Wiring structures, methods of forming wiring structures and methods of manufacturing semiconductor devices

In the wiring structure forming method to form the lower part of the structure on the substrate. An interlayer insulating film on the lower structure. By partially removing the interlayer insulating film to form a via-hole and the dummy via hole. To partially remove the upper portion of the interlayer insulating film to form a trench in communication at the same time as the via-holes and the dummy via hole. To form the first metal film to fill the via-holes and the dummy via hole. First to form a second metal layer filling the trench on the metal film.