US Patent 7998651 Imprint lithography

A method of making an imprint template includes providing a transfer layer on a substrate and providing a layer of imprintable medium on the transfer layer, using a master imprint template to imprint a pattern into the imprintable medium, polymerizing the imprintable medium by exposing it to actinic radiation, then etching the resulting polymer layer, the transfer layer and the substrate such that the imprinted pattern is transferred to the substrate, the substrate thereby becoming an imprint template bearing a pattern which is the inverse of a pattern provided on the master imprint template.