A semiconductor package includes a first semiconductor chip and a second semiconductor chip stacked on the first semiconductor chip. The first semiconductor chip includes a substrate having a first via hole, an insulation interlayer formed on the substrate and having a first bonding pad in an outer surface thereof and a second via hole connected to the first via hole and exposing the first bonding pad, and a plug structure formed within the first and second via holes to be connected to the first bonding pad. The second semiconductor chip includes a second bonding pad bonded to the plug structure which is exposed from a surface of the substrate of the first semiconductor chip.