Adamantane-based molecular glass resist for 193-nm lithography

摘要

We have already developed several candidates of future resists using not only monomer but also the molecularglass resists as high performance resist materials and discussed them on the former talk'. Those novel adamantane basedmolecular glass resists were made sure of sufficiently high Tg and the highly etch resistance. However some of themwere not satisfied as resist materials due to their higher or lower solubility. Then we have designed and synthesized newadamantane based molecular glass resists containing acetal and ester moieties for the lower dose sensitivity and theexcellent transparency at 193 nm. Further more, the protecting groups were modified in order to control the solubilityinto both a conventional solvents for the spin on the wafers and a developer.Novel adamantane-based molecular glass resists were modified their polarity of the hydroxyl group of cholicacid moiety in order to improve their film thickness loss by subtrahend and / or by capping the hydroxyl group. Thesetreatments affected their adhesion to a wafer greatly. The capping technique using with any units can introduce variousfunctional groups and applied versatile improvements. GR-14 that were capped their hydroxyl group with acetyl unit was imaged sub 100 nm line and space by the EBexposure. Although, the excess subtraction of hydroxyl group has reduced its film property like GR-11 that made fromlithocholic acid. We made sure that the imperfect resist for its improvement of the film thickness loss such as GR-17,GR-18 and GR-19 was affected by BARCs as the under layer.