High Thermal Conductivity, CTE Matched Heat Spreader with MicroChannel Structures

Thermal management of radar systems requires the removal of large amounts of waste heat, and in order to maximize the rate of waste heat removal it is critical that the thermal resistance of the heat path be minimized. RTI has successfully developed a nanocomposite material that has a significantly increased thermal conductivity over that of copper and a coefficient of thermal expansion that can be matched to that of semiconductor materials. This material would be ideal for the purposes of reducing thermal resistance and mechanical stresses in the material stack-up of modern and future radar systems. The effort proposed here is to further develop this material and its fabrication process such that nanocomposite structures could be made with internal volumes. These internal volumes could be used to allow for convective heat transfer very near the semiconductor die surface. Bringing the convective heat transfer so close to the T/R module and using a highly thermally conductive material to do so would dramatically reduce the thermal resistance and simultaneously reduce the mechanical stresses at the interface. Therefore, a significant leap in the thermal management of radar systems can be realized.