Structural models and design rules for on-chip micro-channels with sacrificial cores

Abstract

This paper provides a structural analysis of hollow silicon dioxide micro-channels that have applications in microfluidics and photonics. A specific fabrication method is highlighted that uses aluminum as a sacrificial material. Possible causes of failures that occur during fabrication are investigated, and internal pressure produced during the fabrication process is identified as the most likely failure mechanism. Three models are developed for the fabricated micro-channels. Models based on elementary beam theory and energy methods verify a nonlinear finite element model. Design parameters in the finite element model are varied to investigate which have the greatest effect on structural strength and ultimate failure. Experimental results are used with the model to estimate the pressure at failure. Finally, based on the model and experimental results, a rule is developed for the design of the hollow micro-channels described in the paper: maintain the width-to-thickness ratio below 35.