Synthesis and characterization of positive photosensitive polyimide precursors

This paper is concerned with the study of the positive photosensitive polyimide precursors, and deals with monomer synthesis, polymerization, and characterization. The polymers were prepared from diamines and diaeid chlorides whieh were derived from the reactant with biphenyltetracarboxilic dianhydride and o-nitrobenzyl alcohol. The molecular weights of the polymer were controlled by adjusting the monomer stoichiometry. The photoreaction of the polymers was confirmed from the change in IR spectra between the film exposed and unexposed to UV light from a HgXe lamp. The exposed areas of the film dissolved in alkaline solution, forming the positive tones. There was a marked difference in sensitivity between the polymers having different molecular weights. Their sensitivities decrease as their molecular weights increase. Further, there was a difference in the thermal behavior. Imidization temperature was shifted to a high temperature side and thermal stabilities increased with an increase in molecular weight.