Replication of polymeric micro patterns by rapid thermal pressing with induction heating apparatus

Hot embossing, one of nanoimprint lithography(NIL) techniques, has been getting attention as an alternative candidate of next generation patterning technologies by the advantages of simplicity and low cost compared to conventional photolithographies. A typical hot embossing usually, however, takes more than ten minutes for one cycle of the process because of a long thermal cycling. Over the last few years a number of studies have been made to reduce the cycle time for hot embossing or similar patterning processes. The target of this research is to develop an induction heating apparatus for heating a micro patterning mold at high speed with the uniformity of temperature distribution. It was found that a 0.5 mm-thick nickel mold can be heated from 25degC to 150degC within 1.8 seconds with the temperature variation of plusmn10degC in 4-inch diameter area, using the induction heating apparatus. Micro patterns of 120 mum line width and 25 mum height were successfully replicated on a plastic sheet under the pressure of about 0.09 MPa within 60 seconds.