Active power cycling results using copper tin TLPB joints as new die-attach technology

A new highly reliable die-attach technology for high operating temperature is called Transient Liquid Phase Bonding (TLPB). The TLPB is based on phase transformation into intermetallic phases using a low melting solder layer and a high melting bonding surface. Due to this fact the re-melting temperature of such a transformed joint increased up to the decomposition temperature of the intermetallic phase, which might be more the 200 K of the used soldering temperature. In active power cycling analysis between +30 degC and 180 degC (DeltaT = 150 K) the TLPB showed more than 100-times longer lifetime compared to eutectic SnAg-solder. Furthermore, other failure mechanisms were found compared to Sn-based solder joints such as fatigue cracks in the copper layers of the DCB-substrate and the chip interface as well as delamination between the AI203-layer and the bottom Cu-layer of the DCB.