Degradation behavior of release layers for nanoimprint lithography formed on atomically flat Si(111) terraces

摘要

A release layer for nanoimprint lithography was formed on atomically flat Si(111) terraces to investigate its surface morphology and degradation behavior due to imprinting. The adhesive nature between the layers and a polystyrene colloid probe was also evaluated. Three types of release layers (silicone, fluoro-oligomer, and perfluoropolyether) were formed on mildly oxidized Si(111) substrates that retained a flat terrace structure. All the layers were sufficiently thin and uniform to show the flat terrace structure of the Si(111) substrates. These release layers showed different degradation behaviors toward thermal nanoimprint lithography and UV-photocure nanoimprint lithography cycles as elucidated by x-ray photoelectron spectroscopy, atomic force microscopy, and adhesion force measurements. The perfluoropolyether exhibited better durability against nanoimprint cycles due to the presence of free molecules not bound to the surface. This study includes a detailed discussion of the degradation mechanisms of the release layers.