Photoacid catalyzed main chain scission of poly(butene-1 sulfone) as a deep UV positive resist

Abstract

Poly(butene-1 sulfone) (PBS), a sensitive e-beam and X-ray resist, is inert to UV light. We found that the addition of a small amount of photoacid, triphenylsulfonium hexafluoroarsenate (TPSHFA), to PBS can catalyze its main chain scission via C-S bond cleavage by 254 nm deep UV exposure and concurrent baking at 80°C. Therefore, PBS can be used as a deep UV positive resist. The chemistry and resist characteristics of the PBS + TPSHFA system are discussed.