Method of forming a shallow trench isolation structure

摘要

A method for reducing preferential chemical mechanical polishing (CMP) of a silicon oxide filled shallow trench isolation (STI) feature during an STI formation process including providing a semiconductor wafer having a process surface including active areas for forming semiconductor devices thereon; forming a silicon oxynitride layer over the process surface for photolithographically patterning STI trenches around the active areas; photolithographically patterning STI trenches around the active areas for anisotropic etching; anisotropically etching the STI trenches extending through the silicon oxynitride layer into the semiconductor wafer; depositing a silicon oxide layer over the silicon oxynitride layer to include filling the STI trenches; and, performing a CMP process to remove the silicon oxide layer overlying the silicon oxynitride layer to reveal an upper surface of the silicon oxynitride layer.