Positive Working Photosensitive Polyimide: The Effect of Some Properties on Sensitivity

The polymers were prepared from diamines and diacid chlorides which were derived from the reaction product of tetra carboxylic dianhydride and o‐nitrobenzyl alcohol having various substituent groups. The photoreaction of the polymers was confirmed from the change in IR spectra of the film caused by exposure to UV light from a Hg‐Xe lamp. The exposed areas of the film dissolved in basic solution, forming the positive tones. The effect of some properties on sensitivity was investigated. The polymer having a methyl group at the α‐position of o‐nitrobenzyl group showed a higher sensitivity than the other. There was a marked difference in the sensitivity between the polymers having different molecular weights, and their sensitivities decrease as their molecular weights increase. The sensitivity of the polymer was influenced by the concentration of a developer.