Stepped current stressing of line/stud structures

Abstract

We have used stepped-current stressing to look at the stability of refractory liners used in Al-based interconnects. These redundancy layers play a critical role in the reliability of Al-based interconnects by allowing current flow even when the Al portion of the line is damaged by electromigration or stress migration. For this work, we have used line/stud structures, both as-received and previously damaged, and analyzed results with respect to a simple model that describes temperature increase in terms of material properties and thermal conduction. We discuss the difference in behavior of damaged and undamaged lines, the temperature associated with failure, and the implications for current-limit design rules.