High thermal conductivity ceramic layered system substrates for microelectronic applications

The development of a new material or composite with high thermal conductivity for microelectronics substrate application has attracted huge attention in recent years due to the greater heat generated in today's higher speed processors. In the present work, a highly thermal conductive substrate was fabricated using a layered-system configuration. Carbon fibers, which have a high value of thermal conductivity, were introduced into the traditional alumina substrate material as an interlayer with various layer-thickness ratio. The carbon fiber-incorporated layered system substrates were shown to provide an enhancement of thermal and dielectric properties up to six times of that without carbon fiber. It is, however, noted that the insulating property has also degraded with the introduction of carbon fiber. As a result, it is suggested that there exists an optimum configuration to achieve improvement in both thermal and dielectric properties and keep the material sufficiently insulating. It is also observed that carbon has diffused out from the fiber into the alumina matrix around the carbon fiber. Interfacial analysis was carried out using energy dispensive analysis by X-rays (EDX) and some amorphous phase was found at this region.