Study on the Effect of Cu Buffer and Cu-wire Bonds on SiC Device Performance

In the realm of power devices, the conventional direct Al-wire bonding technology has been extensively used for packaging Si-based chips. With the advent of SiC chips and the application of sintered silver materials, there is a need for innovative packaging technologies to meet the more demanding requirements. This paper aims to discuss the effect of adding Cu buffer sintered on the top surface of the chip and Cu wire bonding on the thermal, electrical and power cycle reliability of SiC device. The investigation involved a combination of simulation and experimental validation. The results showed that the addition of Cu buffer and Cu wire bonding increased the lifetime by 2.3 times and 7.8 times, respectively, compared to direct aluminum wire bonding. This research also provides a packaging solution for achieving higher reliability in Al-wire bonded SiC devices. Finally, we use digital image correlation (DIC) and cross-sectional microscopy to analyze differences in power cycle reliability and failure modes.