The effect of current density and stripe length on resistance saturation during electromigration testing

Resistance saturation as a function of current density and stripe length has been investigated for a two-level structure with Ti/TiN/AlCu/Ti/TiN stripes and interlevel W stud vias. A simple model relating the resistance change at saturation to the current density and stripe length is formulated for structures with short stripe lengths and blocking boundaries at both ends. Experimental results for stripe lengths of 25, 50, or 100 μm are in good agreement with the model predictions.