Study on the high via resistance by TEM failure analysis

In this work we reported a case study onET(electrical testing) failure with via high resistance issue. In order to understand the failure mechanism and rootcause behind the high via resistance, detailed TEM(transmission electron microscope) analysis wasperformed by using various TEM FA (failure analysis)techniques, including EDX, EELS analysis. It was foundout that high via resistance arose from the process driftinduced Al extrusion and poor barrier metal coverage atvia bottom. The correlation between the physicalsignatures identified by TEM FA and the associatedprocesses were discussed for the root cause understanding.