US Patent 7056648 Method for isotropic etching of copper

Copper and copper alloys are etched to provide uniform and smooth surface by employing an aqueous composition that comprises an oxidant, a mixture of at least one weak complexant and at least one strong complexant for the copper or copper alloy, and water and has a pH of about 6 to about 12 so as to form an oxidized etch controlling layer and to uniformly remove the copper or copper alloy; and then removing the oxidized etch controlling layer with a non-oxidizing composition. Copper and copper alloy structure, having smooth upper surfaces are also provided.