Solid and Vapor Chamber Integrated Heat Spreaders: Which to Choose and Why

The performance and reliability of semiconductor electronics require that thermal management hardware be used to adequately cool devices, components, and packages. A vital component of many devices, including but not limited to PAs, CPUs, GPUs, and LEDs, is the integrated heat spreader (IHS). IHSs are implemented to spread the heat from the small electronic component to a larger area in order to facilitate sufficiently low thermal resistance active or passive cooling to the final fluid-cooled heat sink in the stack. One question that still needs to be addressed for electronics packaging is “Under what circumstances do vapor chamber heat spreaders outperform solid IHSs?” This paper is aimed at providing a straightforward approach to addressing this question, specifically during the early “scoping” design stage. Sufficiently accurate steady-state thermal network models for both solid and vapor chamber IHSs are proposed for estimating the overall stack resistance of a package, including TIM1, IHS, TIM2, and convective heat sink. In this way, the performance of both heat spreading technologies can be compared and contrasted over a range of geometric and operating parameters without having to resort to complex numerical models, which may require specialized expertise and/or be too expensive and time-consuming for early-stage design phases of electronic packages.