Local electrochemical deplating of alignment mark regions of semiconductor wafers

摘要

Local electrochemical deplating of alignment mark regions of semiconductor wafers is disclosed. A tank holds an electrolytic solution. A primary cathode submersed within the solution is at least partially insulated therefrom. An electrochemically metal plated semiconductor wafer submersed within the solution acts as an anode, and has alignment mark regions. Extension cathodes submersed within the electrolytic solution are each at least partially insulated, except for a part of a first end and a second end thereof. The first end part is closely positioned over a corresponding alignment mark region, whereas the second end is situated on a corresponding exposed part of the primary cathode. A power source has its positive terminal operatively coupled to the primary cathode and its negative terminal operatively coupled to the wafer. Current from the power source electrochemically deplates the metal substantially from the alignment mark regions, substantially exposing the alignment marks within these regions.