Fabrication and testing of silicon-based microchannel heat exchanger inspired by leaf venation pattern for electronic cooling

Abstract

Microchannel heat sinks (MCHS) provide an efficient means to dissipate large heat flux. The task of fabricating MCHS becomes challenging due to availability of large number of newer materials and processes. In this work, tetra methyl ammonium hydroxide (TMAH) etching and LASER machining methods for fabricating the microchannels are compared with respect to dimensional accuracy, the profile of channel, surface roughness, aspect ratio, material compatibility, cost and thermal performance. TMAH etching results in trapezoidal cavity instead of the rectangular cavity, finest surface finish (8 nm), and is suited for batch fabrication. While, LASER machining results in small taper profile (10o to vertical surface), rough surface (2.83 μm), and better dimensional accuracy and is suited for job production. Experimental results show that both MCHS exhibit similar thermal performance at lower flow rates. At higher flow rates, however, LASER fabricated MCHS have 25% higher thermal performance than TMAH etched channels.