Nanometer electron beam lithography with azide-phenolic resin resist systems

High resolution negative electron beam (EB) resists consisting of an aromatic azide and a phenolic resin have been developed for nanometer lithography. Bisazides which crosslink phenolic resins are more suitable for fine pattern fabrication than monoazides. Several phenolic resins such as novolak resin and polyhydroxystyrene were evaluated as resist matrix resins, and poly(p-hyroxystyrene) was selected as the best resin for nanofabrication. A resist composed of 3,3'-dimethoxy-4,4'-diazidobiphenyl and poly(p-hyroxystyrene) enables the definition of a 50 nm line-and-space pattern with an EB dose of 170 mu C/cm(2) under optimum process conditions. The fine resist pattern obtained has sufficient dry etching resistance and can be applied to Si nanofabrication with good critical dimension control.