Theoretical Estimation of Absoption Coefficients of Various Polymers at 13 nm

摘要

The linear absopiton coefficinents at 13 nm were calculated for more than 150 polymers. The results indicate that an aromatic substitution lowers the absorption coefficient. This is because oxygen hjas a larger atomic absoption than carbon or hydrogen and the substitution reduces the realtive oxygen content. Furthermore, hte Oh nishi parameters for the poymers were calculated in order to investigate the relationship bewtween the a bsorption at 13 nm and the etching resistance. This showed that polymers with aromatic groups toend to exhibit a woer absorptionn and a hgiher etching resistnace than those without aromatic groups. This suggests that, regrarding resist processes for EUV (extreme ultraviolet) lithography, a single-layeer resist process employing no hard-mask layer is another promising candidate in addition to one that uses both an unltrathin resist layer ( ￣100 nm thin) and a hard-mask ayer