a plasma processing chamber, said clamping ring having a plurality of holes for accommodating a plurality of fasteners, said clamping ring comprising: a plurality of flanges disposed around an outer periphery of said clamping ring, adjacent flanges of said plurality of flanges being disposed such that each hole of said plurality of holes that is disposed in between said adjacent flanges is about equidistant from said adjacent flanges, said plurality of flanges being configured to mate with an opening disposed in a bottom chamber wall of said chamber structure, said clamp ring being disposed outside of said plasma processing chamber, said clamping ring and said flanges being dimensioned such that when said plurality of flanges mate with said chamber structure, recesses between adjacent ones of said plurality of flanges form gaps between said clamping ring and said chamber structure, wherein said plurality of fasteners is configured to couple said clamping ring with said bottom chamber wall and an internal lower electrode of said plasma processing chamber.