Abstract
A copolymer of t-butyl 5-norbonene-2-carboxylate, 2-(2-methoxyethoxy)ethyl 5-norbornene-2-carboxylate, norbonene, and malefic 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 substrate without causing cross-linking, and shelf life stability of resist. The resist formulated with the polymer shows better adhesion to a silicon substrate as the mole fraction of 2-(2-methoxyethoxy)ethyl 5-norbornene-2-carboxylate increases. Sub-0.15μm line and space patterns were obtained at a dose of 10.5mJ cm-2 using an ArF excimer laser stepper.
