Study of Nanoscale Surface Profile Fabrication by Atomic Force Microscope Technique

• Main Authors: Ping-Chen Chen, 陳品誠
• Other Authors: Chau-Shioung Yeh
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/55203432089046004533

碩士 === 國立臺灣大學 === 應用力學研究所 === 90 === With an attempt to understand and develop nanostructure fabrication and application for liquid crystal display systems about alignment layer and optical films, an atomic force microscope technique was used in this dissertation. A polyimide layer (AL12G) was successfully turned into an alignment layer that has the potential to be used in making a liquid crystal display by using the scratching actions exerted by the tip of an atomic force microscope system. The alignment mechanism of liquid crystals on polyimide surface was not only the microgrooves effect but also the interaction force of liquid crystal molecules. Furthermore, the spacing of microgrooves was also a significant factor that influenced the alignment consequence. The experimental results indicated that in the 100µm by 100µm square area, grooves of 0.5µm, 1µm, 2µm, and 4µm spacing were all found to be straight and the profiles imprinted by the atomic force microscope were also found to be stable. The liquid crystal cell was studied by polarizing optical microscopy and the alignment layer was investigated by reflection ellipsometry (PI-Checker) could prove that grooves of 0.5µm, 1µm, 2µm spacing were led to good alignment effect but grooves of 4 µm spacing was not. The experimental results obtained thus implied that the mechanism proposed in this article could lead to a novel alignment layer fabrication algorithm in the future. Another nanostructure was successfully fabricated using atomic force microscopy and anisotropic etching. Si(110) surfaces have been oxidized at nanometer scale with electric field enhanced oxidation using a conducting probe with externally applied a bias voltage, which leads to the completed minimum oxidation grating period of 0.1 µm. The oxidation grating served as an effective mask for pattern transfer into the substrate by wet chemical etching was successfully done and the maximum silicon grating area achieved 70µm by 70µm and the minimum silicon-grating period obtained 0.3 µm. The parameters setting and fabrication process of the nanometer scale surface structures have been established successfully in this thesis. Besides, the optical analysis about the application of nano-grating has been finished and the theoretically investigation of two feasible cases was studied as well.