A semiconductor device 20 formed on a semiconductor chip substrate 30 has a plurality of circuit blocks made up of circuits each containing at least a metal oxide semiconductor (MOS) transistor 36, the circuit blocks being covered on top with a protective film 41 to protect the circuits. A plurality of bumps 23a, 23b, 23c are formed, at least via the protective film 41, only on circuit blocks whose current-carrying ability and threshold voltage do not satisfy predetermined values and which are in need of performance enhancement. The bumps 23a, 23b, 23c impose stresses on the MOS transistors 36, increasing the mobility of the MOS transistors 36 and thereby improving the performance of the semiconductor device 20.