Use of Carbon Nanofibers to Improve Thermal Pathways and Reduce Weight in Radar Transmitters

The high thermal stress created by advanced electronic systems limits their performance potential. More efficient methods of heat removal are required to cope with this problem. Recent developments in carbon nano technology offer promise of providing possible solutions. A primary bottleneck in the thermal pathway is the attachment layer between components. The attachment layer between the electronic components is the weak link in the thermal chain. The current technology utilizes adherent organic polymers filled with thermally conductive particulates such as carbon or aluminum. Unfortunately organic polymers have inherently poor thermal conductivity and are impossible to apply without gas bubble entrapment, which further increases the heat resistance of the attachment layer. The best performing attachment materials currently available have heat conductivities under 10 W/m-K. A three fold improvement would dramatically enhance overall heat removal and hence chip performance. Substitution of carbon nano tubes for the filler is not likely to greatly improve performance. The use of carbon nanofiber to construct a micro in situ heat pipe as a means of achieving direct heat conduction away from the semiconductor packages and between other heat management devices is proposed. Success with this approach will produce opportunities to enhance performance and reduce weight. BENEFIT: Sophistication of electronic products used by both military and commercial markets continues to increase. However, maintaining the current rapid rate of performance improvement and associated size/weight reduction faces several significant engineering challenges. One major issue with continued advancement of electronics performance is heat removal from the individual electronic chips on a circuit board. KaZaK proposes the development and demonstration of a novel method for introducing a revolutionary increase in the conductivity in the interface between the bottom of an electronic chip and its underlying heat spreader. The thermal barrier associated with current attachments is one of the major impediments restricting removal of heat from increasingly densely packed electronics. If the proposed micro heat pipe approach suggested by KaZaK proves successful, our system should be rapidly and widely accepted by manufacturers of high performance electronics systems. We would expect that the first implementations will be by military primes, but once some period of positive test results in developed, applications should expand quickly to all electronics manufacturers.