Highly selective nitride etching employing surface mediated uniform reactive layer films

摘要

Disclosed is a method of selectively etching nitride in a chemical downstream etching process. The invention begins by placing a wafer having oxide regions and nitride regions in a chamber. Then, the invention performs a chemical downstream etching process using CH₂F₂ to etch and convert the nitride regions into surface mediated uniform reactive film (SMURF) regions comprising (NH₄)₂SiF₆. This process then rinses the surface of the wafer with water to remove the surface mediated uniform reactive film regions from the wafer, leaving the oxide regions substantially unaffected. The chemical downstream etching process is considered selective because it etches the nitride regions at a higher rate than the oxide regions.