Notch profile defect in aluminum alloy etching using high-density plasma

An etching profile distortion called a 'notch' was observed in Al alloy etching using inductively coupled plasma and electron cyclotron resonance plasma etcher. Mechanisms of notch formation and reduction were discussed. Electron charge up and the lowered electrical potential of the specific patterns are the reasons for the notch occurrence. Notches are smaller at the Al/Ti(O)N stacked structure. A new etching method is proposed for eliminating notches and achieving high selectivity employing an ICP etcher.