Effect of Ultraviolet Radiation from an Oxygen Plasma on the Atomic Oxygen-induced Etching of Fluorinated Polymer

The contribution of extreme ultraviolet (EUV) and vacuum ultraviolet (VUV) from a laser-sustained plasma on mass loss phenomenon of fluorinated polymer in the ground-based laser-detonation atomic oxygen (AO) beam source was evaluated. The AO beam and EUV/VUV from an oxygen plasma were separated by a high-speed chopper wheel installed in the beam source. Mass changes of fluorinated polymer and polyimide were measured from the frequency shift of the quartz crystal microbalances during the beam exposures. It has been made clear that the fluorinated polymer is eroded by EUV/VUV exposure alone. In contrast, no erosion was detected for polyimide by EUV/VUV alone. The AO-induced erosion was measured for both materials even without EUV/VUV exposure. However, no strong synergistic effect was observed for the fluorinated polymer even under the simultaneous exposure condition of AO and EUV/VUV. Similar results were observed even in the simultaneous exposure condition of AO (without EUV/VUV from the laser plasma) and VUV from the 172 nm excimer lamp and D(2) lamp. These experimental results suggest that the primary origin of the accelerated erosion of fluorinated polymer observed in the laser detonation AO source is not EUV/VUV from the laser-sustained plasma.