US Patent 7780867 Edge bevel removal of copper from silicon wafers

Chemical etching methods and associated modules for performing the removal of metal from the edge bevel region of a semiconductor wafer are described. The methods and systems apply liquid etchant in a precise manner at the edge bevel region of the wafer, so that the etchant is applied on to the front edge, the side edge and the back edge. The etchant thus does not flow or splatter onto the active circuit region of the wafer. An edge bevel removal embodiment involving that is particularly effective at obviating streaking, narrowing the metal taper and allowing for subsequent chemical mechanical polishing, is disclosed.