Abstract
This dissertation presents mainly an experimental investigation into the effects of the metallic thin films properties, mold geometries, and process parameters on the formation of nano patterns on metallic thin films by using direct nanoimprint technique. By the application of molecular dynamics simulation, a theoretical study was performed first for the purpose of understanding the formation mechanism of the proposed direct nanoimprint. In the experiment, the silicon mold with nano-scale patterns was fabricated by the direct writing of electron beam lithography and the metallic thin films were prepared by using DC sputtering as well as ion-beam sputtering. For the purpose of studying the effects of the feature size on the formation of nanostructure the mold geometry, herein, was characterized by two non-dimensional parameters: mold-cavity- width-to-pitch (WP) ratio and aspect ratio. The process parameters considered in this study, which could influence the formability and sustainability of the formed pattern, consisted of temperature and pressure holding time. In addition, the characteristics of the thin films discussed herein covered the types of metallic materials and their thicknesses. After the imprint experiment, the pattern transferred results under various geometry and process parameters were observed. Meanwhile, the reciprocal effects existing among the WP ratio, aspect ratio, and the thickness of metallic thin film were also examined. The quality of the formed pattern was evaluated by employing the index of pattern- formation ratio that was defined by the height and width of the formed pattern divided by the corresponding geometries of the mold. Besides, the surface profile of the transferred pattern was also an important index of quality observed herein. Finally, the mold abrasion that could reduce the life of the mold due to wear was examined carefully.