Reactivity of Halogenated Resist Polymer with Low-Energy Electrons

In chemically amplified resists, secondary electrons are generated upon exposure to ionizing radiations, such as extreme ultraviolet radiation and electron beam. Acid generators are decomposed mainly through their reaction with these secondary electrons after they lose their energy sufficiently. Therefore, the reaction of polymers with low-energy electrons significantly affects acid generation processes. In this study, the authors evaluated the reactivity of halogenated polymers with low-energy electrons using brominated poly(4-hydroxystyrene) and investigated the relationship between reactivity and acid yield. It was found that the decomposition of the radical anions of polymers is suppressed by >20% owing to the delocalization of excess electrons on the pi-orbital of an aromatic ring. (C) 2009 The Japan Society of Applied Physics