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.