Study of thin gate of oxide etching during plasma patterning of 0.1 mu m Si gates

When optimizing a 0.1 mu m gate etching process using a standard chemistry and plasma operating conditions, we have observed an unsuspected behavior o f thin gate oxides. By combining X-ray Photoelectron Spectroscopy (XPS) and spectroscopic ellipsometry, we have attributed this behavior to reactive s pecies penetration through the thin gate oxides. This phenomenon could play an important role in the sub-0.1 mu m CMOS process optimization.