Nano-sized silver patterning using nano-ink with an indirect patterning method of nanoimprint and lift-off processes

Silver nanopatterns were fabricated using a nanoimprint and lift-off process using silver nano-ink. Particle-based silver nano-ink was used to fabricate metal patterns below 100 nm in a lift-off process without the undercut shape of polymer patterns typically required in a conventional lift-off process using evaporated metal. The silver film made by spin-coating the silver nano-ink and removing the solvent using PDMS, has a low density compared to evaporated metal film; hence, unnecessary nano-ink that is not part of the pattern area is easily eliminated during the lift-off process. Using the proposed patterning process, patterns defined on a stamp were successfully transferred to the nano-ink through nanoimprinted polymer patterns on a four-inch Si wafer. Compared to other metal patterning methods that involve lift-off processes, the proposed metal patterning process is a simple and cost-effective process capable of fabricating the micro- and nano-sized metal patterns due to its low operating temperature and one-step polymer patterning process by nanoimprinting.