Technique for removing defects from a layer of metal

Abstract

A technique for polishing an exposed surface of metal on a substrate to remove defects from mechanical working of metals, such as burrs and pigtails resulting from drilling, and defects from plating, such as nodules and depressions, is provided. The substrate has an exposed metal surface such as copper thereon which is to be treated to remove defects. A planarizing or polishing head, preferably a rotating roller, is provided which is continuously rotating with respect to the substrate, with the head in contact with the metal surface on the substrate. A chemical etchant, essentially free of abrasive material, is continuously supplied to the interface between the metal surface and the head. The treating and polishing continues until the defects have been removed or reduced to an acceptable value. In some instances where significant height reduction is required, thus requiring significant metal removal, several passes of the substrate may be required or a device with multiple heads may be used. The polishing head preferably includes a film having a layer of very fine grit embedded therein, such as 5.mu.-15.mu. silicon carbide (SiC).