Ultrasonic Nanoimprint on Poly(ethylene terephthalate) at Room Temperature

Abstract

We have developed a new nanoimprint lithography (NIL) technology employing ultrasonic vibrations generated by a magnetostriction actuator where the process does not require any heating or use of ultraviolet light. In this work, a mold was mounted onto an upper loading stage using a negative-type resist. The mold pattern was then run through “push-into and pull-away” cycles on a molding material by applying longitudinal ultrasonic vibrations. For the molding material, poly(ethylene terephthalate) (PET) was selected because among engineering plastics its glass transition temperature is relatively low. Using this technique we succeeded in imprinting on PET at room temperature and made significant improvement in the throughput. The relationship between the depth of imprinted patterns and the contact force, or the contact time, was investigated by imprint experiments that employed an electroformed-Ni mold with convex patterns. The result of the experiment showed that, in working with ultrasonic NIL, the best contact force and the best contact time depend on the size of the pattern. The ultrasonic NIL technology has the potential of becoming a key technology for carrying out tasks on the scale of mass production.