we present a general technique to modify polymer surfaces using n-hydroxysuccinimide (nhs) funtionalized perfluorophenyl azides (pfpas). thin polystyrene films are spin-coated with a solution containing the nhs pfpa ester and are either uv photolyzed with a dosage of 10 mj sq cm or exposed with a 15 kv electron beam with a dosage between 1 and 75 micrometers / sq cm. the nhs active ester groups become covalently attached to the polymer via photogenerated or electron beam generated, highly reactive nitrene intermediates derived from the pfpa. using this technique we demonstrate that well-defined surface regions can be funtionalized with a minimum observable feature size of 0.5 micrometers and 0.2 micrometers for uv and electron-beam exposure, respectively. through reaction of the functionalized surfaces with primary amine-containing reagents, we have installed biological molecules on the polymer and have measured the activity of an immobilized enzyme. polymers, surface functionalization, deep-uv lithography, immobilization of biological molecules