Patent attributes
A method for fabricating a semiconductor device is provided including providing a substrate, on which a plurality of elements is formed. A first inter-dielectric layer is formed over the substrate, covering the elements. A first plug structure is formed in the first inter-dielectric layer, including performing a polishing process over the first inter-dielectric layer to have a dishing on top and extending from a sidewall of the first plug structure. A hard mask layer is formed to fill the dishing. A second inter-dielectric layer is formed over the hard mask layer. A second plug structure is formed in the second inter-dielectric layer to electrically contact the first plug structure, wherein the second plug structure has at least an edge portion extending on the hard mask layer.