Characterization of Binding Energy of Al Hexafluoride [AlF6]3- in X-Ray Photoelectron Spectroscopy

X-ray photoelectron spectroscopy/electron spectroscopy for chemical analysis (XPS/ESCA) is being widely used in failure analysis of semiconductor industries and wafer fabrication, as it is able to provide not only elemental information, but also chemical binding information. For example, using its fingerprint of C=O, we are able to identify possible root causes of carbon contamination in wafer fabrication (fab). In wafer fab, it is also being successfully used in failure analysis for Al fluorides on microchip Al bondpads. It is well known fact that it is difficult or impossible for us to fully free fluorine (F) from Al bondpads if F-based chemical gases such as CF₄ and CHF₃ are used for Al bondpad opening process in wafer fab. However, it is possible to reduce and control the F contamination to within the background/baseline level, which will not affect the bonding process at assembly houses