Methods and systems to mitigate etch stop clipping for shallow trench isolation fabrication

Abstract

The present invention facilitates semiconductor fabrication by maintaining shape and density of an etch stop layer () during trench fill operations. The shape and density of the etch stop layer () is maintained by forming a protective alloy liner layer () on the etch stop layer () prior to trench fill operations. The protective alloy liner () is comprised of an alloy that is resistant to materials employed in the trench fill operations. As a result, clipping and/or damage to the etch stop layer () is mitigated thereby facilitating a subsequent planarization process that employs the etch stop layer (). Additionally, selection of thickness and composition () of the formed protective alloy () yields a stress amount and type () that is applied to channel regions of unformed transistor devices, ultimately providing for an improvement in channel mobility.