Fabrication and characterization of nanostructures fabricated by nanoimprint lithography

Abstract

Nanoimprint lithography (NIL) is a powerful technique widely used for the fabrication of nanostructures thanks to its budget-friendly and high-throughput process. The fabrication process involves the replication of a nanoscale structure from a mold onto a polymeric substrate called resist. Therefore, it provides the possibility of parallel imprinting with simple equipment of multiple nanostructures based on the stamp design (1). Often, NIL is combined with diverse metal deposition and lift-off techniques in order to transform these nanostructures into functional nanoparticles. Tailored to specific functions and properties, these nanoparticles can be produced with different materials, but their geometry depends primarily on the resolution of the nanostructures. Before the imprint process itself, multiple parameters need optimization for the successful transfer of high-resolution patterns.This work highlights first the crucial role of the anti-sticking method during the manufacturing of the negative and positive replicas of the nanostructures. We present an experimental protocol for reducing the surface energy based on contact angle measurements.Furthermore, a working stamp needs to be produced considering different aspects like being compatible with the resist but mostly being flexible and solid at the same time to preserve the structure for multiple imprints.In addition, this research investigates the capability of NIL to replicate a variety of geometries across different scales. Elliptical nanostructures ranging from 250nm to 30nm and a circular nanostructure with an 80nm diameter were fabricated, with a high aspect ratio. This demonstrate the versatility of NIL for high-throughput production of nanostructures, even for smaller sizes.To conclude, this research definitively establishes the efficacy of NIL in the context of largescale nanostructure manufacturing. The optimization of the anti-sticking method and the successful replication of diverse nanostructures at various scales showcase the potential of NILfor diverse nanotechnology applications.