Method to remove copper without pattern density effect

摘要

A new method is provided that allows for the application of electropolish for removal of copper and that is independent of pattern density of the removed copper. Electropolish of the copper is first accomplished by reversing current in the H₂SO₄ or H₃PO₄ solution. After identifying the endpoint of the electropolish, chemical etching of the copper in a H₂SO₄ or H₃PO₄ solution is continued, in this manner avoiding effects of high current density introduced by pattern density.