Patent ID: 7294579

Claim:
A method for forming a contact opening, comprising the steps of: providing a substrate, wherein the substrate has a conductive pattern and at least a dielectric layer covering the conductive pattern formed thereon, and the conductive pattern comprises a metallic layer and an anti-oxidation conductive layer over the metallic layer; forming a photoresist layer over the dielectric layer, wherein the photoresist layer has a first opening; performing a plasma etching process to form a second opening in the dielectric layer using the photoresist layer as a mask, wherein the first opening is located above the second opening, and a bottom part of the first opening has a diameter smaller than that of a top part of the second opening, and the anti-oxidation conductive layer exposed by the first opening is removed in the plasma etching process; and removing the photoresist layer, wherein the anti-oxidation conductive layer in the second opening surrounds the metallic layer from the top view.