Photosensitive Polyimide-silicone Copolymer based on Reaction Development Patterning (RDP)

RDP using mixtures of TMAH / water / NMP / methanol as developers was applied to the commercially available polyimide-silicone copolymer, and when the amount of NMP in the developer was small, pattern having sufficient concavo- convex shape was not obtained. On the other hand, the use of the developer containing a large amount of NMP resulted in the formation of clear negative-tone patterns. The pattern-forming mechanism is considered to be the same as that proposed for negative-tone pattern formation of polyetherimide by RDP, that is, retardation of the reaction between imide groups in the polymer and OH- in the developer induced by the photo-generated insoluble PMI dimer and the reaction between OH- and the photo-generated acid from DNQ.