Plating by creating a differential between additives disposed on a surface portion and a cavity portion of a workpiece
AssigneeNovellus Systems, Inc.
InventorBulent Basol
Life of this patent
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Abstract
The present invention relates to methods for plating a conductive material on a substrate surface in a highly desirable manner. The invention removes at least one additive adsorbed on the top portion of the workpiece more than at least one additive disposed on a cavity portion, thereby allowing plating of the conductive material take place before the additive fully re-adsorbs onto the top portion and causing greater plating of the cavity portion relative to the top portion.
Claims29
A method of plating a conductor on a conductive top surface of a workpiece disposed in an electrolyte, the conductive top surface of the workpiece including a top portion and a cavity portion, and having a least one additive adsorbed thereon, the method comprising:
- creating an electric field between an anode and the top surface of the workpiece and allowing plating of the top surface to occur;
- establishing relative motion during plating between the workpiece and a movable mask having an open area larger than the cavity portion, wherein the mask is disposed in proximity to the top surface of the workpiece between the anode and the workpiece;
- wherein the relative motion causes repeated sweepings of a first portion of the at least one additive adsorbed on the top portion of the workpiece, thereby reducing an amount of the first portion of the additive adsorbed on the top portion for a period of time;
- and
- wherein the relative motion exposes an area of the top surface of the workpiece to electrolyte and plating current through the open area for less than two seconds between sweepings.
Dependencies are inferred from the claim text.