A semiconductor device having a structure which can be manufactured with a higher yield includes a local interconnection layer 14 (a first interconnection layer) on a semiconductor substrate 10 and a global interconnection layer 18 (a second interconnection layer) on the local interconnection layer 14. The local interconnection layer 14 and the global interconnection layer 18 include a local interconnection 24 (a first interconnection) and a global interconnection 28 (a second interconnection), respectively, and the global interconnection 28 is thicker than the local interconnection 24. The local interconnection layer 14 and the global interconnection layer 18 also have a dummy interconnection 34 (a first dummy interconnection) and a dummy interconnection 38 (a second dummy interconnection), respectively. The dummy interconnection 34 is narrower than the dummy interconnection 38.