Fabrication of roll mold using electron-beam direct writing and metal lift-off process
Roll-to-roll nanoimprint lithography (RTR-NIL) has received considerable attention as a potential solution for large-area nanopatterning with simultaneous high resolution and throughput. However, progress in RTR-NIL is restricted by the difficulty of fabricating nanoscale roll molds. For example, a seamless roll mold is ideal since seams result in lower product yield. To produce a seamless roll mold with the desired nanopatterns, we previously developed a technique that uses an electron beam (EB) for direct writing onto a rotating cylindrical substrate. However, the EB resist is typically made of soft polymer materials and is not sufficiently tough to withstand RTR-NIL. Thus, after development of the EB resist, a pattern transfer process such as dry etching or metal deposition and lift-off is necessary, but dry etching of the roll substrate is difficult because the substrate must rotate in plasma ambient. Therefore, we used the metal lift-off process to fabricate seamless metal-patterned roll molds, with which we successfully achieved RTR-NIL.
roll mold lift-off process roll-to-roll nanoimprint electron beam lithography metal patterning