Patent ID: 9443753
Filing Date: 2016-09-13
CPC Classification: C23C,H01J,H01L,Y10T

Claim Text:
1. Apparatus for controlling the flow of a gas in a process chamber having a processing volume within the process chamber disposed above a substrate support and a pumping volume within the process chamber disposed below the substrate support, the apparatus comprising: an annular plate coupled to and surrounding the substrate support proximate a level of a substrate support surface of the substrate support, wherein the annular plate extends beneath a position corresponding to a substrate, when disposed on the substrate support, and radially outward toward an inner peripheral surface of the process chamber to define a uniform gap between an outer edge of the annular plate and the inner peripheral surface, wherein the uniform gap provides a uniform flow path from the processing volume to the pumping volume, wherein the annular plate extends radially outward from an inner edge of the annular plate, then up, outward, and down to form a feature configured to mate with a corresponding feature of the substrate support, and then radially outward to the outer edge of the annular plate, wherein the uniform gap sufficiently restricts flow through the uniform flow path to maintain a choked flow condition when flowing a gas vertically between the outer edge of the annular plate and the inner peripheral surface of the process chamber from the processing volume to the pumping volume, and wherein the uniform flow path is the only flow path from the processing volume to the pumping volume.