Patent ID: 8317968

Claim:
A showerhead electrode assembly, comprising: a showerhead electrode adapted to be mounted below a temperature controlled top wall in an interior of a vacuum chamber and powered by radio frequency (RF) energy; a radio frequency (RF) distribution member attached to the showerhead electrode, wherein the RF distribution member includes a first portion adapted to extend axially into an opening in the temperature controlled top wall of the vacuum chamber, and the RF distribution member including a second portion extending laterally over the showerhead electrode, and providing a RF path to multiple contact points across the showerhead electrode, wherein the multiple contact points provide laterally spaced thermal paths extending axially between upper and lower surfaces of the second portion and wherein the RF distribution member includes first and second axially extending gas passages operable to supply process gas to discrete central and annular plenums between the backside of the showerhead electrode and the RF distribution member, wherein the first axially extending gas passage is adapted to connect a first gas supply to the central plenum and the second axially extending gas passage is adapted to connect a second gas supply to the annular plenum; and a thermal path member attached to the RF distribution member and adapted to provide at least a portion of a thermal path between the top wall of the vacuum chamber and the second portion of the RF distribution member to the showerhead electrode; wherein the temperature controlled top wall, in combination with the thermal path member, is adapted to maintain a temperature of the showerhead electrode within a predetermined temperature range.