Expanding semiconductor chip and semiconductor device

The semiconductor device (1) includes a first semiconductor chip first electrode (21) formed on the surface (2), outwardly from the second semiconductor chip (31) and at least one side surface of the second semiconductor chip a formed resin expanded portion (33), and a dilated semiconductor chip second electrode (35) is formed (3) on the surface. The extended semiconductor chip and the first semiconductor chip, the formation surfaces of the first electrode and the second electrode are opposed, and connects the first electrode and the second electrode to each other. Of the second electrode in the expanded semiconductor chip, a second electrode connected to the first electrode is formed only on the resin extension.