Composite coating materials for the hot embossing of microoptical components in inorganic glasses

In future technologies of telecommunication and laser techniques there is a high demand on microoptical components having aspherical or fresnel- and grid-shaped surfaces. For many of these components the strong requirements concerning optical quality and long term stability can only be reached if high quality inorganic glasses, instead of plastic materials, are applied. A key for enabling the fabrication of these components by low cost moulding and hot embossing processes are coating materials for the forming tools which prevent the sticking between tool and glass. These coatings, however, must not impede the reproducing of the submicron scale-structures prepared, prior to deposition, in the substrates. In the present investigation composite coatings from the systems of ceramic materials were deposited on different kinds of tool materials. Rf-magnetron sputter and ion beam deposition techniques were applied to prepare coatings in nanoscale composite or superlattice structures. The properties of the coatings and the behaviour of coated toolsmoulds were investigated and hot embossing experiments were performed at temperatures of 600°C and higher. Results obtained will be discussed and examples for the hot embossing of components like micro lens arrays and diffractive beam shapers will be presented.