Patent ID: 8418649

Claim:
A composite showerhead electrode assembly for generating plasma in a plasma processing apparatus, comprising: a backing plate comprising top and bottom surfaces with first gas passages therebetween, the bottom surface having bonded and unbonded regions, the first gas passages having outlets in unbonded regions to supply a process gas to an interior of the plasma processing apparatus; an electrode plate having a top surface, a plasma exposed bottom surface, and second gas passages extending therebetween and in fluid communication with the first gas passages, wherein the second gas passages have inlets in unbonded regions of the top surface of the electrode plate; and an elastomeric sheet adhesive joint disposed between mating surfaces at each of the bonded regions which allows movement in a lateral direction of the electrode plate relative to the backing plate during temperature cycling due to mismatch of coefficients of thermal expansion in the electrode plate and the backing plate; wherein (a) the elastomeric sheet adhesive joint comprises an elastomeric sheet adhesive cast or rolled into a pre-form shape; (b) the elastomeric sheet adhesive joint comprises an elastomeric sheet adhesive of die cut pre-form shape; (c) the elastomeric sheet adhesive joint comprises an elastomeric sheet adhesive laser cut, plotter cut and/or water jet cut pre-form shape; and/or (d) one of the mating surfaces comprises a cavity; and wherein the elastomeric sheet adhesive joint comprises a thermally conductive silicone adhesive sheet and wherein at least one portion of the conductive silicone adhesive sheet has a thermal conductivity of 0.5 W/mK to 0.8 W/mK, at least one portion of the conductive silicone adhesive sheet has a thermal conductivity of 0.8 W/mK to 1 W/mK and/or at least one portion of the conductive silicone adhesive sheet has a thermal conductivity of over 1 W/mK.