Photopatternable thin films from silyl hydride containing silicone resins and photobase generators

The photopatternability of various silyl hydride containing organosilicone resins containing the photobase generators N-methylnifedipine or O-(2-nitrobenzyl)-N-octyl carbamate have been examined, with the goal of identifying potential photopatternable compositions with high thermal stability after cure. Two different categories of silicone resins have been prepared from combinations of diphenylsiloxane and methyl and hydrogen silsesquioxane units and a combination of phenyl and hydrogen silsesquioxane monomer units. The photobase generators were incorporated into these resins at concentrations up to 10 weight percent. UV-irradiation of micrometer thick silicone resin-photobase films through a photomask, under an air atmosphere, yielded micrometer scale features after development. Photopatternable compositions have been identified with photosensitivities of less than 50 mJ/cm2. The photopatterning process is believed to proceed by base-catalyzed reaction of resin-based silanol groups with neighboring silyl hydride groups to yield thermally stable siloxane crosslinks.