サブミクロン銅薄膜の疲労き裂進展に及ぼす表面酸化層の影響

抄録

To investigate the effects of surface oxide layer on fatigue crack propagation properties of submicrometer-thick metallic films, in situ field emission scanning electron microscope observations of fatigue crack propagation were conducted in approximately 500-nm-thick freestanding copper (Cu) films with roughly 1-nm-thick native oxide layer and with roughly 10-nm-thick thermal oxide layer. The fatigue crack in the films with native oxide layer propagated with intrusions/extrusions formation ahead of the fatigue crack tip, and then the fatigue crack stably propagated through the intrusions/extrusions. In contrast, obvious intrusions/extrusions were not formed and rapid fatigue crack propagation occurred in the films with thermal oxide layer. Fatigue crack propagation rate da/dN of the films with thermal oxide layer was higher than that of the films with native oxide layer.