In house synthesized mixed derivatives containing at least two carbocycles per molecule from the group of anthracenes, adamantanes and steroids with functionalized carbon chains are used as modifiers of resist properties. and especially etch resistance enhancement, and absorption characteristics. Etch resistance enhancement is demonstrated in oxygen, fluorine, and chlorine-containing plasmas under reactive ion etching and inductively coupled plasma etching conditions for poly(methyl methacrylate) and a chemically amplified, positive-tone, methacrylate-based 193 nm photoresist formulation; High resolution experiments show that the proposed additives do not adversely affect the lithographic properties of the photoresists. The additive role is explained with empirical etch parameters such as the Ohnishi number and the ring parameter. (C) 2003 American Vacuum Society.