Laser-assisted chemical etching for embedded microchannels and overhanging microstructures on Si/SiO2 substrates

The feasibility of fabricating buried (embedded or subsurface) microstructures between silicon and silicon oxide using laser-assisted chemical etching (LACE) in chlorine atmosphere is demonstrated in this article. An associated LACE ablation model and sample calculations based on one-dimensional thermal analysis and chemical kinetics are presented. A strategy for optimizing the laser process for 3D micromachining is outlined. Potential applications of such fabricated microstructures include microfluidic MEMS for transducers and electronic cooling.