New types of soft lithography: Materials patterning and device application

Abstract

We describe a novel technique for fabricating submicron-sized polydimethylsiloxane (PDMS) resist patterns on electronic material substrates using decal transfer lithography (DTL) in conjunction with reactive ion-beam etching (RIE). An O2/CF4 gas mixture is used to etch a supporting PDMS thin-film that resides atop a closed-form decal polymer to reveal conventional resist structures. These structures further provide an effective latent image that can, in turn, provide for an extension of soft-lithography as a form of multilayer lithography - one yielding sub-micron structures similar to those obtained from the conventional photochemical methods used to prepare such resists. Specifically, the combined DTL/RIE patterning procedure was found to be compatible with commercially available planazation layers, and provides a direct means for preparing high aspect ratio resist features. We further illustrate the applicability of this new form of soft-lithography for fabricating electronic devices, describing model silicon-based thin-film transistors fabricated using silicon-on-insulator (SOI) wafer technology.