Replication of deep x-ray lithography fabricated microstructures through casting of soft material

We introduce simple double-casting replication methods for high-aspect-ratio microstructures fabricated by deep x-ray lithography using intermediate molds of soft materials. Two types of soft material are investigated. The ability to fabricate polymethylsiloxane (PDMS) molds with well-type structures with aspect ratios up to 35: 1 is demonstrated for structure densities below 50%, and the reproduction from this mold of pillar-type polymethyl methacrylate (PMMA) structures with aspect ratios of 20: 1 is achieved. Polyvinyl alcohol (PVA), a water soluble polymer, is also tested as a sacrificial intermediate mold and successfully used for the replication of structures with aspect ratios up to 5:1. Double-casting replication methods are described and discussed for their potential improvement. (c) 2006 Society of Photo-Optical Instrumentation Engineers.