US Patent 7282158 Method of processing a workpiece

This invention relates to a method of processing a workpiece in a chamber. Initially a surface of the workpiece is treated by a process which includes supplying a reactive gas to the chamber through a first gas supply and the surface is then further treated using a process gas supplied to the chamber through a second gas supply during the supply of the process gas so that a portion of the process gas flows into the first gas supply from the chamber to mitigate against residual reactive gas entering the chamber during the further treatment step.