Base-amplifying silicone resins with photobase-generating side chains and their application to negative-working photoresists

To accomplish high photosensitivity of resist systems including photobase generators, we have proposed the concept of base-proliferation reactions that generate base molecules in a nonlinear manner by the action of a catalytic amount of base; however, excessive diffusion of generated base molecules is still a problem. We have designed novel functional silicone resins bearing both base-amplifying units and photobase-generating units, and synthesized resins with various composition ratios. The synthesized resins are decomposed autocatalytically after UV irradiation and subsequent heating at 100 °C, which indicates progression of base-proliferation reactions. High photosensitivity (8.1 mJ cm−2) was recorded, and it was found that the photosensitivity is about 490 times enhanced by replacing a base-catalytic reaction system with the base-proliferation reaction system. Furthermore, a 4 × 10 µm line-and-space pattern has been successfully fabricated using the silicone resin.