Scaling up the sub-50 nm-resolution roll-to-roll nanoimprint lithography process via large-area tiling of flexible molds and uniform linear UV curing

While roll-to-roll nanoimprint lithography (R2R NIL) can be capitalized in highly scalable fabrication of nanopatterns, preparation of large-area flexible molds remains the main challenge. In this work, we demonstrate that tiling of small-area nanopatterns in a slightly overlapped fashion can provide a practical solution to it; sequentially performing the UV NIL processes onto self-replicable UV-curable resin drops by using a small tile mold can create large-area-tiled molds. We systematically investigated that controlling the tile NIL force and several parameters is crucial to minimize the seams between tiles. We also present that the R2R NIL system can be improved by integrating a linear UV LED module for prompt UV curing before the as-imprinted nanopattern reflows, which is critical for high-resolution, high-quality nanopatterning. By using the tiled mold containing 45 nm-half-pitch nanogratings and operating the UV LED-integrated R2R NIL system, we exemplify that sub 50 nm-resolution nanopatterns can be faithfully created.