RADIATION-INDUCED REACTIONS OF RING-SUBSTITUTED POLYSTYRENES ANALYZED BY RADIOLYSIS OF LOW MOLECULAR-WEIGHT MODEL COMPOUNDS.

Radiation-induced reactions of polystyrene derivatives are studied by the radiolysis of ring-substituted isopropylbenzene derivatives, i. e. , 4-amino, 4-hydroxy, 4-methoxy, 4-methyl, 4-chloromethyl, 4-chloro and 4-acetyl derivatives. Based on low-temperature ESR analysis and gas chromatographic-mass spectrometric analysis on products, the reaction mechanism is proposed. Based on the clarified reaction mechanism, the design of polystyrene derivatives as resist materials is discussed and two new types of resist systems are described. One is a new chloromethylstyrene based blend resist, which is formulated from poly(4-methoxystyrene) and poly(4-chloromethylstyrene). The other is a new non-swelling alkaline developable negative resist, which is formulated from poly(4-hydroxystyrene) and a chlorine-releasing compound.