Micro-Fabrication by Using Combination Technique of Nano-scale Machining and Alkaline Etching

利用摩擦力显微镜(FFM)对单晶硅(100)表面进行KOH刻蚀时，加工区域出现了掩蔽效应。本研究对这一现象产生的机理以及利用这一现象制作微结构的方法进行了研究。通过对纳米加工条件的控制，对加工区域进行了分析，发现加工表面下存在一层低结晶层。在第一层以下有晶位错的影响层。结果表明，当KOH溶液浓度小于20wt%时，低结晶层起到掩蔽作用。另一方面，在浓度大于20wt%的KOH溶液中，含有晶体位错的影响层具有增强的刻蚀效果。在刻蚀过程中加入超声波可以改善结构的表面粗糙度和形状。此外，通过控制法向载荷和加工线节距的条件，改变了FFM加工区的掩蔽效果。利用该技术制作了三维微结构。今后将通过加工悬臂梁的开发和工艺条件的优化来研究制造更高精度的结构。

Masking effect was appeared to the processing region when the (100) surface of single crystal silicon processed by using the mechanism of friction force microscope (FFM) was etched by KOH solution. In this research, mechanizm of this phenomenon and method to fabricate the microstructure by utilizing this phenomenon was researched. Moreover, the research to fabricate 3D microstructure was carried out by controlling nano-scale processing conditions.Processing region was analyzed by TEM, Laser Raman spectroscopy and etc. As a result, it was found that there is a low crystalline layer under the processing surface. And there is affected layer with crystal dislocation under the first layer. From these results, masking effect was provided by low crystalline layer when concentration of KOH solution is less than 20 wt%. On the other hand, enhanced etching effect was provided by affected layer with crystal dislocation in higher concentration of KOH solution more than 20 wt%. Surface roughness and shape of structure was improved by addition of ultrasonic wave in etching process. Moreover, masking effect of FFM processing region was changed by controlling the condition of normal load and pitch of processing line. By utilizing this technique, 3D micro-structure was fabricated. In the future, research about fabrication of higher precision structure will be carried out by development of machining cantilever and optimization of processing condition.