Substrate Conformal Imprint Lithography of Functional Materials – Review of a BFS-Project

Substrate conformal imprint lithography (SCIL) is an innovative full wafer scale nanoimprint technology [1] . This sub-micrometer patterning method uses flexible PDMS stamps for the structure transfer. Originally, SCIL technology was developed for the transfer of structures into sol gel materials, which hardened via diffusion of solvents into the PDMS stamp material. The work of Ji et al. [2] showed the extension of SCIL to UV-enhanced SCIL (UV-SCIL). With this new option, UV curable materials can be used as resists for the SCIL-method. For the further development of this powerful technology, SUSS MicroTec and the Fraunhofer Institute for Integrated Systems and Device Technology (IISB) initiated the project “Substrate Conformal Imprint Lithography of Functional Materials” (SILFUMA) which was funded by the “Bayerische Forschungsstiftung” (AZ-864-09). As associated partners, DELO Industrial Adhesives and micro resist technologies sub- stantially supported and strengthened the project. SILFUMA was divided into three main work packages. Purpose of the first work package was the evaluation of purely organic resists for UV-SCIL. Common resists for SCIL or UV-SCIL contain inorganic chemistry [2,3]. This fact limits their suitability for dry etching processes. Furthermore, all common resists for SCIL or UV- SCIL need long curing times (3min – 15min) [2,3] . The advantage of purely organic materials used as etching masks is that they are well suited for standard dry etching processes. As shown, another advantage of UV polymers for UV-SCIL is the significant reduction of curing time compared to commonly used resists. So, using UV curing polymers shortens the overall SCIL process time essentially.