Critical Role of Intermetallic Particles in the Corrosion of 6061 Aluminum Alloy and Anodized Aluminum Used in Semiconductor Processing Equipment

The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology characterization. The results revealed that a huge difference of corrosion resistance between imported and domestic 6061 aluminum alloys in HCl solution and gas acid mist experiments mainly was attributed to the different size and amount of Al₁₅(Fe,Mn)₃Si₂. The corrosion resistance of domestic 6061 alloy in dry/wet semiconductor electronic special gas environments was worse than that of imported aluminum alloy, and there are great differences in the corrosion mechanism of 6061 alloy caused by the second phase in the two dry/wet environments. And the corrosion resistance of the hard anodized alumina film was closely related to the microscopic morphology of holes. The vertical and elongated α-Al₁₅(Mn,Fe)₃Si₂ phase was formed in the rolled aluminum alloy that has been rolled perpendicular to the surface of the substrate. Compared to the horizontal long hole, the longitudinal long holes generated by the vertical α-Al₁₅(Mn,Fe)₃Si₂ phase will enable the corrosive medium to reach the substrate rapidly, which significantly weakens the corrosion resistance of the hard anodized film.