Photoresist Materials Based on Organometallic-Containing Polysulfones

Soluble 1:1 alternating copolymers of p-tert-butylstyrene, p-(trimethyl silyl)styrene, p-(trimethylgermyl)styrene, and 3-vinylbenzyltrimethylsilane with sulfur dioxide have been synthesized by tert-butylhydroperoxide-initiated copolymerization at T < -60°C. Oxygen plasma etch resistance of poly[p-(trimethyl germyl)styrene sulfone resist is higher than that of poly[p-(trimetylsilyl)styrene sulfone resist by a factor of 4.5, and that of cresol-novolac by a factor of 9. Among the polysulfone resists, poly[p-(trimethylgermyl)styrene sulfone shows the best lithographic characteristics.