Preparation of positive photoreactive polyimides and their characterization

Abstract

Polyimide precursors were synthesized from a diamine and a diacid chloride that was derived from the reactant with promellitic dianhydride and o-nitrobenzyl alcohol. Their thermal properties were studied in nitrogen using dynamic thermogravimetry, and the photoreaction mechanism was investigated by ultraviolet and infrared spectrophotometry. The polyimide precursors were spin-coated onto silicon wafers, prebaked, and then exposed to UV light from a high pressure Hg–Xe lamp. When the films were dipped into 2% aqueous KOH after irradiation, the exposed area dissolved forming high resolution patterns. Relative sensitivities of the polymers were determined.