Integrated Circuit Cooling Using Heterogeneous Micropin-Fin Arrays for Nonuniform Power Maps

As microelectronic system density continues to increase, cooling with conventional technologies continues to become more challenging and is often a limiter of performance and efficiency. The challenge arises due to both large heat fluxes generated across entire chips and packages, and localized hotspots with even higher heat flux. In this paper, nonuniform micropin-fin heat sinks are investigated for the cooling of integrated circuits with nonuniform power maps. Four heterogeneous micropin-fin samples were fabricated and tested in single-phase experiments with deionized water to investigate the effectiveness of local micropin-fin clustering for the cooling of hotspots. Cylindrical and hydrofoil micropin-fins were tested, as well as two types of heterogeneous arrays: those with pin-fins clustered directly over the hotspot and those with the high density cluster spanning the entire width of the channel to prevent flow bypass around the cluster. Samples were tested with a uniform nominal heat flux of 250 W/cm(2) as well as a hotspot heat flux of 500 W/cm(2). Local micropin-fin clustering was found to be an effective method of reducing local thermal resistance with a modest pressure drop penalty.