Method of forming wiring structure of semiconductor device

摘要

A wiring structure of a semiconductor device includes a substrate; a first conductive layer formed in the substrate; an insulation film formed on the substrate including the first conductive layer and having a contact hole therein through which the upper surface of the first conductive layer is exposed, wherein the contact hole includes an upper contact hole and a lower contact hole having a shape undercut into the insulation film and thus being wider than the upper contact hole; and a second conductive layer formed on the insulation film so as to thoroughly fill the contact hole and electrically connected to the first conductive layer.