Abstract: The present invention relates to a method and apparatus for removing particles from substrates undergoing processing in a semiconductor processing system. In the method according to the present invention, semiconductor wafers are placed in a vacuum chamber and gas is injected over the semiconductor wafer to dislodge and remove contaminant particles. The gas is provided by a gas injector affixed to the side of the vacuum chamber opposite the entry point of a wafer. In a preferred embodiment, the gas injector is oriented in the same horizontal plane as the robot arm used to place and remove wafers from the chamber.