Power Electronics Packaging Reliability
Power electronics packaging around a semiconductor switching device determines the electrical, thermal, and mechanical properties of a power electronics component. NREL researchers are characterizing the reliability of emerging packaging technologies that could potentially operate more efficiently and reliably under higher temperatures than current methods. These high-temperature-capable technologies, such as bonded interface materials, are a key enabling technology for compact, lightweight, low-cost, and reliable power electronics components in electric-drive vehicles.
Existing power electronics packages use silicon devices and lead-free solder alloys in their construction. Manufacturers of new power electronics components are transitioning to using devices with wide-bandgap materials in these components for improved performance, reliability, and cost. High-temperature bonded interface materials are an important facilitating technology for compact, lightweight, low-cost, reliable power electronics packaging that fully utilizes the capabilities of wide-bandgap devices. NREL research on high-temperature bonded interface materials can be roughly classified into three categories: silver sintering, high-temperature soldering, and transient liquid-phase sintering.
Sintered-silver materials operated continuously look promising for reducing the degradation of power electronics packages at temperatures of 200C or higher. NREL is characterizing the reliability of sintered-silver materials and processes from a variety of manufacturers to develop a baseline of sintered-silver bond reliability. In addition, NREL is developing tools that can predict the reliability and life of sintered silver, enabling a time- and cost-effective design process. The performance and reliability of emerging techniques, such as atomic-level bonding, are also under investigation as a longer-term development goal.