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 molecular glass resists as high performance resist materials and discussed them on the former talk1. Those novel adamantane based molecular glass resists were made sure of sufficiently high Tg and the highly etch resistance. However some of them were not satisfied as resist materials due to their higher or lower solubility. Then we have designed and synthesized new adamantane based molecular glass resists containing acetal and ester moieties for the lower dose sensitivity and the excellent transparency at 193 nm. Further more, the protecting groups were modified in order to control the solubility into 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 cholic acid moiety in order to improve their film thickness loss by subtrahend and / or by capping the hydroxyl group. These treatments affected their adhesion to a wafer greatly. The capping technique using with any units can introduce various functional 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 EB exposure. Although, the excess subtraction of hydroxyl group has reduced its film property like GR-11 that made from lithocholic 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 B ARCs as the under layer.