A etch stop layer for use in a silicon oxide dry fluorine etch process is made of silicon nitride with hydrogen incorporated in it either in the form of N—H bonds, Si—H bonds, or entrapped free hydrogen. The etch stop layer is made by either increasing the NH3 flow, decreasing the SiH4 flow, decreasing the nitrogen flow, or all three, in a standard PECVD silicon nitride fabrication process. The etch stop can alternatively be made by pulsing the RF field in either a PECVD process or an LPCVD process.