SYNTHESES AND CHARACTERIZATION OF PHOTOCROSSLINKABLE POLY(AMIC-ACID-CO-UREA)S WITH DIAZORESIN

To improve the transparency, flexibility, and solubility of polyimide, and to fabricate a negative working photoresist, polyamic acid, polyu rea, and poly(amic acid-co-urea) in various contents were synthesized. Photosensitive diazoresin was synthesized and was used as the photocr osslinking agent. Characteristics of the polymers were identified by u sing IR, EA, DSC, TGA, and UV. From dissolution capabilities and therm al properties of the polymers, we chose the most suitable polymer PA25 as the main resin of the negative photoresist. The mixture of the pol ymer and diazo resin can be used as a negative photoresist. Optical ch aracteristics of the polymer and diazo resin were evaluated by UV spec trophotometer. It was found that the polymer and diazo resin showed di fferent absorption wavelengths under UV exposure. Characteristics of t he negative photoresist were investigated by using i-line lithography. A contact printing exposure technique was used in this investigation. Dissolution rate and resolution capability of the photoresist contain ing various amounts of diazo resin were evaluated. The optimal prebaki ng time, postbaking time, and SEM patterns of the negative photoresist were also investigated. (C) 1998 John Wiley & Sons, Inc.