Abstract: A method of etching silicon nitride spacers beside a gate structure comprising: providing a gate electrode over a gate oxide layer on a substrate. A liner oxide layer is provided over the substrate and the gate electrode. A silicon nitride layer is provided over the liner oxide layer. The invention's nitride etch recipe is performed in a plasma etcher to anisotropically etch the silicon nitride layer to create spacers. The nitride etch recipe comprises a main etch step and an over etch step. The main etch step comprises the following conditions: a Cl2 flow between 35 and 55 molar %, a He flow between 35 and 55 molar %, a backside He pressure between 4 and 10 torr; and a HBr flow between 7.5 and 12.5 molar %; a pressure between 400 to 900 mTorr; at a power between 300 and 600 Watts. The etch recipe provides a spacer width to nitride layer thickness ratio of about 1:1 and does not pit the Si substrate surface.

Abstract: A new method of forming silicon nitride sidewall spacers has been achieved. This method is used to fabricate tapered, L-shaped spacer profiles using a two-step etching process that can be performed insitu. In accordance with the objects of this invention, a new method of forming silicon nitride sidewall spacers has been achieved. An isolation region is provided overlying a semiconductor substrate. Conductive traces are provided overlying the insulator layer. A liner oxide layer is deposited overlying the conductive traces and the insulator layer. A silicon nitride layer is deposited overlying the liner oxide layer. The silicon nitride layer is anisotropically etched down to reduce the vertical thickness of the silicon nitride layer while not exposing the underlying liner oxide layer. The silicon nitride layer is etched through to form silicon nitride sidewall spacers adjacent to the conductive traces.