A technology for inhibiting the dielectric breakdown occurred in a semiconductor device is provided. A semiconductor device includes a semiconductor substrate (not shown), an interlayer insulating film 102 formed on the semiconductor substrate and a multiple-layered insulating film 140 provided on the interlayer insulating film 102. The semiconductor device also includes an electric conductor that extends through the multiple-layered insulating film 140 and includes a Cu film 120 and a barrier metal film 118. The barrier metal film 118 is covers side surfaces and a bottom surface of the Cu film 120. An insulating film 116 is disposed between the multiple-layered insulating film 140 and the electric conductor (i.e., Cu film 120 and barrier metal film 118).