SELECTIVE PLASMA ETCHING OF SILICON NITRIDE IN PRESENCE OF SILICON OR SILICON OXIDES USING MIXTURE OF (NH3 OR SF6) AND HBr AND N¿2?

摘要

An RIE method and apparatus provides uniform and selective etching through silicon nitride material of a supplied workpiece such as a silicon wafer having silicon oxide adjacent to the SiN. A plasma-maintaining gas that includes N2 having an inflow rate of at least 10 sccm is used to provide etch-depth uniformity across the workpiece. The plasma-maintaining gas further includes HBr and one or both of NF3 and SF6.