Impingement heat sink optimization for microprocessors with significant hot spots

As processing capabilities of microelectronic devices increase, so does the power dissipated by them. To add to that, power distributions are non-uniform and this may create significant hot spots. These devices require improvements in thermal performance of the entire system due to their higher power dissipation and non-uniform power distribution. This study looks at impingement type heat sinks, which are commonly used for desktop microprocessors and other applications with the objective of improving thermal performance. One key feature of the heat sinks studied here is their smaller size compared to the ones that are commonly used for desktop applications. This would save space on the board and the system. Detailed parametric studies are conducted covering a broad range of different air flow rates, shapes and fin heights. The studies are based on a numerical analysis using a commercially available finite volume approach. Conclusions are drawn from the results outlining some general design guidelines. The objective of the different designs is to reduce chip temperature and the pressure gradient across the heat sink. The pressure gradient at the center of the heat sink, near the base tends to be especially high which reduces the airflow and hence the transport in that region. This study examines different fin shapes for parallel plate fins with material removed from the central region of the heat sink resulting in improved thermal performance, lower operating temperature and pressure gradients.