UV-assisted nanoimprint lithography: the impact of loading effect in silicon on nanoscale pattern of metalens

This research evaluates the Silicon loading effect from Deep Reactive Ion Etching (DRIE) on UV-nanoimprint lithography (UV-NIL) in nanofeature patterning, essential for cost-effective, high-resolution lithographic applications as highlighted by the International Technology Roadmap for Semiconductors. Focusing on metasurface structure creation via E-beam lithography (EBL) and Bosch DRIE for a silicon master mold, it examines the influence of etching conditions on structure uniformity and quality. Key findings reveal that the Silicon loading effect, which varies pattern feature depth relative to sizes, significantly impacts nanofeature replication, affecting pattern geometry, quality, and photoresist layer thickness. It causes nonuniform polymer pillar heights and incomplete pattern transfers in UV-NIL, emphasizing the need for etching condition optimization to mitigate these effects for successful nanostructure production on pre-structured substrates. This study underscores the critical role of controlling the loading effect in mastering mold fabrication for efficient pattern replication in UV-NIL metasurface applications.