400 kHz Radio-Frequency Biased Electron Cyclotron Resonance Position Etching

Abstract
A radio frequency (RF) biased electron cyclotron resonance plasma etching technology has been developed to realize efficient ion acceleration in high-density, uniform ECR plasma. 400 kHz RF-biased ECR position etching can achieve uniform and efficient ion acceleration, and prevents charge build-up damage to the thin gate oxide. Conversely, at frequency of more than 700 kHz, the plasma is disturbed by the local discharge between the grounded chamber wall and the substrate holder. Then, the gate oxide breakdown is caused by the stored charge due to the potential difference on the substrate.