Steady state thermal conductivity measurements of AlN and SiC substrate materials

Measurements of thermal conductivity on conventional and recently developed electronic ceramics (Al₂O₃, AlN, BeO, and SiC) are presented as part of an effort to incorporate the new high-thermal-conductivity ceramics into microcircuit manufacturing. Motivated by large variations in values claimed by different vendors for ostensibly similar materials, a longitudinal bar apparatus was built to measure thermal conductivities of actual substrate materials on both an individual and a lot sampling basis. The longitudinal bar method is compared to other experimental techniques for measuring thermal conductivity. Room-temperature and high-temperature thermal conductivity results and results on the effects of thick-film processing are presented and discussed. The results indicate that AlN could find substantial use in circuit manufacture