Rafael Abargues - Charge dissipation in e-beam lithography with Novolak-based conducting polymer films

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      Publication Details (including relevant citation   information):

      R Abargues, U Nickel, P J Rodriguez-Canto (2008) NANOTECHNOLOGY   19: 12.

      Abstract:

      Charging of common resist materials during electron beam (e-beam)   writing leads to deflection of the electron beam path, which can   result in significant pattern displacement. Here we report a new   conducting polymer to eliminate charging. A common approach is to   place the conducting layer underneath the e- beam resist layer.   Conductivity equal or greater than 10(-4) S cm(-1) has been   reported to prevent pattern displacement. Some other properties   such as a flat surface layer, chemical inertness and insolubility   in both the top resist solvent and the developer are also   necessary. The way to achieve all these properties consisted in   synthesizing a conducting polymer inside an insulating polymer to   form an interpenetrating polymer network (IPN) which could   combine their properties. Novolak was used as the host polymer   and terthiophene (3T) as the monomer to polymerize. Cu(ClO4)(2)   initiates simultaneously the oxidative polymerization of the 3T   and its subsequent doping inside Novolak during the bake step in   a one-step reaction. Solvent-resistant and homogeneous conducting   films with smooth surfaces were achieved. The conductivity was of   the order of 10(-2) S cm(-1). Patterning of the top resist was   carried out without disturbing its lithographic performance.

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