Notch stop pulsing process for plasma processing system

摘要

A method for etching a substrate having a silicon layer in a plasma processing chamber having a bottom electrode on which the substrate is disposed on during etching. The method includes performing a main etch step. The method also includes terminating main etch step when a predefined etch depth of at least 70 percent of thickness into silicon layer is achieved. The method further includes performing an overetch step. The overetch step including a first process step and a second process step. First process step is performed using a first bottom power level applied to bottom electrode. Second process step is performed using a second bottom power level applied to bottom electrode that is lower than first bottom power level. First process and second process steps are alternately performed a plurality of times. The method yet also includes terminating overetch step after silicon layer is etched through.