In this study, we experimentally investigated the effects of thin-film properties on metallic pattern formation using a direct nanoimprint process. We focused on determining mechanical properties such as grain size, on analyzing defects and fabrication processes. Aluminum thin films are used as transfer materials, the grain size and microstructures of which can be controlled using different deposition process and parameters. The mechanical properties of thin films can be determined by nanoindentation experiments. Instead of it being used to form structures on polymers, nanoimprint process is used for the fabrication of subwavelength structures on aluminum thin films. Formation height is applied to analyze the formation qualities in the nanoimprint process and is measured by atomic force microscopy (AFM). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are utilized to analyze the surface topography, microstructure, and internal defect of thin films. From the experimental results, the following phenomena are observed. For aluminum films of the same thickness, hardness decreases when grain size increases, a phenomenon called the Hall–Petch effect. When the grain size of the thin films increases, formation height increases because hardness decreases. In this study, the relationships between grain size, hardness and formation height for different fabrication methods are determined. The formability of the metallic thin films can be improved through suitable parameter control.