AlN coatings with high thermal conductivity and excellent electrical properties for thermal management devices

Thermal conductive materials with low dielectric constant under high frequencies play an important role in high-power integrated circuits packaging. The application of Cu in the packaging substrates is limited due to the high dielectric constant. In this paper, the AlN coatings were deposited on the Cu substrates to maintain the high thermal conductivity and obtain excellent electrical properties for the first time. The microstructure, thermal conductivity and electrical properties of the AlN/Cu systems were adjusted by duty cycles. The results show that improving the duty cycle reduced the hcp-AlN (002) preferred orientation degree of the coatings. The growth structure of the coatings could be regulated by increasing the duty cycle, which induced the grain and particle size first increasing and then decreasing. AlN/Cu systems improved the thermal conductivity of Cu. All coatings show far higher resistivity than Cu and 0.006–0.24 low dielectric loss. The minimum dielectric constant (5.6) of the coating at 2000 kHz frequency was obtained. The AlN/Cu systems in this paper realize high thermal conductivity and excellently dielectric properties, meeting the application in high-power integrated circuit packaging.