According to an aspect of the invention, a semiconductor device includes a substrate having an opening area, a first semiconductor chip, and a second semiconductor chip. The first semiconductor chip has a first electrode for high-speed communication and that is disposed around the opening area on the substrate. The second semiconductor chip has a second electrode and third electrode for power and low-speed communication and that is disposed on the first semiconductor chip so that the first electrode is coupled with the second electrode by electrostatic coupling and dielectric coupling, the third electrode facing the opening area.