US Patent 9735015 Fabricating method of semiconductor structure

A method of manufacturing a semiconductor structure, comprising: providing a preliminary structure having a first region and a second region and comprising a plurality of first trenches in the first region; forming a metal layer filling the first trenches covering on the preliminary structure, wherein the metal layer comprises a concave portion in the second region and the concave portion defines an opening; forming a metal nitride layer on the metal layer by an nitride treatment; and performing a planarization process to remove the metal nitride layer and a portion of the metal layer to expose the preliminary structure.