| Summary: | Microchannel heat sinks have been recognized as efficient cooling platforms for thermal management of miniaturized devices because of their compact structure. Unlike most microfabrication processes, laser micromachining is a versatile direct writing method to rapidly produce microchannels in brittle substrates such as silicon wafers. In this study, an all-laser fabrication method is proposed to fabricate a microfluidic heat sink for silicon devices. Lasers are used for engraving microchannels on a silicon wafer, drilling inlet/outlet holes in quartz glass cover, and welding the Si sample and quartz glass cover. The entire fabrication process is completed within two hours. The microchannel surface is converted into a hydrophilic wall as proven by contact angle measurement, and a water flow is easily introduced to the channel as a cooling fluid. The boiling heat transfer performance of the fabricated microfluidic channel is evaluated by applying heat to the bottom of the device. A micro-heater placed underneath the Si substrate is also prepared using a laser to induce selective sintering of a conductive Ag layer. The heat generated by the heater is successfully removed by boiling heat transfer, and the critical heat flux is measured to be ∼ 55.2 W/cm2 at a water flux of 208 kg/m2s.
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