Patent ID: 8052799
Filing Date: 2011-11-08
Classification: H01J,H01L

Abstract:
1. A device fabrication process, comprising: providing an apparatus which includes: injecting a cleaning gas into the chamber via the first inlet; injecting a collecting gas into the chamber via the second inlet; generating an electric field between the cathode surface and the anode surface, wherein the cathode surface is more negatively charged than the anode surface, wherein a first direction is perpendicular to the cathode surface and the wafer surface, and wherein the first direction is perpendicular to a surface normal direction at every spatial point on the anode surface; and ionizing the cleaning gas into a plasma comprising electrons and positive ions, wherein the positive ions are accelerated to the cathode surface by the electric field to etch a top surface of the wafer resulting in a by-product mixture in the chamber, wherein the collecting gas has a property of preventing the by-product mixture from depositing back to the surface of the wafer.