Photosensitive Polyimide for Panel-Level RDL Insulator

Processing a re-distribution layer (RDL) in a large panel, explosion-proofing processes are necessary for safety. For this reason, photosensitive insulating materials that can be developed with alkaline water and nonexplosive patterning processes are required. In addition, when using large panel, warpage due to thermal stress can also be an issue. We have developed relatively low stress fine pattern capable positive photosensitive type materials that can be developed with alkaline water, and negative photosensitive type materials that have low stress and are capable of high aspect ratio pattern processing. Furthermore, these materials have sufficient insulating reliability, and the negative-type materials can also be made into B-stage sheets. We report on these properties.