Patent ID: 6593223
Filing Date: 2003-07-15
Classification: H01L

Abstract:
A method for forming a dual damascene structure, the method comprising the steps of:providing a substrate having a conductive region formed thereon; forming a first dielectric layer, an etch-stop layer and a second dielectric layer over the substrate, wherein the etch-stop layer comprises silicon oxynitride; selectively etching the second dielectric layer, the etch-stop layer and the first dielectric layer until a portion of the conductive region is exposed to form a first opening; third etching the second dielectric layer to form a second opening and a third opening over the first opening until a portion of the etch-stop layer is exposed within the second opening, wherein the first opening is further enlarged by said third opening so that the first and the third openings together form a dual damascene structure, wherein an etching rate of the second dielectric layer is substantially different than an etching rate of the etch-stop layer to assist in the formation of the first and second openings; and forming a second conductive layer inside the first opening and the second opening of the dual damascene structure.