Moisture-stable aluminum nitride via conformal Parylene passivation for reliable high-performance thermal interface materials

초록

Aluminum nitride (AlN) is a promising thermal interface material (TIM) filler owing to its high thermal conductivity (similar to 300 W m(-1) K-1), electrical insulation, and dielectric properties; however, its intrinsic vulnerability to moisture-induced hydrolysis leads to phase transformation into Al(OH)(3), causing a severe loss of thermal conductivity and long-term reliability. In this study, we employ a conformal Parylene chemical vapor deposition coating as an effective passivation approach to enhance AlN's moisture resistance while preserving its intrinsic thermal and electrical characteristics. A uniform, defect-free Parylene layer effectively blocked moisture ingress and suppressed hydrolysis-induced degradation. Epoxy composites incorporating Parylene-passivated AlN retained 97 % of their initial thermal conductivity even after 10 days of immersion in 100 degrees C water under extreme hydrothermal conditions, whereas pristine AlN retained only 23 %. Infrared thermography and LED heat dissipation tests confirmed stable and superior heat transfer performance under prolonged moisture exposure. Furthermore, the composites maintained high volume resistivity (>6.9 x 10(13) Omega cm) and structural integrity after 100 thermal shock cycles between -20 degrees C and 100 degrees C. By applying AlN, a next-generation thermal management material attracting considerable attention, this Parylene-based passivation demonstrates strong potential for realizing reliable, high-performance TIM composites for practical high-power electronic applications.

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