Observation of Electromigration Voiding in Cu Lines

Abstract

ABSTRACTCu film characteristics and in-situ observation of electromigration voiding in passivated Cu lines are reported. Measured grain size distribution show a median grain size of 0.4 μm. A 3 μm wide, 800 μm long line passivated with 5000 Å of SiO2 was tested in a high voltage scanning electron microscopy (HVSEM), enabling dynamic in-situ events to be recorded. Electromigration voiding in this line showed some similarity to that previously observed in polygranular Al lines. Transmission electron microscopy was used to study the microstructure of the passivated Cu lines.