Microelectronic Engineering 57–58 (2001) 375–380 www.elsevier.com / locate / mee Nanofabrication using hot embossing lithography and electroforming * L.J. Heyderman , H. Schift, C. David, B. Ketterer, M. Auf der Maur, J. Gobrecht Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland Abstract We demonstrate various nano- and microstructuring possibilities of electroforming in combination with hot embossing lithography. Periodic structures down to 120 nm and feature sizes , 50 nm have been replicated. Electrode devices were fabricated with various line widths and heights. The electrodes have a length of several mm, are defect-free over an area of some square mm and have a gapwidth down to 50 nm. Overplating provided a means to increase aspect ratios and decrease gapwidths. Daughter molds were fabricated by backplating structures, forming a substantial supporting substrate. The replicated stamps could be produced with nanoscale fidelity.  2001 Elsevier Science B.V. All rights reserved. Keywords: Electroforming; Hot embossing; Nanoimprint lithography; Molding; Replication 1. Introduction Hot embossing lithography (HEL), also referred to as nanoimprint lithography (NIL), can be used to replicate micro- and nanostructures for a variety of applications, for example interdigitated electrode structures, Fresnel zone plates and high density magnetic recording media [1–3]. One of the main advantages of conformal molding over other replication techniques, such as micro-contact printing [4], is that structures with high aspect ratios can be directly reproduced by embossing a thermoplastic material. This advantage is often lost if as the post processing step, e.g. for pattern transfer into a metal structure, lift-off is used. Electroforming provides a good alternative to the lift-off process because metal structures can be generated with a considerable height and a good surface quality. In addition, electroforming is a more suitable pattern transfer process for areas with a high density of small features, where lift-off tends to result in a large number of defects. In this work we demonstrate the replication of micro- and nanostructures and the fabrication of large area electrodes using HEL in combination with electroforming. In addition, we show that overplating provides a means to obtain higher aspect ratio structures and to fabricate daughter molds in metal. *Corresponding author. E-mail address: laura.heyderman@psi.ch (L.J. Heyderman). 0167-9317 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S0167-9317(01)00436-1