Plasma Etching of Silicon Oxynitride in a Low-Pressure C2F6 Plasma
Silicon oxynitride films were etched at a low pressure of 6 mTorr in a C{sub 2}F{sub 6} inductively coupled plasma. The examined etching characteristics included the etch rate, the profile angle, the surface roughness, and microtrenching. For comparison, etch data were collected at a high pressure of 12 mTorr. Irrespective of the pressure level, etch rate variations with either the source power or the bias power were identical. Larger etch rates and smaller surface roughnesses were observed at lower pressures. Increasing the bias power or the source power was beneficial for obtaining a smaller surface roughness. A profile angle variation just over microtrenching was effective in interpreting microtrenching variations.