Experimental investigation of thermal performance of microchannel heat sinks with pin-fin structures fabricated via lithography method

Abstract Microchannel heat sinks (MCHSs) are compact cooling devices that play a crucial role in modern thermal management systems. They offer efficient heat transfer and are widely used in electronic cooling. One of the major challenges in the practical implementation of MCHSs is maintaining consistent thermal performance under the temperature fluctuations experienced by microchips. Although numerical studies have demonstrated that incorporating pin-fin structures within microchannels can significantly improve heat transfer by disrupting thermal boundary layers and increasing surface area, experimental validation remains limited. This limitation is due to fabrication challenges, particularly in achieving precise and intricate geometries using conventional microfabrication methods. In this study, a rectangular MCHS with embedded pin-fins was fabricated using the lithography technique, with polydimethylsiloxane as the channel material. The fabrication process considered different exposure powers of 5 mW and 10 mW. The accuracy of the fabricated microchannel was analysed using scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX). The heat transfer performance was then evaluated under different input temperatures: 30, 40, 45, 50, 55, and 60 °C while maintaining a constant flow rate of 500 µL/min. The results show that the heat transfer rate increases with higher input temperatures, which can be attributed to the greater temperature differentials that drive more intense heat flux through the channels. These findings highlight how temperature fluctuations in microchips affect the heat transfer rate and, consequently, the overall MCHS performance. The study also emphasises the need for improved fabrication methods to support further experimental validation and implementation of complex pin-fin designs.