Electron-beam fabrication of nonplanar templates for contact printing

Templates for contact printing applications have been fabricated on convex and concave surfaces using electron-beam lithography. Curved quartz lens blanks, coated with a chrome layer to suppress charging, were spincoated with a layer of polymethylmethacrylate (PMMA). Features were patterned into the PMMA followed by development, pattern transfer into the chrome by wet etch, and reactive-ion etching (RIE) of the chrome masked quartz. Features to 0.3 μm have been patterned and transferred ∼600 nm into the underlying quartz substrate by RIE, with less than a 10% etch depth variation across the sample. The patterned substrate was then used as a template to cast polymer stamps from poly(dimethylsiloxane). This approach provides a convenient method of fabricating curved templates for contact printing.