US Patent 8137497 Method of manufacturing wiring substrate

A method includes the steps of providing a first tape base material on a single side of a stiffener substrate, forming, on the stiffener substrate, a cavity for accommodating a semiconductor chip therein, inserting the stiffener substrate in the cavity and providing the stiffener substrate on the first tape base material, sealing the semiconductor chip and the stiffener substrate with a sealing resin, and removing the first tape base material and forming a build-up layer on a tape removing surface.