Electronic boxes need to be quickly and easily attached and removed from the satellite payload deck in a spacecraft structure. Hampering the removal process is the vulcanized (RTV) used as the Thermal Interface Material, TIM. Because of its strong bond, it makes removal of the boxes time-consuming, and difficult to rework. Compounding the problem is the fact that electronics continue to get smaller and higher in power, the interface resistance is becoming the dominant temperature drop in the thermal circuit. The proposed solution is to use Highly Oriented Filament Array (HOFA) technology to improve the through the thickness thermal resistance by extending high thermal conductivity polymer filaments across the interface to contact the opposing side. A layer of HOFA is applied to both the electronics box being cooled and to the payload deck so that the two interface layers mesh like two hair brushes when brought together. The filaments form a high surface area contact conduction path without making an actual bond that is difficult to remove and rework. In Phase 1 several different filament geometries (round, square, rectangular) will be evaluated from various thermally conductive polymer materials. Sample filament materials made from high conductivity polymer formulations will be made using Hot Embossing. These materials will be tested for their effectiveness at meeting the Air Forces defined TIM requirements.
Benefit: Excess heat is the number one cause of failure in modern electronic systems. Concurrently, the electronics industry is facing ever increasing power densities as device sizes shrink and the performance of devices such as processors continues to increase. The associated increasing heat load is a critical issue as chip manufacturers, trying to perpetuate Moores law, find themselves outpacing the capabilities of existing thermal solutions. Power and heat have become the biggest issues for chip manufacturers and companies integrating these chips into everyday devices. Increasingly, the thermal resistance at the interface between the device generating heat and the system used to remove the heat is becoming the weakest link in the thermal circuit. Thus, there is a great need for improved thermal interface materials (TIM) to be satisfied by the proposed work effort.
Keywords: Thermal Interface Material, Tim, Interface Resistance
