Edge bevel removal of copper from silicon wafers
AssigneeNovellus Systems, Inc.
InventorsSteven T. Mayer, Seshasayee Varadarajan, Andrew J. McCutcheon
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Abstract
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 under viscous flow conditions, so that the etchant is applied on to the front edge area and flows over the side edge and onto the back edge in a viscous manner. 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.
Claims27
A method of removing unwanted metal deposited on an edge bevel area of a semiconductor wafer, the method comprising:
- rotating the wafer;
- prerinsing the wafer using deionized water and and acid;
- and
- delivering a stream of liquid etchant onto the edge of the rotating wafer such that the liquid etchant selectively flows over the edge bevel area while in the viscous flow regime,
- wherein the liquid etchant substantially removes unwanted metal selectively from the edge bevel area.
A method of removing unwanted metal deposited on an edge bevel area of a semiconductor wafer, the method comprising:
- rotating the wafer;
- prerinsing the wafer using deionized water and acid;
- and
- delivering a stream of liquid etchant onto the edge of the rotating wafer such that the liquid etchant selectively flows over the edge bevel area to substantially remove unwanted metal selectively from the edge bevel area.
Dependencies are inferred from the claim text.