Truncated dummy plate for process furnace

摘要

A truncated dummy plate which is suitable for promoting substantially uniform flow of process gases among all regions on the surface of a substrate to facilitate deposition of a film having uniform thickness on the substrate. The truncated dummy plate has a circular shape with a flat edge provided in the curved edge of the dummy plate. At least two, and preferably, about three or four of the dummy plates are positioned in the sites on a wafer boat which are in relatively close proximity to a gas outlet in a process furnace typically during a LPCVD process carried out in the furnace. The flat or truncated edges of the dummy plates are disposed on the gas inlet side of the process chamber, with the round edges of the dummy plates disposed on the gas outlet side of the process chamber.