Porous and Directly Patternable PTFE Films Grown By Hot-Filament Chemical Vapour Deposition

摘要

Hot filament chemical vapor deposition (HFCVD) from hexafluoropropylene oxide (HFPO) yields films having the linear -CF_2- chain structure of poly(tetrafluoroethylene) (PTFE). The surface morphology of the HFCVD films depends strongly on processing conditions. The roughest films display a microstructure having anisotropic nodules which interconnect to form a porous superstructure. Smoother HFCVD fluorocarbon films are of interest for a direct patterning lithographic process: HFCVD films were selectively electron beam irradiated and developed using supercritical CO_2. The result was positive-tone contrast and fully-developed images at 0.25-micron resolution.