In accordance with this disclosure, there is provided several inventions, including a method for etching a plurality of features in a stack comprising alternating layers above a substrate, comprising: providing a steady state flow of an etching gas, wherein the etching gas comprises: a molecule A comprising sulfur and fluorine; a molecule B comprising carbon, fluorine, and hydrogen; and a molecule C comprising carbon and fluorine and not hydrogen; forming the etching gas into a plasma; and etching the features into the stack through the plurality of alternating layers.