Mold die and method for manufacturing semiconductor device using the same

An object of the present invention is to provide a technology that can seal the opening of the interposer by transfer mold with the leak of the insulating resin from the above-described opening prevented. A mold die comprising a first die having a recess in a predetermined form and a second flat die, the above-described mold die being for disposing the above-described first die on a surface of a wiring board which has a plurality of openings and bears a semiconductor chip via an elastic material, which surface bears the above-described semiconductor chip, and for disposing the above-described second die on a back of the above-described surface of the above-described wiring board which bears the above-described semiconductor chip, and for sealing with an insulating resin a periphery of the above-described semiconductor chip and at least one of the above-described openings of the above-described wiring board, wherein the above-described second die comprises a protrusion around an area overlapping the above-described opening sealed with the above-described insulating resin.