Transfer layer technology for the packaging of high power modules

Most power electronic modules are specifically designed for the customer and this entails intense labour during the production phase. The monolithic integration for power electronic devices in the form of power IC has not proven to be efficient, neither from a technical, nor from an economic point of view. In a typical high power module the power devices are assembled on a heatsink and, driver, sensor and protection circuits are mounted on separate PCBs assembled to the power devices. This results in low performance and high cost. Higher integrated power modules are produced assembling power devices in die format onto a DCB (Direct Copper Bonding) substrate and interconnect them by wire bonding technique. The relative driver, sensor and protection circuits are surface mounted on a separate PCB assembled with the former. Unfortunately, there are certain fundamental limitations to the above described packaging mainly due to wire bonding. In spite the fact that this technology has made enormous progress in recent years, it still limits the possibility of three dimensional packaging and puts major limits on creating low EMI and high frequency circuits. In this paper we present an already tested technology for compliant interconnection of power devices that overcomes the limitations of wire-bonding. In the development of this new technology, compatibility with wire-bonding has been strongly enforced to provide a solution that could be retrofitted to existing modules.