Highly reliable low temperature curable photosensitive polyimide

Low temperature curable photosensitive polyimide having extremely good Cu migration resistance were developed by examining the polyimide structure, photo chemistry, cross-linkers. We observed the polyimide structure affected the Cu migration resistance mainly. Polyimide having soft segment shows better Cu migration resistance. Addition of photosensitivity (positive tone and negative tone) was not affect so much. Those observation results were more than that we expected. Soft segment unit may add better flowability to cover Cu wiring without any damage to show better Cu migration resistance. In addition, void formation was observed between Cu and polyimide layer. The void was formed due to Cu oxide diffusion at high temperature storage. To suppress the void generation, we found some anti-oxidation method is effective. In order to obtain fine pattern formation as well as high Cu migration, we developed positive tone photosensitive polyimide coating and B-stage sheet using soft segment in the polyimide with thermal cross linker.