SUMMARY

The development of wide band gap semiconductors for power and RF applications as well as high power Si microelectronics has pushed the need for advanced thermal management techniques to ensure device reliability. While many techniques to remove large heat fluxes from devices have been developed, less attention has been paid in the development of new materials which can be integrated into the packaging architecture. This is especially true in the development of thermal interface materials. Carbon nanotubes have been suggested as a possible thermal interface material which can challenge solders because of their good thermal properties and 1-D structure which can enhance mechanical compliance between surfaces. Recent experiments by several researchers have shown that a dense array of vertically aligned carbon nanotubes grown on Si and Cu substrates can provide thermal resistances less than 20 mm2K/W. However, the direct growth of CNTs on microprocessors or bulk metal heat sinks make the implementation of this technology still a challenge of CNT integration. Moreover, the contact resistance between the CNTs and the parts to which they are attached control the overall thermal resistance of the CNT TIM and must be addressed. In this work, we have developed a novel growth and transfer printing method to create vertically aligned CNTs for thermal interface applications. CNTs are grown using a standard process on oxidized Si substrates and then printed onto substrates like Cu, diamond, and SiC using a unique bonding process. Thermal resistances of the CNTs and the bonded interfaces were measured using the photoacoustic method. The adhesion of the CNTs was measured through tensile tests. Finally, their heat dissipation capabilities were demonstrated through incorporation with LEDs mounted on copper and comparing their junction temperatures with samples bonded using lead free solders.