Ultrathin Resist Pattern Transfer Process by Filling Mask Material in the Resist Pattern

Abstract

We performed experiments to transfer the pattern of ultrathin resists with the reversal mask process. Resist film thickness was 100 nm for samples using the KrF resist (KrF sample) and the ArF resist (ArF sample), and 70 nm for the sample using the EB resist (EB sample). Resist patterns were formed on an organic film, and then cured by EB. Spin-on-glass (SOG) was coated over the resist patterns and etched back. Finally, we obtained organic film patterns using the remaining SOG as an etch mask. In the case of the KrF sample, it was possible to transfer three resist patterns (lines and spaces (LS), isolated line (iL), isolated space (iS)) to the organic film simultaneously. In case of the ArF sample and the EB sample, it was possible to transfer each pattern. However, the transfers were not simultaneous. In order to transfer different patterns simultaneously, strengthening etch resistance of mask material, improving uniformity of SOG thickness over the resist pattern and suppression of shrinkage of resist pattern thickness caused by EB cure are important to achieve.