Photosensitive polymers bearing iminooxysulfonyl groups. A water soluble positive‐type photoresist

Photosensitive polymers were synthesized by the copolymerization of 4‐(9‐fluorenylideneiminooxysulfonyl)styrene (1) with 2‐dimethylaminoethyl methacrylate (2), 2‐diethylaminoethyl methacrylate (3), or methacrylic acid (4). On irradiation with UV light the decomposition of monomeric units of 1 (A) in the polymers led to the formation of sulfo groups in their side chain. Although the quantum yield of photodecomposition of units A was found to be independent of the fraction of units A in the copolymers, it is dependent on the polymer structure in the film. Effects of the fraction of units A in the copolymers and of the polymer structure on the photoinduced dissolution of the polymers in water were studied.