A semiconductor package structure includes a base. A first die is mounted on the base. The first die comprises a plurality of first pads with a first pad area arranged in a first tier. A plurality of second pads with a second pad area is arranged in a second tier. A second die is mounted on the base. The second die includes a plurality of third pads arranged in a third tier. A first bonding wire has two terminals respectively coupled to one of the first pads and one of the third pads. A second bonding wire has two terminals respectively coupled to one of the third pads and one of the second pads.