Thermal Roll-to-Roll Imprinted Nanogratings on Plastic Film

A strong need exists for effective nanopatterning technique to fabricate the next generation devices at low cost and high volumes. Nanoimprint lithography (NIL) has received a lot of attention, because of its process simplicity. Roll to Roll nanoimprint (R2RNIL) can be used for optics and electronics, such as wire grid polarizers and transparent conductive sheet. In this study, we have examined R2RNIL high speed patterning of nanogratings on a plastic film. Our mold design consists of nanoscale line and space (LS) pattern. In order to fabricate the nanoscale pattern by using R2RNIL it is very important to understand replication behavior at the nanometer scale to predict the fabricated pattern. We focus on the replication behavior for a cellulose acetate film via thermal R2RNIL. A flexible nickel replica mold was attached to the upper roll, which was be heated to target temperature. We have used the master nanogratings mold with line and space width of a 580 nm and 2160 nm, respectively. The pressure applied from the lower roll by air cylinder was 6.5 MPa. The temperature of the upper roll was varied from 31 to 120 °C when line feeding speed was constant (0.4-0.5 m/min). The Tg of cellulose acetate film (90 ??m thickness) is 120 °C. The heights of the mold and the transferred pattern on the film were measured using atomic force microscopy (AFM, Digital Instrument Co., Dimension 3000)