Time scale matching of dynamically operated devices using composite thermal capacitors

A new thermal management solution is proposed to maximize the performance of electronics devices with dynamically managed power profiles. To mitigate the non-uniformities in chip temperature profiles resulting from the dynamic power maps, solid–liquid phase change materials (PCMs) with an embedded heat spreader network are strategically positioned near localized hotspots, resulting in a large increase in the local thermal capacitance in these problematic areas. The resulting device, called composite thermal capacitor (CTC), can theoretically produce an up-to-twenty-fold increase in the time that a thermally constrained high heat flux device can operate before a power gating or core migration event is required. A prototype CTC that monolithically integrates micro heaters, PCMs and a spreader matrix into a Si test chip was fabricated and experimentally tested to validate the efficacy of the concept and to gain an insight into phase change heat transfer in a spatially-confined environment on the microscale. As the most significant result, an increase in allowable device operating times by over 7× has been experimentally demonstrated, while operating a device at heat fluxes approaching 400 W/cm2.