A copper wiring is desirable for a high-speed logic circuit integrated on a semiconductor substrate, and is patterned through a chemical mechanical polishing, wherein polishing particles are brushed away from the major surface of the resultant semiconductor structure by using aqueous ammonia at 0.0001-0.5 weight percent, catholyte or hydrogen-containing water without damage to the copper wiring, and, thereafter, metallic contaminants such as copper is removed by using washer containing decontaminating agent selected from polycarboxylic acid, ammonium salts thereof and polyaminocarboxylic acid also without damage to the copper wiring.