Study of Excimer Laser Electrochemical Etching Silicon

To further understand the behavior of laser-induced electrochemical etching process, the experiments of micromachining silicon by laser-induced electrochemical etching were carried out. 248nm excimer laser as light source is adopted in this work with the power of 10⁹W/cm² for the first time and KOH solution is used as electrolyte. Based on the experiment results, the surface images and etching rate are analyzed in detail. It is verified that the compound technique is a combination of laser etching, electrochemical etching and coupling etching, and laser etching is dominating in the compound process. Besides, both liquid-enhanced pressure and jet shock pressure can preferably improve the etching rate. At the same time, the anisotropic etching stop of silicon in alkaline solution is solved in this study. As a result, this process can be applied to transfer pattern without mask, and it possesses the ability of machining large aspect ratio micro structures.