Patent ID: 7566379

Claim:
An electrode assembly for a plasma processing system, the assembly comprising: an electrode plate comprising: a first surface, a second surface opposing said first surface and having a central surface and a peripheral surface, a plurality of gas injection orifices extending from said first surface to said central surface of said second surface, and a peripheral edge connecting said first surface to said peripheral surface of the second surface; a cylindrical deposition shield extending from said second surface of the electrode plate, said deposition shield comprising a first sidewall surface contiguous with said central surface, a second sidewall surface opposing the first sidewall surface and contiguous with said peripheral surface, and a distal end surface extending radially inward from said first sidewall surface to said second sidewall surface; and a protective coating provided on said central surface, said first sidewall surface, and at least a portion of said distal end surface, said coating comprising yttrium or dysprosium, or a combination thereof, wherein said distal end surface comprises an outer distal end surface extending radially inward from said second sidewall surface, and a protrusion adjacent to said first sidewall surface and protruding from said outer distal end surface, said protective coating being provided on said distal end surface only on said protrusion.