Power cycling reliability of time-reduced sintering for attaching SiC diodes using nanosilver film

Inhalt:
We present a comparison of the power cycling performance of three SiC die attachments, namely sintered Ag with sintering times of 5 s and 5 min, and Pb5Sn solder joints, over a temperature range of 50 to 200 ºC. The evolution of the effective thermal conductivities and structural changes of the die attachments were characterized at regular power cycles intervals. Results indicate that the effective thermal conductivities correlated well with the observed evolution of microstructure. The power cycling reliability of the 5 s sintered Ag joint is comparable with that of the 5 min sintered Ag joint, and 15 times more reliable than the Pb5Sn solder joint, assuming an effective thermal conductivity of 30 W/(m·K) is taken as criterion of failure. This study has demonstrated that high-reliability sintered joints can be achieved using a die bonder with a cycle time of several seconds, opening a route to rapid assembly of high performance power electronic modules using industry-standard processes.