ADVANCED THERMAL TECHNOLOGIES
The program is focused on the development of ultrahigh thermal conductivity carbon fiber for use in graphite-metal composites. The target end use applications for the graphite-metal composite material are high power electronic packaging. There is a critical need to control the operating temperature of an electronic device as well as minimize differential thermal stresses resulting from thermal expansion between a semiconductor die and its packaging substrate. The use of graphite fiber in a metal matrix produces a composite with high thermal conductivity and controlled CTE, the two key requirements for a material to be used in electronic packaging components. High thermal conductivity carbon fibers can only be produced from a mesophase pitch precursor fiber. Currently there are a limited number of commercially available mesophase pitch derived carbon fibers. None of the available commercial fibers are able to produce a graphite-metal composite with the optimal thermal properties that are required to support next generation power electronics. The proposed carbon fiber development effort is focused on producing a unique mesophase pitch derived carbon fiber that would enable a 150% increase in the thermal conductivity of a graphite-metal composite while maintaining the CTE of the graphite-metal composite within the ideal range of 5 to 9 ppm/oC required for semiconductor die attachment. The technology developed in this Phase I research program will enable the manufacture of cost effective graphite-metal based packaging products that offers improved thermal properties critical to thermal management solutions for high power electronics. The market for graphite-metal composite packaging products that would be enabled by the mesophase pitch derived carbon fiber technology include: (1) RF power amplifiers for communication and radar systems; (2) insulated gate bipolar transistor switching devices for power conversion systems; (3) light emitting diode devices for solid state lighting and (4) high power commercial and medical laser devices.