Thermal cycling analysis of microgyroscope chip embedded with through-silicon vias by finite element method

The through-silicon vias (TSVs) technology is developed recently on the microelectromechanical system (MEMS) device chip for transmitting signal and reducing the energy loss of electronic package. The reliability of this chip depends on the bonding between TSVs and solder balls. In this paper the effect of the different bonding ways between TSVs and solder balls on the thermal cycling behavior of microgyroscope chip is investigated by finite element method. In the analysis, different contacting conditions between TSVs and solder balls were evaluated, including two cases with pads added between solder balls and TSVs. The analysis included the microgyroscope chip with underfill around the solder balls. The results show that the microgyroscope chip without underfill couldn´t sustain one thermal cycle; the fatigue life increased substantially for the chip with underfill. The fatigue life of microgyroscope chip increased about 27% for the case the solder ball having the same top contacting diameter as TSV and increased 21% if the pads, made of the same material as TSVs, were added between TSVs and solder ball. The results indicated that the finite element results agreed with that of the thermal cycling test. This paper showed the different ways of the packaging structure design to improve the reliability of microgyroscope chips in the packaging process.