Dynamic thermal management of high heat flux devices using embedded solid-liquid phase change materials and solid state coolers

Dynamic operation and control is an essential tool for thermal management of a number of next generation electronic devices that suffer from localized hotspots with large heat fluxes. Due to limited cooling resources, the time that high heat flux devices can operate before load mitigation approaches must be employed is limited. To mitigate the spatial and temporal non-uniformities in chip temperature that result from dynamic power maps, the authors have introduced a novel thermal management approach that integrates solid-liquid phase change materials (PCMs) with an embedded heat spreader network directly into the die near the hotspots. This combined PCM-heat spreader network, or Composite Thermal Capacitor (CTC), gives the device a large increase in the local thermal capacitance near the hotspots. A prototype CTC that monolithically integrates micro heaters, PCMs and a Si spreader matrix into a test chip has been fabricated and shown to increase allowable device operating times by over 650% and address heat fluxes of up to ~395 W/cm
²
. Coupled to the CTCs are solid state coolers (SSCs) that deliver fast regeneration of the CTCs during throttling events. Experiments that couple thermoelectric coolers to the CTCs, show that system duty cycles of over 50% can be achieved.