Method of forming a local interconnect with improved etch selectivity of silicon dioxide/silicide

摘要

A method and arrangement for forming a local interconnect without weakening the field edge or disconnecting the diffusion region at the field edge introduces additional nitrogen from a nitrogen plasma into a nitrogen-containing etch stop layer (e.g., SiON) that has already been deposited by plasma enhanced chemical vapor deposition (PECVD), for example. The enriched nitrogen etch stop layer is harder to etch than conventional PECVD SiON so that when etching the dielectric layer in which the local interconnect material is to be subsequently deposited, the etching stops at the etch stop layer in a controlled manner. This prevents the unintentional etching of the silicide region and diffusion region at the field edge.