Advanced polymers and resists - A key to the development of nanoimprint lithography

Abstract

In thermal nanoimprint lithography (NIL), nanometre scale features of a stamp are embossed into a thin polymer layer, which has been heated above its glass transition temperature (Tg). In the development of NIL polymer materials have been playing a key role. Process parameters such as imprint temperature, time and pressure depend on the thermomechanical properties of the polymers. High etch resistance is important for transferring nanometre scale imprinted patterns into a substrate. A survey on polymer systems specifically designed for NIL is given. Thermoplastic methacrylate-based homopolymers and copolymers have been prepared differing in their chemical composition and molecular weights, thermal and flow properties and exhibiting excellent plasma etch resistance. Curing polymers enable nanoimprinting at moderate temperatures. Macromolecular networks are formed by thermal or photochemical crosslinking. In the first case crosslinking occurs during imprinting, in the second one, imprinting and network formation can be conducted in separate steps. The thermal properties of curing polymers can be controlled by the imprint conditions. © 2005 TAPJ.