Selective etch for silicon films

A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed nitrogen-and-silicon-containing region and an exposed silicon-containing region which contains less nitrogen than the nitrogen-and-silicon-containing region, the method comprising:

• flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to but physically separated from the substrate processing region while forming a plasma in the first plasma region to produce plasma effluents;
• neutralizing charged species generated in the remote plasma prior to flowing plasma effluents into the substrate processing region by flowing the plasma effluents through an ion suppressor plate positioned within the substrate processing chamber, wherein the plasma effluents exiting the ion suppressor plate comprise less than 10 percent charged species;
• etching the exposed silicon-containing region faster than the exposed nitrogen-and-silicon-containing region by flowing the plasma effluents into the substrate processing region;
• and
• wherein the exposed silicon-containing region consists essentially of silicon and the etching is generally uniform.