US Patent 7128821 Electropolishing method for removing particles from wafer surface

An electropolishing method for removing potential device-contaminating particles from a wafer, is disclosed. The method includes immersing the wafer in an electropolishing electrolyte solution and removing defects and particles from the wafer by rotational friction between the wafer and the electrolyte solution in combination with electrolysis. The method is effective in removing particles from via openings of all sizes, including via openings having a width smaller than about 0.2 μm.