A semiconductor device manufacturing method includes (a) bonding a first surface of a metal plate to a substrate, (b) forming a plurality of metal posts that are arranged in vertical and lateral directions in a plan view and include a first metal post and a second metal post, by partially etching the metal plate bonded to the substrate from a second surface of the metal plate, (c) fixing an integrated circuit (IC) element to the second surface of the first metal post, (d) coupling the second metal post and a pad terminal of the integrated circuit element via a conductive material, (e) resin-sealing the integrated circuit element, the metal posts, and the conductive material by providing a resin onto the substrate, and (f) removing the substrate from the resin and the first surfaces of the metal posts sealed using the resin.