Exemplary semiconductor processing methods may include providing an oxygen-containing precursor to a processing region of a semiconductor processing chamber. The methods may include forming a plasma of the oxygen-containing precursor to produce oxygen-containing plasma effluents. The methods may include contacting a substrate housed in the processing region with the oxygen-containing plasma effluents. The substrate may include a boron-and-nitrogen-containing material overlying a carbon-containing material. The boron-and-nitrogen-containing material comprises a plurality of openings. The methods may include etching the carbon-containing material.