A method includes forming grooves in first regions included in a first wafer to form wiring regions defined by the grooves; forming insulating portions in the grooves; joining a surface of the first wafer on which the wiring regions are formed to a first surface of a device wafer including device forming regions after forming the insulating portions; forming through holes in the wiring regions of the first wafer after joining the first wafer to the device wafer, the holes extending through the first wafer; filling the holes with a conductive material; joining a second wafer to a second surface of the device wafer opposite the first surface, the second wafer including second regions; exposing the wiring regions by thinning the first wafer after joining the first wafer to the device wafer; and cutting the device wafer, the first wafer, and the second wafer after thinning the first wafer.