Evaluation of novel resist materials for EUV lithography

In developing high sensitivity extreme ultraviolet (EUV) resists, we focused on the fact that EUV photon absorption by chalcogen atoms is larger than that by carbon or hydrogen atoms. We chose this focus because it is considered that in EUV the absorption of incident radiation by base polymers influences acid generation. To determine the effects of introducing chalcogen atoms into base polymers under EUV exposure on lithography performance, we synthesized novel co-polymers of novel methacylate monomers that included oxygen and sulfur atoms in acid-cleavable moiety as well as polar monomers, and evaluated their sensitivity under EUV and ArF exposure. The sensitivity of polymers that were rich in chalcogen atom content improved more under EUV exposure than under ArF exposure. We also used a highsensitivity quadrupole mass spectrometer (QMS) to observe the outgassing species generated from these polymers under EUV exposure in detail.