Environmentally friendly patterning of molecular waterwheel (Noria) in supercritical carbon dioxide

Abstract

An environmentally friendly development process using supercritical carbon dioxide (scCO₂) was applied to a novel molecular glass resist made from a molecular waterwheel (‘Noria’), and patterned by electron-beam (EB) lithography. The physical and lithographic properties of a Noria derivative, tert-butoxycarbonyl-protected Noria (‘Noria-BOC’), were examined to evaluate it as a next-generation resist in terms of its solubility, film-forming ability, thermal stability, photosensitivity, and patterning properties. FT-IR spectra and contrast curve studies revealed the good photo-induced deprotection reactivity of Noria-BOC and the excellent negative-tone characteristics of scCO₂ development, respectively. The EB-patterning of Noria-BOC followed by development in scCO₂ gave clear lithographic patterns with sub-100 nm resolution.