Large area nanolithographic templates by selective etching of chemically stained block copolymer thin films

Magnetic nanodot arrays were prepared from thin film templates of cylinder-forming polystyrene-polylactide diblock copolymers by first annealing the films to obtain PLA cylinders oriented perpendicular to the surface, then selectively staining the PS matrix with RuO₄ vapors, followed by etching the cylinders by O₂-reactive ion etching. Metal was then deposited by molecular beam deposition and finally the polymer mask was lifted off.