| Summary: | 碩士 === 國立清華大學 === 動力機械工程學系 === 94 === The thesis proposes an alternative method which can transfers nano-scale patterns to aluminum (Al) thin films directly. If the template can perfectly reproduce on metallic thin films, then it is called high fidelity patterns and the best quality of nanoimprint. Molecular dynamics simulation is utilized to simulate the nanoimprint process and via examining the atomic stress, the surface effect, substrate effect and stress relaxation are discussed. From the plastic atoms produced by nanoimprint process, the slip system and the springback phenomenon can be observed. The simulations and the experiments are implemented for three parameters, the thickness of the metallic thin film, the mold space to a periodic width and the aspect ratio of the mold-teeth. In the simulation, the effect of nanoimprint quality will be discussed by plastic-atom ratio, filling rate, springback ratio, and pattern-formation ratio. In the experiments, the difference between the pattern on the thin film and on the mold, meant the quality of nanoimprint, is presented by the formed pattern of width and the formed pattern of height.
From the simulation and experimental results, the following phenomena can be observed. When the thickness of the film decreases, the filling rate is lower owing to substrate effect and it induces the worse formed pattern. With increasing the mold space to the periodic width, the filling rate decreases and the formed pattern of height is shorter. But the formed pattern of width is better because of lower stress in the mold space during imprinting. For high aspect ratio mold, the filling rate is lower and the formed pattern is worse.
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