All laser-based fabrication of microchannel heat sink. (September 2022)

• Record Type: Journal Article
• Authors: Zhou, Haoyu; Lee, Jungbae; Kang, Minsoo; Kim, Hakgae; Lee, Hyoungsoon; In, Jung Bin
• Is Part Of: Materials & design. Volume 221(2022)
• Publication Date: 2022-09
• Subjects: Microchannel heat sink -- Laser processing -- Flow boiling heat transfer -- Laser machining; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.110968
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Rapid all laser-based fabrication of silicon microchannel device. Laser engraving of microchannels, laser drilling of inlet/outlet holes, laser sintering of film heater, and laser welding for packaging. Application in microchannel heat sink for miniaturized devices. Abstract: 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/cm 2 at a water flux of 208 kg/m 2 s.