Development and Characterization of Thermal Enhancement Structures for Single-Phase Liquid Cooling in Microelectronics Systems

In this paper, the development and characterization of thermal enhancement structures for single-phase liquid cooling in microelectronics systems are presented. Miniature heat sinks with three different types of thermal enhancement structures were examined. The first type was a metallic microchannel heat sink (MMCHS) made of aluminum with the channel dimensions of 15 mm (length) × 0.2 mm (width) × 2 mm (height). The second type was the silicon microchannel heat sinks (SMCHS) made through the deep reactive ion etching technique on a 6 inch wafer, with identical channel height of 0.45 mm and average channel widths of 66.6 μ m and 46.6 μ m, respectively. The last type was the metallic foam heat sinks (MFHSs), which were formed by brazing porous foam materials of high pore density onto copper base plates. All three types of heat sinks were fabricated and experimentally characterized by incorporating into electronic packages in standard flip chip ball grid array format. Characterization results indicate that, given a thermal window of 50°C, both the MMCHS and MFHSs can achieve an equivalent package heat dissipation above 100 W/cm² at moderate pressure drops and the SMCHS above 200 W/cm² at larger pressure drops. A comparison of thermal enhancement and manufacturability of the three types of heat sinks is also presented.