A semiconductor device including two silicon wafers stacked and bonded together with bumps of one wafer electrically coupled with those of the other wafer, in which generation of voids on the junction surface between the silicon wafers is suppressed. Due to a recess made in the surface of a buried conductive film, a cavity is formed in the junction surface between the silicon wafers. The ends of the cavity extend to the periphery of the junction surface between the silicon wafers. This allows the air trapped on the junction surface between the silicon wafers to get out through the cavity, thereby reducing the possibility of generation of voids on the junction surface.