PFAS free materials and resist for ArF immersion photolithography

The development of PFAS (Per- and Polyfluoroalkyl Substances)-free compounds is crucial for realizing sustainable semiconductor manufacturing processes. In this study, we present PFAS-free materials and resist for ArF immersion photolithography. Newly designed PFAS-free Photo Acid Generators (PAGs) demonstrate comparable sensitivity and solubility change of the resist polymer to existing PAGs. Additionally, the immersion barrier polymer, essential for immersion lithography, exhibits high receding contact angle and TMAH solubility sufficient to function as the resist material. Using these materials, we conducted patterning tests on the PFAS-free resist currently under development at imec with an ArF immersion scanner. The result showed that at a dose of 21-27 mJ/cm², CD 51-53 nm lines were successfully patterned. These advancements have enabled the successful formulation of PFAS-free ArF immersion resists, which have competitive patterning performance.