High Performance Film-Type Thermal Interface Material Containing Vertically Aligned Carbon Nanofibers

This study examined a high-performance filmtype thermal interface material (F-TIM) with vertically aligned carbon nanofibers (VACNFs). Unlike conventional TIMs, which are composed of stacked, randomly oriented fillers of varying size, silicone-based F-TIMs with VACNFs provide high z-axis thermal conductivity and are highly compressible, with the ability to conform to surfaces of varying roughness. Thus, the heat transfer performance and bond line thickness (BLT) of the package can be controlled accordingly. In the present study, the maximum thermal conductivity of the F-TIM was 40 W/mK. The test vehicle was a 50 mm x 50 mm package that bonded with a 16 mm x 15 mm thermal testing die with a 150-W power input. Experiments revealed that the overall thermal resistance of a 100 mu m-thick F-TIM was less than 0.036 degrees C/W. In contrast to the thermal resistance of a typical TIM, that of the VACNFs could be reduced by approximately 60%. Thermal cycling and high-temperature stability tests did not degrade the VACNFs, indicating that the F-TIM had excellent thermal stability.