THE USE OF FT-IR TO CHARACTERIZE PHOTOSENSITIVE THERMOSETS

Photosensitive polymers are used extensively in the electronics industry to pattern line channels on silicon chips, ceramic substrates, and circuit boards. The photolytic process often requires an ultraviolet light exposure and subsequent bake to produce the required properties, prior to solvent development operations. An in situ FT-IR method was developed to assess the cross-linking reaction induced by UV exposure and investigate the effect of temperature on the overall reaction. The method employs a commercially available heated sample cell holder and an in-house fabricated fiber optic exposure tool. The UV-induced cure reaction was monitored as a function of time. The effect of bake temperature after exposure was also monitored.