PHOTORESISTS BASED ON A NOVEL PHOTOREARRANGEMENT OF O-NITROBENZYLIC POLYMERS

A new photosensitive dicarboxylic acid, isophthalimido bis(alpha-methy lamino-2-nitro-4-toluic acid) (4) was synthesized and characterized. C opolymerization of the corresponding acid chloride with diamines gave polyamides having photosensitive o-nitrobenzylic chromophores at symme trical positions of every repeating unit. Photolysis of the new polyam ides resulted an interesting photorearrangement leading to the formati on of azo polymers with carboxylic acid groups at the ortho positions. The polarity difference induced by the photorearrangement brings abou t a solubility difference between the irradiated and unirradiated poly mers, which renders them useful as positive photoresist materials.