Showerhead electrode assemblies for plasma processing apparatuses

The showerhead electrode assembly of claim 18, wherein the contact regions comprise spaced apart annular projections on a lower surface of the thermal control plate, the interface members comprising a plurality of annular interface members sized to cover the annular projections, the particle mitigating seal portion bounding the thermally and electrically conductive gasket portion at an outward perimeter and an inward aperture of each interface member.

The showerhead electrode assembly of claim 18, wherein the thermal control plate is of non-anodized aluminum, the thermally and electrically conductive gasket portion of the interface member is a laminate of metal and polymer materials, and the particle mitigating seal portion of the interface member comprise an erosion resistant elastomer or polymer.

The showerhead electrode assembly of claim 18, wherein the showerhead electrode comprises an inner electrode and an outer electrode, and the inner electrode is a circular plate of single crystal silicon and the outer electrode is a ring electrode comprised of a plurality of segments of single crystal silicon.

(canceled)

The showerhead electrode assembly of claim 18, further comprising thermal chokes on an upper surface of the thermal control plate.

The showerhead electrode assembly of claim 18, wherein the interface member is free of silver, nickel and copper, and the contact regions cover about 1% to about 30% of the surface area of the backing plate.

The showerhead electrode assembly of claim 18, wherein the showerhead electrode includes a silicon electrode plate with gas outlets on one side thereof and the opposite side thereof elastomer bonded to a backing plate which is of non-anodized aluminum.

A method of controlling plasma etching in a plasma etching chamber, comprising:

• supplying process gas to the plasma etching chamber through the showerhead electrode assembly of claim 18, the process gas flowing into a gap between the showerhead electrode and a bottom electrode on which a semiconductor substrate is supported;
• and
• etching a semiconductor substrate in the plasma etching chamber by applying RF power to the showerhead electrode and energizing the process gas into a plasma state, wherein the temperature of the showerhead electrode is controlled by the thermal control plate via enhanced thermal conduction through the thermally and electrically conductive gasket portion of the interface members.