Abstract: Exemplary methods of etching a silicon-containing material may include flowing a fluorine-containing precursor into a remote plasma region of a semiconductor processing chamber. The fluorine-containing precursor may be characterized by a molecular formula of XFy, and y may be greater than or equal to 5. The methods may include forming a plasma within the remote plasma region to generate plasma effluents of the fluorine-containing precursor. The methods may include flowing the plasma effluents into a processing region of the semiconductor processing chamber. A substrate may be positioned within the processing region, and the substrate may include a trench formed through stacked layers including alternating layers of silicon nitride and silicon oxide. The methods may include laterally etching the layers of silicon nitride.