FA cannot consist of simply jumping to conclusions. The FA process is validated through correlation with the initial failure and through interpretation of the obtained results, subjective by definition. This paper illustrates the difficulty of analyzing complex failures caused by multiple factors, including wafer fabrication, assembly, and application conditions. Inter-Layer Dielectric (ILD) delamination was experienced on various ICs from the same 250nm technology. A complete set of techniques (C-SAM, laser and optical microscopy, SEM, FIB cross-sections, TEM, EFTEM, SIMS, Auger, delineation) was used as different pieces of the same puzzle to reveal the multiple factors contributing to the ILD delamination failures. Due to the subtle nature of some of the underlying causes, defining an accurate FA approach with appropriate sample preparation and accurate device traceability was critical to understanding this complex, multivariate issue.

Wire bonding is the most highly used interconnection technology in the packaging of integrated circuits. One of the potential risks of wire bonding is the damage on the oxide layers underneath the bond pad. Oxide damage monitoring is necessary to ensure bonding has no impact on the oxide layers under the bond pad. Since the oxide layer is not seen by visual inspection, bond pad stripping is necessary. Three bond pad stripping chemicals KOH, Aqua regia, and phosphoric acid were investigated in this study. Results obtained by dipping the chemicals at different temperatures, and time scales will be given. An optical microscope (OM) and scanning electron microscope (SEM) are used to observe the oxide conditions from the top view. To understand the mechanism of the oxide damage caused by wire bonding, a focused ion beam was used to observe the cross-section of the defect.