Development of Flip Chip on Flex Structure for Packaging Integrated Power Electronics Modules

Integrated power electronics modules (IPEMs) are envisioned as integrated power modules consisting of power semiconductor devices, power integrated circuits, sensors, and protection circuits for a wide range of power electronics applications, such as inverters for motor drives and converters for power processing equipment. Integration in power electronics is a rather complex process due to incompatibility of materials and processing methods used in fabrication, and due to the high energy levels these components must handle. Innovative 3-D integration technologies rather than planar integration approach are desired to be developed in order to meet the system requirements. Packaging involves the solution of electrical, mechanical and thermal problems. As a result, packaging of IPEM requires a multidisciplinary effort, encompassing the areas of materials, power semiconductor devices, fabrication processes, circuits and control, magnetics, thermal design and analysis, packaging, computer aided design integration, manufacturing as well as application considerations. This chapter is focused on designing and fabricating a reliable and high performance packaged IPEMs eliminating the usage of wire bond in the process. We have developed a threedimensional approach, termed flip chip on flex (FCOF), for packaging high-performance IPEMs. The new concept is based on the use of solder joint (DBGA chip scale package), not fine aluminum bonding wires, to interconnect power devices. This packaging approach has the potential to produce modules having superior electrical and thermal performance and improved reliability. We have demonstrated the feasibility of this approach by constructing half-bridge converters (consisting of two IGBTs, two power diodes, and a simple gate driver circuitry) which have been successfully tested at power levels over 30 kW.