Improved Pattern Transfer in Soft Lithography Using Composite Stamps

Composite stamps composed of two layersa stiff layer supported by a flexible layerextend the capabilities of soft lithography to the generation of 50−100-nm features. The preparation of these stamps was adapted from a procedure originally developed by Schmid et al. (Macromolecules 2000, 33, 3042) for microcontact printing. This paper demonstrates how pattern transfer using other soft lithographic techniquesmicromolding in capillaries, microtransfer molding, and phase-shifting lithographycan be improved using two-layer stamps relative to stamps made of Sylgard 184 poly(dimethylsiloxane).