Molecular Dynamics Analysis of Formation and Friction on Pattern Replication in Direct Nanoimprint

It is well known that metallic nanostructures can be potentially applied in many fields. Direct nanoimprint features an uncomplicated and efficient fabrication process of the metallic nanostructures. This paper contributes to the investigation of the formation and friction in direct nanoimprint process by utilizing molecular dynamics (MD) simulations. The MD model consists of a silicon mold and an aluminum thin film. For the formability, the phenomenon of springback and mold cavity filling ratio are investigated first under conditions of various imprinting depths and film thicknesses. For the friction, the friction mechanisms induced on the mold are studied subsequently. Since a nickel mold is adopted in many industrial applications, it is also simulated to compare with the silicon mold for the purpose of illustrating the material effect on friction mechanisms. This study explores not only friction mechanisms at different stages of the process but the friction force affected by various geometric configurations of the mold, for example, linewidth-to-pitch ratio and surface roughness. This work also provides the general concept that which force dominates the process force and what percentage of the friction force takes in the imprinting force.