Fabrication of fine metal patterns using solvent-soluble UV-curable resin

Fine metal patterning at the micro- and nanoscale has become essential for advancing next-generation devices in fields such as MEMS, NEMS, electronics, and biosensors. Traditional approaches, including sacrificial layer technologies using polyvinyl alcohol (PVA) and etching techniques, have significant limitations in terms of patterning accuracy, mechanical stability, and environmental impact. This study introduces a novel approach for high-precision fine metal pattern fabrication by combining nanoimprint lithography (NIL) with lift-off technology using PAK-YY01 resin, a newly developed solvent-soluble UV-curable material from Toyo Gosei Co., Ltd. The experimental methodology involved fabricating master molds using electron beam lithography with a ZEP520A resist, creating replica molds from a UV-curable epoxy resin, transferring patterns to a PAK-YY01 resist, depositing gold films, and performing liftoff processes. Line and space (L&S) patterns with linewidths of 75, 100, and 200 nm were fabricated along with pillar structures from hole patterns with a diameter of 200 nm. Dimensional analysis revealed average transfer errors of 11.25 nm from the mold to the epoxy replica, 44.04 nm from the epoxy to PAK-YY01, and 27.85 nm after lift-off. For patterns exceeding 200 nm, the dimensional errors are minimal, yielding high-fidelity metallic structures. This study demonstrates that PAK-YY01-based NIL combined with lift-off technology offers a viable pathway for fabricating high-precision metal patterns with low environmental impact and high throughput.