Corrosion of anodized aluminum alloys in plasma halide chemistry

One of the harshest environments that anodized aluminum alloys experience is in the plasma CVD (Chemical Vapor Deposition) reactors that are used in semiconductor manufacturing equipment. A study was undertaken to understand the properties and behavior of anodized aluminum alloys used in plasma CVD chambers. Special attention was given to the interaction of the anodized Al electrode and the film properties on the wafers that sit on the anodized Al electrode during CVD film deposition. During the course of the investigation numerous anodized aluminum alloy parts were analyzed to determine the root cause of failure. The root cause was determined to be the degradation of the anodized layer resulting from fluorination of the aluminum substrate. The degradation is dependent upon the manufacturing parameters involved in the anodization process and the alloy composition. This investigation revealed the beneficial effects of Mg in the aluminum alloy and led to the development of the E 80{dollar}sp{lcub}rm TM{rcub}{dollar} alloy. Anodized E 80 alloy proved to have superior corrosion resistance compared to anodized 6061 and 1100 Al alloys in plasma halogenated environment.