Patent ID: 10818518

Abstract:
A plurality of surface mounting components are arranged on a component mounting surface of a transfer substrate. A resin layer is formed on the transfer substrate and the plurality of surface mounting components are buried in the resin layer. The resin layer is peeled off the transfer substrate, with the plurality of surface mounting components buried in the resin layer, to expose a surface resin layer. An intermediate auxiliary layer is provided on the exposed surface of the resin layer. The intermediate auxiliary layer has openings to expose respective mounting terminals of the surface mounting component. Metal materials are arranged in the openings. A wiring sheet which includes a thermoplastic resin sheet with an electrode pattern and a plurality of unmetallized via patterns is joined to the intermediate auxiliary layer so that each of the via patterns aligns with a respective one of the openings in the intermediate auxiliary layer. Heat treatment is performed to fuse the thermoplastic resin sheet to the intermediate auxiliary layer and to metallize the via patterns to connect the via patterns to the openings in the intermediate auxiliary layer and therefore the mounting terminals and the electrode pattern through the metal materials and the via patterns.