HIGH TEMPERATURE PACKAGING

Silicon Carbide (SiC) and Gallium Nitride (GaN) have the potential to operate as a controllable switch at temperatures theoretically up to at least 600 °C. This capability presents a unique opportunity to surpass the fundamental limitations of current electronic technology, where operation is restricted to maximum temperature thresholds ranging between 125 and 150 °C. In effect, the introduction of wide bandgap based technology in an electronic system allows for the temperature to be treated as a design variable instead of a major limiting factor. This is a significant advantage over a wide range of applications which demand higher power densities, higher performance, and operation in extreme environments.

While fulfilling the promise of reliable and commercially viable high-temperature electronic systems requires a number of advancements in SiC and GaN device technology itself (higher yields, higher current ratings, active structure reliability, etc.), it is only part of the solution. One of the more challenging issues is encountered in the absence of adequate high-temperature packaging materials, processes, and techniques.

Electronic packaging serves as the functional link between the bare, sensitive electronic devices and the rest of the system. It incorporates a variety of elements ranging from interconnection at the device level (die attach, wire bonds, passivation, substrates, etc.), protection and integration at the module level (voltage isolation, sidewalls or module housing, three-dimensional multi-level designs, etc.), and system implementation (bussing, volume and weight requirements, etc.).

APEI, Inc. is striving to develop and advance packaging technology in order to push the limits of what is possible with power electronics. APEI researchers are working on advanced techniques, processes, and materials to enable reliable operation at elevated temperatures to achieve high power densities and to operate reliably in extremely severe environments. Areas currently in development include:

• High thermal conductivity low stress die attaches
• Advanced wire bond materials and processes
• Wire bondless interconnects
• Resilient module housings with embedded metal tracks
• Integrated power and control substrates
• High g-force (>14,000 g) high-temperature (>450 °C) packaging
• Voltage blocking and surface protecting passivation

APEI, Inc. is aggressively pursuing relevant and cost effective techniques across the entire temperature spectrum achievable with SiC and GaN. The focus is to develop a range of packaging approaches which can be matched to specific application requirements and expectations.