Studies on Failure Mechanism of Al Fluoride Oxide-AlxOyFz on Microchip Al Bondpads

Al fluoride oxide on microchip Al bondpads may cause non-stick on pad (NSOP) problem during bonding process. In this study, a failure mechanism to form Al fluoride oxide-Al_xO_yF_z has been proposed. Based on the failure mechanism, F contamination on Al bondpads, it will chemically react with Al and 3 form Al-F complex compound, such as [AlF₆]^3-. [AlF₆]^3- formed may become an anode and further chemical reaction from O₂ and moisture (H₂O) will occur at the cathode and form the new product, OH-ions, which will undergo chemical reaction with Al to form Al(OH)₃, and then become Al₂O₃. Finally, Al-F complex compound may further chemically react with Al₂O₃ to form Al fluoride oxide- Al_xO_yF_z.