An object relates to an electrode of a semiconductor device or a method for manufacturing a semiconductor device, which includes a bonding step, and problems are: (1) high resistance of a semiconductor device due to the use of an Al electrode, (2) formation of an alloy by Al and Si, (3) high resistance of a film formed by a sputtering method, and (4) defective bonding in a bonding step which is caused if a bonding surface has a large unevenness. A semiconductor device includes a metal substrate or a substrate provided with a metal film, a copper (Cu) plating film over and bonded to the metal substrate or the metal film by employing a thermocompression bonding method, a barrier film over the Cu plating film, a single crystal silicon film over the barrier film, and an electrode layer over the single crystal silicon film.