Radiation‐Induced Reactions of Chloromethylstyrene‐Based Resist Materials Analyzed from Radiolysis of Low Molecular Model Compounds

Abstract

The radiation‐induced reactions of chloromethylstyrene‐based resist materials are studied by low temperature ESR and gas chromatography‐mass spectrometry (GC‐MS) analyses using low molecular model compounds. Low temperature ESR analyses indicate that main radiation‐induced active species in the initial stage of the reaction are benzyl radicals formed through chlorine removal from chloromethylstyrene units and simultaneously produced active chlorines. The amount of the α radicals formed through α‐hydrogen cleavage is less than one‐tenth that of the benzyl radicals. GC‐MS analyses indicate that large amounts of α radicals are produced through the subsequently occurring hydrogen abstractions by radiation‐induced active chlorines. The susceptibilities of individual constituents to hydrogen abstractions are determind as 6.2 for a methylstyrene unit, 2.6 for a styrene unit, and 1 for a chloromethylstyrene unit.