SBIR-STTR Award

Copper-graphite composite is proposed for a thin liquid-cooled cold plate for high density electronic thermal management. The proposed cold plate will have CTE in the range of 2~9x10-6 /°C to match those of semiconductors such as SiC, silicon, GaAs, as well as ceramic substrates. The composites have a thermal conductivity of ~200 W/m K in the through-plane direction and ~300 W/m K in planar directions. The proposed cold plate will be able to withstand temperatures up to those of copper-silver brazing (780 degree C) for subsequent die attachment or substrate bonding, without re-melting the brazing joint.

Keywords:
Thermal Management, Radar, Liquid Cooling, Heat Sink, T/R Module; Hpa; Wide Band Gap; High Voltage Gaas

Two approaches to high performance base plates for advanced thermal management applications are proposed. Inexpensive high performance Al/Gr composites have been developed with a quasi-isotropic thermal conductivity (TC) of 600 to 750 W/mK and corresponding thermal expansion (CTE) of 7 to 3 ppm/K. CTE matching base plates for advanced multi-channel phased array radar systems enable hard (solder) bonded GaN packages for maximum thermal efficiency. Either liquid cooled or forced air convection cooled base plate can be used for a multi channel array with high thermal dissipation requirements. FEA thermal modeling will be used to design of the ~8 by 12” baseplate. The goal is a two to three-fold increase in power density in wide bandgap semiconductors and to manufacture radar arrays with greater than 100 channels on a single ~page sized baseplate. In a parallel project, baseplates Al/Gr or Cu/Gr composites mounted with high performance single use devices will be cooled by liquid to vapor phase change material at the core of the baseplate. This combined with direct die attach enabled by CTE matching results in high performance systems for limited duration missions. Thermal modeling will determine baseplate design and volume of PCM required.

Keywords:
Thermal Management, Al/Graphite Composites Cu/Graphite Composites Radar, Liquid Cooling, Baseplate Heatsink, Phase Change Material