Influences of Ta passivation layers on the fatigue behavior of thin Cu films

Fatigue behavior of 100 nm and 1.0 µm thick Cu films with 10 nm Ta passivation layers has been studied using cyclic tensile testing. The results show that Ta capping-layer has influences on fatigue damage by suppression of extrusion formation and, thereby, improved the fatigue life dramatically in the 1.0 µm thick Cu film, but does not change the fatigue life of 100 nm thick Cu film for which crack formation is the dominant damage mechanism.