An apparatus and method for performing uniform gas flow in a processing chamber is provided. In one embodiment, an apparatus is an edge ring that includes an annular body having an annular seal projecting therefrom is provided. The seal is coupled to a side of the annular body opposite a side adapted to seat on the substrate support. In another embodiment, a processing system is provided that includes a chamber body, a lid, a substrate support and a plurality of flow control orifices. The lid is disposed on the chamber body and defining an interior volume therewith. The substrate support is disposed in the interior volume and at least partially defines a processing region with the lid. The flow control orifices are disposed between the substrate support and the lid. The flow control orifices are adapted to control flow of gases exiting the processing region.