Effect of Electric Field on Electron Cyclotron Resonance Plasma Etching

Recent studies of etching technology using plasma indicate that serious problems are induced by a charge build-up. The charge build-up causes radiation damage and distortion of etched profiles. These problems are induced by a non-neutrality of charge supply to the surface. By controlling the electric potential of surface material with a dc power supply, dependences of damage and pattern distortions on charge-up are investigated. Keeping the net current to the wafer zero is effective for reducing the radiation damage. The profile distortions occur due to the potential difference between mask and etched material. The profile is improved by setting the applied dc potential equal to floating potential.