The semiconductor device comprises on a semiconductor substrate an insulating structure formed of a plurality of insulating films; an interconnection structure buried in the insulating structure and formed of a plurality of conducting layers; and a plurality of dummy patterns formed of the same conducting layer as the conducting layers forming the interconnection structure and buried in a surface side of the respective insulating films, and the dummy patterns near the interconnection structure are connected with each other through via portions. Thus, the insulating structure near the interconnection structure are reinforced, and the generation of cracks and peelings in the interfaces between the insulating films or in the inter-layer insulating films due to mechanical stresses or thermal stresses can be prevented.