利用飞秒激光辐照结合湿法腐蚀方法制备高纵横比全硅槽的研究

Fabrication of High-Aspect-Ratio All-Silicon Grooves Using Femtosecond Laser Irradiation and Wet Etching

利用飞秒激光辐照结合湿法腐蚀方法,制备了高纵横比硅基狭槽。首先利用透镜聚焦飞秒激光至硅片表面,在硅内部诱导结构变化;再结合氢氟酸(HF)溶液选择性腐蚀去除结构变化区域,从而制备出高纵横比硅基狭槽;最后,通过光学显微镜和扫描电子显微镜对狭槽形貌进行表征,研究了狭槽纵横比对激光加工条件如激光功率、扫描速率和数值孔径的依赖特性。结果表明,激光加工条件对于制备高纵横比硅基狭槽存在最优选择。通过优化激光加工参数,可制备出深度为291μm,纵横比为25.3的硅基狭槽。相对于显微物镜,透镜的工作距离较大,加工过程可以避免镜片污染,且具有成本低,通光孔径大等优点。

A simple method of fabricating high-aspect-ratio all-silicon grooves using lens-focused femtosecond laser irradiation and wet etching is demonstrated. Firstly femtosecond laser is focused on silicon surface to induce structural changes inside silicon. Then laser-induced structural change regions are selectively removed by hydrofluoric acid （HF） etching to form high-aspect-ratio silicon grooves. Finally, optical microscope and a scanning electronic microscope are employed to characterize the morphology of the grooves, respectively. The dependences of the grooves aspect ratios on the laser irradiation parameters, such as the laser average power, scanning velocity and the lens numerical aperture, are investigated. By optimizing the laser irradiation parameters, grooves with depth of 291 μm and aspect ratio of 25.3 are produced. Compared with microscope objective lens，lens owns longer working distance, which can keep it from being polluted by the debris erupting from specimen during laser irradiation. Besides, lens has the advantages of low cost and large aperture.