Assessment of a heat spreading solution for hot spots cooling in compact packages

Heat generation in integrated circuits has become in few decades one of the most limiting factors for performance improvement in mobile device components, such as cell phones or tablets. In these devices, heat dissipation is limited to a few Watts as state of art cooling systems, such as heat-sinks or fans, do not fit with the dimensional and power consumption constraints. Amongst the solutions proposed for circuit cooling, the implementation of heat spreaders is probably the most suitable alternative for compact packages due to their ease of manufacturing and low cost. The objective of this work is therefore to study the performance of a high thermal conductivity layer directly integrated at the die level in the scope of short term industrial implementation. In particular, we compare both the hotspot temperature reduction and the temperature profile of the die using either copper or a graphite based material. Temperature reductions over 80°C have been measured for the best case scenario, with a thermal resistance enhancement of 61% at the die stack level. Finite volume simulations are finally presented in order to explain the thermal flux of the system.