Finite Element Analysis of Room Temperature Nanoimprint Lithography Process with Rate Dependent Plasticity

Nanoimprint lithography (NIL) process at the room temperature has been proposed newly to achieve the shape accuracy and to overcome the sticking problem induced in conventional NIL processes. Success of the room temperature NIL relies on the complete understanding of the mechanical behavior of the polymer. Since a conventional NIL process has to heat a polymer above the glass transition temperature to deform the physical shape of the polymer with a mold pattern, visco-elastic properties of the polymer have major effect on the NIL process. The rate dependent behavior of the polymer is also important in the room temperature NIL process because a mold is rapidly pressed onto the polymer while there has been no study on the rate-dependent NIL process. In this paper, finite element analysis of the room temperature NIL process is performed with the consideration of the strain-rate dependent behavior of the polymer. The analyses with the variation of the imprinting speed and the imprinting pattern are carried out in order to investigate the effect of the process parameters on the room temperature NIL process. The analysis results show that the deformed shape and the imprinting force are diversified with the variation of the imprinting speed due to the dynamic behavior of the polymer with the rate dependent plasticity model. The results provide a guideline to determine the process conditions in the room temperature NIL process.