Methods for Evaluating Advanced Electronics Cooling Systems
As predicted by Moore’s law, microprocessor power dissipation is on a steady rise. In addition, the current technology is also enabling considerable feature size reduction resulting in an even sharper increase of local heat fluxes on dies. If the current pace continues, estimates indicate that power densities of 100 W/cm will eventually be reached. In fact, hardware manufacturers have determined that dual core processor technology is the path to profitability. A processor with two 2.5-gigahertz processors can outperform a chip with a single 3.5-gigahertz processor in certain situations. The higher the temperature of a typical semiconductor, the lower its performance reliability and life expectancy. The inverse proportionality is not linear, but exponential, meaning that a mere reduction in chip temperature will have a considerable effect on both performance and durability. Since the final sink temperature, ambient air temperature, is constant, removing the ever increasing heat fluxes while maintaining the same junction-to-ambient temperature will only be possible through the introduction of advanced cooling systems. Examples include active heat sinks, air jet impingement, micro channel cooling, heat pipes, immersion cooling, and spray cooling. Those systems, though far superior in heat removal rates, pose a more challenging problem to the designer and require novel tools for their design and analysis.