Aluminum Oxynitride Films for Use in Power Electronics and Advanced Packaging

Power semiconductors and other electronic applications typically require electrical isolation on the one hand and highly efficient cooling of the devices on the other hand. Balancing electrical isolation, coefficient of thermal expansion, thermal resistance, and thermal reliability performance characteristics are challenging. All solutions on the market today compromise on one or more of these areas. Presently metallic plates bonded to rigid ceramics, so-called AMB (active metal brazing) and DCB (direct copper bonding) substrates are used for those applications. AMBs and DBCs are limited however in terms of thermal conductivity due to the thickness of the rigid ceramic, typically in the 250µm range. They are further limited by the innate mechanical robustness of their base ceramic. AlON thin film technology possesses an optimum combination of these characteristics in addition to offering mechanical robustness while being able to withstand significant mechanical forces. In addition, our proprietary deposition system ensures atomic bonding with the substrate, with near 100% density, free of defects and is applied at low temperature (< 300 ’C) and at very thin layers (100 nm - 50 um+) with typical use cases requiring only 10-15 um for above 5000 volt standoff. Results of electrical isolation, thermal conductivity, film stress and film adhesion of AlON will be reported, and dependencies on the film thickness, and the substrate surface quality will be discussed.