ESPACER, water-soluble polythiophene derivative

IBM introduced a family of polyanilines, referred to as PanAquas , which are highly soluble in neutral water in the conducting form. The PanAqua provides a simple and effective discharge layer for e-beam lithography and can be cleanly removed during the alkaline development of the resist. A water-soluble polythiophene derivative referred to as ESPACER (a trade mark and product of Showa Denko K. K.) is also very effective at eliminating resist charging and can be removed by water wash. 

Recently, this polythiophene derivative was evaluated as a topcoat discharge layer that was applied to a typical novolac resist [26]. The polymer was found to be very effective at eliminating resist charging. In another study [71], a water-soluble polythiophene derivative referred to as ESPACER was applied to a chemically amplified resist, and charging was eliminated during e-beam writing. In this system, the ESPACER was removed by a water wash prior to the development of the resist. 

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