Nanoimprint lithography (NIL) is an emerging patterning technology which shows the capability of fabricating nanostructures on a large scale. It is therefore interesting for low-cost NEMS manufacturing. As schematically shown, a stamp made of single crystalline silicon is pressed into a thermoplastic polymer at a temperature above its glass transition temperature TG. After the cavities of the stamp are filled with the polymer, the stamp is removed at a temperature below TG. The resulting residual layer can be removed by anisotropic dry etching, if necessary. Our goal is first to find suitable process parameters for the existing equipment in CMI and to establish a NIL process line. We have succeeded to replicate structures into thin polymer layers reproducibly with sub-micron feature sizes on a wafer scale. This technology will serve as a basis for a variety of applications and a research tool in the sub-micron range.