Isothermes Heißprägen von beschichteten Glaswafern
Isothermal hot-embossing of coated glass wafers
Hot-embossing is an economical manufacturing process for the structuring of glass. For structures with dimensions in the millimetre and micrometre range and high aspect ratios it is necessary to work under isothermal process conditions. In order to prevent the sticking of the glass to the tool, the glass substrates were coated with thin metal, carbon and oxide layers. The layers were examined with respect to their behaviour change and suitability for the embossing process. All layers showed a clear reduction of the adhesive forces and a shift of the sticking temperature to higher temperature ranges. Some layers led even to the abolition of any sticking in the entire viscosity range relevant for the hot-embossing of glass. The examined layers behave ductile with small strains, however, under larger elongations tend to cracking. Fluidic demonstration structures were realized and hot-embossed successfully in float glass. The lateral design geometries of the channels and chambers lay between 10 µm and 2 mm with embossing depths up to 2 mm. The largest aspect ratio of embossing depth to structural width amounted to 3. The attainable accuracies and surface qualities correspond thereby to that of the used mould insert. The results of the research show the extraordinary potential of the new coating strategy for the hot-embossing of glass.