Title: 3D patterning - from binary structures to continuous topographies
Abstract: The origination of 3D surface topographies presents a challenge in a world of lithography where binary patterns are dominant. Applications in optics often require structures with concave and convex shapes or in microfluidics and biomimetics with asymmetric tapered elements. Grayscale lithography has proven capabilities but often suffers from roughness, lack of degrees of freedom or throughput. At PSI we have developed dose variable electron beam lithography combined with thermally activated selective topography equilibration into a technique which allows fabricating topographical structures with binary, sloped, convex and concave shapes. Simulations using a soapfilm based model enable to predict the reflow of polymer at temperatures only slightly above the glass transition temperature of the exposed polymer. In my talk I will present the current status of 3D lithography at PSI and potential applications.