为了探寻准分子激光电化学刻蚀硅工艺中的热-力效应特性,采用功率密度大的248nm准分子激光聚焦照射浸在KOH溶液中的n—si表面,实现了一种激光电化学复合刻蚀工艺。通过数值仿真与实验比较的方法,对该工艺的刻蚀速率进行了分析。研究结果表明,该复合工艺存在激光直接刻蚀、电化学刻蚀和激光与电化学耦合刻蚀等三种刻蚀作用;在耦合作用中,溶液中激光加工的热效应较小,光热效应导致的刻蚀小;而溶液中激光加工的力学效应对材料的刻蚀作用很大。通过对准分子激光与溶液中靶材相互作用过程的热-力效应分析,更深入地探讨了准分子激光电化学工艺的刻蚀机理。
In order to further understand thermal-mechanical effect of laser-induced electrochemical etching process, the experiments of micromaehining silicon by laser-induced electrochemical etching are carried out. This paper adopts 248nm excimer laser as light source and uses KOH solution as electrolyte. The etching rate is analyzed in detail by numerical simulation and experiments. It is verified that compound technics is made up of laser etching, electrochemical etching and coupling etching. In the coupling effects, the thermal effect is little and the etching induced by thermal effect is little. The mechanical effect of laser micromachining in liquid has great effect on material etching. By the study of thermal-mechanical effect during short-pulse exci- mer laser interacting with matter in liquid, the mechanism of the coupling process was further understood.