Sub-100 nm Patterning Process and Adhesion Force Simulation in UV-Nanoimprint Lithography

This paper provides a nano-scale simulation model to study the UV nanoimprint lithography. Simulation of molecular dynamic is used to calculate the interfacial stress between the mold and pattern-transfer-polymer layer. Energy minimization was performed to find the equilibrium molecule configuration of the material system using the ensemble of the constant number of particles, constant-volume and constant temperature (NVT) at room temperature. A tensile displacement is applied on the molecular model in each simulation cycle and the displacement is maintained by the time interval for the relaxation of free energy. The tensile displacement is adding to the model repeatedly until interface is completely separated. By monitoring and recording the atomic configurations and energies of the system for each simulation cycle during the simulations, the stress-displacement curve is achieved. To test and verify the simulation model, a nano-patterning process which has a resolution down to 70 nm is demonstrated. The process is based on UV nanoimprint lithography and suitable for both rigid and flexible substrates. An anti-sticking coating reduce the adhesion force and provides the improvement in yield. Detail process flow, including mold fabrication, is described. Si wafers was used as substrates material in the research. From the observation in SEM images, patterns with nano-scale feature size are transferred clearly to the substrates.