Mold cleaning and fluorinated anti-sticking treatments in nanoimprint lithography

Fluorinated anti-sticking layers (F-ASLs) are generally used to prevent adhesion between molds and resists in nanoimprint lithography (NIL). Nevertheless, these layers are degraded after a certain number of imprints and the mold needs to be cleaned and re-treated. We have observed that the cleaning procedures before re-treatment impacts on the grafting of the fluorinated molecules and on the longevity of the ASL. We propose an efficient cleaning procedure of the damaged anti-sticking layers on both silicon and fused silica molds allowing a reproducible re-deposition. Surface chemistry analyses were conducted using a specific procedure based on X-ray photoelectron spectroscopy (XPS) experiments. This procedure was proven to be suitable for ultra thin organic layer composition analysis.