A semiconductor device comprises a first semiconductor die and a second semiconductor die. The first semiconductor die comprises a at least one first bond pads formed on a peripheral region of the first semiconductor die, a at least one re-distributed layer (RDL) pads formed on a center region of the first semiconductor die, and a at least one wire routes interconnecting the first bond pads and the RDL pads. The second semiconductor die is disposed over the first semiconductor die, wherein the second semiconductor die has a at least one second bond pads electrically connecting to the RDL pads via bonding wires; wherein the RDL pad is supported by at least a buffer layer.