A surface metal wiring structure for a substrate includes one or more functional μbumps formed of a first metal and an electrical test pad formed of a second metal for receiving an electrical test probe and electrically connected to the one or more functional μbumps. The surface metal wiring structure also includes a plurality of sacrificial μbumps formed of the first metal that are electrically connected to the electrical test pads, where the sacrificial μbumps are positioned closer to the electrical test pad than the one or more functional μbumps.