A Nanoimprint Lithography Hybrid Photoresist Based on the Thiol-Ene System

A novel hybrid resist for UV nanoimprint lithography (UV-NIL) based on the thiol-ene photopolymerization is presented. Our system comprises mercaptopropyl polyhedral oligomeric silsesquioxane and benzyl methacrylate, with trimethylolpropane trimethacrylate as the crosslinker. The obtained hybrid resists possess a variety of characteristics desirable for UV-NIL, such as low viscosity (6.1-25 cP), low bulk-volumetric shrinkage (5.3%), high Young's modulus (0.9-5.2 GPa), high thermal stability, and excellent dry-etch resistance. Based on these performances, the optimized components are evaluated as UV-NIL resists. The result is a high-resolution pattern with feature sizes in the range of 100 nm to several microns. The double-layer resist approach is used for pattern transfer into silicon substrates. The excellent oxygen-etch resistance of the barrier material enables a final transfer pattern that is about three times higher than that of the original NIL mold.