The primary purpose of the SWS Nitride Anisotropic Back Etch is to form the critical sidewall spacers by removing the conformal silicon nitride layer from horizontal surfaces while selectively preserving it on the vertical gate sidewalls A1.In the process flow, this step immediately follows the deposition of a thin pad oxide and the bulk SWS nitride, and it prepares the device for the subsequent highly-doped Source/Drain (S/D) ion implantations P3.By dictating the exact physical separation betwe