Self-biasing effects on plasma etching characteristics of Si and SiO2

The effects of ion energy on the etching characteristics of Si and SiO2 are studied in a SF6 multipolar microwave plasma in the 0–400 eV range. For constant plasma conditions, the ion energy is varied by using independent rf wafer biasing. The variations observed in the anisotropy and etch rates of Si and SiO2 are discussed in the light of previous experimental results and in terms of the current models for plasma etching.