Selective ultrasonic imprinting for micropattern replication on predefined area

• Selective ultrasonic imprinting is developed to replicate micropatterns on predefined areas.
• A profiled mask film is inserted between a target film and an ultrasonic horn.
• Ultrasonic waves are selectively transferred to the target film through the mask film.
• Temperature increase and material softening are concentrated in the masked region.
• Selective imprinting can be applied to micropattern replications on arbitrarily profiled areas.

Conventional micro/nano patterning processes generally use rectangular patterned molds, so that the pattern replications are usually performed in a corresponding rectangular region. In this study, a selective patterning method based on ultrasonic imprinting is developed to replicate micropatterns on predefined areas with arbitrary profiles. To replicate micropatterns on predefined areas, the conventional ultrasonic imprinting process is modified by placing a profiled metal mask between a target film and an ultrasonic horn. Ultrasonic waves are then selectively transferred to the target film through the mask film, from which micropatterns can be replicated onto the predefined areas. For the implementation of the proposed selective imprinting process, the effects of the mask size and shape are experimentally investigated in terms of the replication characteristics of micropatterns. This selective imprinting process is further applied to micropattern replications on arbitrarily profiled areas. In these applications, the effects of the mask film and imprinting conditions are also discussed in terms of the replication quality in both the masked and the unmasked regions.