US Patent 11976363 Purge ring for pedestal assembly

Pedestal assemblies, purge rings for pedestal assemblies, and processing methods for increasing residence time of an edge purge gas in heated pedestal assemblies are described. Purge rings have an inner diameter face and an outer diameter face defining a thickness of the purge ring, a top surface and a bottom surface defining a height of the purge ring, and a thermal expansion feature. Purge rings comprise a plurality of apertures extending through the thickness and aligned circumferentially with a plurality of circumferentially spaced purge outlets in a substrate support.