US Patent 9161453 Wiring board and method of manufacturing the same

A wiring board includes a core layer; a through hole penetrating through the core layer in a thickness direction of the core layer; and an electronic part accommodated inside the through hole, wherein the through hole includes a first opening portion provided on a first surface of the core layer, a second opening portion provided on a second surface of the core layer, and an inward protruding portion inwardly protruding relative to the first and second opening portions, and wherein the electronic part is held by the inward protruding portion.