Photochemical generation of polysiloxane surfaces on polymers, and subsequent oxygen plasma resistance

Abstract

Polymers that can form sulfonic acid units in their side-chains upon irradiation with UV light have been synthesized by the copolymerization of 1,2,3,4-tetrahydro-l-naphthylideneamino styrene-p-sulfonate (NISS) with either methyl methacrylate, isopropyl methacrylate, or benzyl methacrylate. When the irradiated polymers having NISS units were exposed to methyltriethoxysilane (MTEOS) vapour at 30°C, polysiloxane networks were formed at the near surface of the polymers. No polysiloxane networks were formed at the unirradiated areas. The rate of polysiloxane formation increased with NISS fraction in polymers and decreased with increasing hydrophobic nature of the methacrylate units. The polymers, which were irradiated and subsequently exposed to MTEOS vapour showed good etch resistance to an oxygen plasma.