Development and characterization of silane antisticking layers on nickel-based stamps designed for nanoimprint lithography

In this study we will report on the development of a process to establish antisticking layers on nickel-based stamps, which are used in several industrial applications of nanoimprint lithography or related methods. The fluorinated alkyl silane films have been deposited onto different Ni-based stamp surfaces in order to minimize the adhesion tendency at the stamp/polymer interface. Film thickness, chemical composition, purity, and binding mechanisms of the silane groups to different stamp surface materials have been determined by photoelectron spectroscopy (XPS). In the case of electroplated nickel stamps—where low imprint qualities are observed—multilayer thick films cover the stamp surfaces, consisting of polymerized, cross-linked alkyl silanes, which are poorly bound to the surface. In order to overcome these restrictions a 100 A thick polycrystalline titanium layer has been established in a sandwich position between the nickel substrate and the silane film. Here, silane film thicknesses in the monomolecular region together with evidences for strong covalent linkage between the silane groups and the oxidized Ti surface can be concluded from the XPS results, leading to film properties and imprint qualities, which are comparable to those formerly observed for silicon stamps.