Patent ID: 7879183

Claim:
A showerhead configured to provide a purge gas to a front side of a substrate during a backside processing in a processing chamber, wherein the processing chamber includes an injection nozzle disposed in one side of a processing volume and the injection nozzle is configured for injecting a processing gas towards an edge region of the substrate, the showerhead comprising: a body configured to be disposed over the front side of the substrate, wherein the body has: a bottom surface configured to face the front side of the substrate, wherein the bottom surface has an outer circular region, a central region, and a middle region between the outer circular region and the central region, a top surface opposing the bottom surface, a first plurality of holes distributed in the outer circular region and configured to direct the purge gas towards an edge area of the front side of the substrate, a plurality of port region holes distributed in a port region located on a portion of the outer circular region extending radially inward, wherein the port region is on one side of body and aligned with the injection nozzle, each of the first plurality holes and the plurality of port region holes is a through hole with a first opening at the bottom surface of the body and a second opening at the top surface of the body, and no hole is distributed within a substantial portion of the middle region, and a recess surrounded by a side wall extending from the body outside the first plurality of holes.