Effects of H₂ addition in magnetized inductively coupled C₂F₆ plasma etching of silica aerogel film

Effect of H₂ addition to C₂F₆ plasma etching of SiO₂ aerogel film was examined for low-k dielectric application. In this experiment, H₂ plasma in itself was responsible for pore blocking and bond breaking of the SiO₂ aerogel. With increasing hydrogen from 0 to 50%, etch rate of SiO₂ aerogel was severely dropped at 20% of H₂ addition. According to the increase in H₂ addition, transition from fluorine-rich residue to carbon-rich one was gradually happened in SiO₂ aerogel. Surface microstructure of SiO₂ aerogel was so influenced with the increasing H₂ addition that they transformed to be planar by the interaction between residue/network and ion bombardment and the condensation reaction of surface chemicals with H₂ plasma.