Study of void formation in Cu interconnects using local sense and standard singlevia structure

In this paper the void formation during electromigration is characterized with the innovative Local Sense Structure (LSS) and with a standard single-via (SSV) electromigration test. LSS allows the measurement of small resistance change before final void formation, that have allowed to define a time of nucleation of the void (Tn). Furthermore, the classic structure has been used to evaluate the time to failure and to study in detail the “plateau” of void formation, where we suppose the void nucleates. The comprehension of nucleation and others phenomena before the classic jump of resistance will be fundamental for the future of interconnects reliability physics and lifetime prediction.