High molecular weight polystyrene as very sensitive electron beam resist

► We studied electron beam exposure properties of high molecular weight polystyrene. ► Its sensitivity increases linearly with molecular weight. ► For 900 kg/mol, the sensitivity is 1.1 μC/cm2 when exposed at 2 keV. ► The sensitivity is one order higher than PMMA and ZEP-520A. ► Line array patterns of 100 nm half pitch can be well defined in polystyrene.