Epoxy-siloxane Low Viscosity Pre-polymer for Nanoimprint Process

Nanoimprint lithography technologies (NIL), introduced by Chou et al. in 1995 [1], may be used to overcome the feature size limitation encountered in classical photolithography while remaining more economical than lithographies based on electron, ion beam, x-ray, and scanning probe tips. In the approach involving hot-embossing of a thermoplastic resist layer, a sub-10nm [2] resolution has been achieved, but difficulties, due to polymer flow, have also been identified with the replication of large patterns [3], the use of negative moulds (with a large protruding surface) [4], and the minimization of residual thickness. However, owing to the high viscosity of the thermoplastic resist, even well above glass temperature (Tg), high pressures between 50 bar and 100 bar [5] are needed. These conditions increase the risk of deformation or damage to flimsy substrates, and they may affect predefined structures in a multilevel lithography process thus becoming detrimental to potential applications. Alternative to hot-embossing: a low pressure, moderate temperature imprint process is presented, based on moulding low viscosity prepolymer materials. The benefits of this type of prepolymer will be reported.