A semiconductor device having a multi-layered wiring structure containing a copper layer, comprises a first insulating film formed over a semiconductor substrate, a first copper pattern buried in the first insulating film, a cap layer formed on the first copper pattern and the first insulating film and made of a substance a portion of which formed on the first copper pattern has a smaller electrical resistance value than a portion formed on the first insulating film, second insulating films formed on the cap layer, and a second copper pattern buried in a hole or a trench, which is formed in the second insulating films on the first copper pattern; and connected electrically to the first copper pattern via the cap layer.