Electromigration is a wearout mechanism that contributes significantly to IC failures. This article discusses the causes and effects of this often overlooked failure mode and presents practical guidelines to help analysts determine whether or not electromigration is the cause of a particular failure. It also discusses the differences between aluminum and copper electromigration.

With the introduction of 65 nm technology, the cross-sectional dimensions of copper interconnect in some layers are now smaller than 100 nm, which translates to current densities on the order of several MA/cm2. Electromigration as a root cause for chip failure is thus a major concern and is still being examined. In this article, the authors present recent failure analysis studies on metal-coated copper interconnects, using OBIRCH techniques in combination with FIB cross-sectioning and SEM and TEM imaging.