Patent ID: 6472329
Filing Date: 2002-10-29
Classification: C23F,H01L

Abstract:
A method of etching an exposed region of a multi-layer metal on a semiconductor workpiece, wherein the metal includes at least a first layer of refractory metal underlying a second layer of aluminum or aluminum alloy, comprising the steps of:providing a semiconductor workpiece that includes an exposed region of a multi-layer metal that includes at least a first layer composed of a first refractory metal underlying a second layer composed of aluminum or aluminum alloy, and other material underlying the multi-layer metal on the workpiece; exposing the workpiece to a first atmosphere that etches aluminum, wherein the first atmosphere is produced by plasma decomposition of a first gas mixture; and subsequently exposing the workpiece to a second atmosphere that etches the first refractory metal faster than it etches aluminum, wherein the second atmosphere is produced by plasma decomposition of a second gas mixture; wherein the first gas mixture includes a fluorocarbon compound; and wherein the second gas mixture includes an oxygen-containing species.