Adhesion-promoted copolymers for 193-nm photoresists without cross-linking during lithographic process

摘要

A copolymer of t-butyl 5-norbornene-2-carboxylate, 2-(2-methoxyethoxy)ethyl 5-orbornene-2-carboxylate, norbornene, and maleic anhydride was synthesized as a matrix polymer for ArF excimer laser lithography. Hydrophilic 2-(2-methoxyethoxy)ethyl ester groups are introduced into side chains of the matrix polymer in order to improve adhesion to a silicon substrte without causing cross-linking, and shelf life stability of resist. The resist formulated with the polymer shows better adhesion to a silicon substrte as the mole fraction of 2-(2-methoxyethoxy)ethyl 5-norborneen-2-carboxylate increases. Sub-0.15#mu#m line and space patterns were obtained at a dose of 10.5 mJ cm~(_2) using an ArF excimer laser stepper.