Plasma etching is an integral part of semiconductor integrated circuit (IC) processing and is widely used for a variety of applications such as high-resolution pattern definition, selective processing over topography, planarization, and sacrificial layers stripping. A plasma process that is used to transfer lithographically defined patterns into thin layers must satisfy constraints that include dimensional control, etch selectivity to mask, and the nature of the underlying surface or layer [1,2]. The behaviors of most inorganic materials used in semiconductor processing, such as silicon,polysilicon, silicon nitride, and silicon dioxide, have been well characterized. Their etching directionality and etching selectivity can be controlled by etch gas composition and other plasma conditions