Flip chip contacts for high current conducting assemblies

Merging intelligence with power is one of the hot topics of the last few years. Not only driven by the automotive industry, but also by industrial electronics and consumer electronics, large markets await solutions to joint low power microcontrollers with high power semiconductor switches or regulators. Until now, standard surface mount technology has dominated, although hybrid assemblies also have their market niches. Miniaturisation by integrating the required semiconductor in the form of bare dice into a single package is still a challenge. Chip on board provides a technically feasible solution, but COB has only limited compatibility to the process used for passive component mounting in this package. Flip chip would provide the ultimate solution here, allowing fully SMD compatible processing. Unfortunately, power devices must pass tens of amperes through the contacts and must also dissipate a high thermal load. A detailed investigation to verify reliability under these conditions must be conducted. This paper evaluates the performance of flip chip contacts under both thermal and electrical load. Thermal simulation and metallurgical investigations show the performance of flip chip technology for power assemblies.