Angle-resolved XPS investigation of the fluorine-related passivation layeron etched Al (Cu 1%) surface after SF6 treatment

A fluorine-related passivation layer on etched Al-Cu alloy films was invest igated by transmission electron microscope (TEM) and angle-resolved X-ray p hotoelectron spectroscopy (XPS). The passivation layer was produced during SF6 plasma treatments after SiCl4/Cl-2/He/CHF3 mixed gas plasma etching. Th e passivation layer is composed of fluorine-aluminum compounds on the etche d Al-Cu surface. It was found that this lay er suppresses effectively the c orrosion on the etched surface by preventing moisture penetration from air even if the residual chlorine atoms exist on the etched surface. The existe nce of the passivation layer was verified by TEM analysis. To investigate c haracteristics of the passivation layer, angle-resolved XPS was carried out for heat-treated samples. The heat treatments of the samples were in-situ carried out in the XPS analysis chamber for the temperatures of 150, 300, a nd 400 degrees C, respectively. The binding energy of the composed elements of the passivation layer shifted to the higher binding energy position as the heat treatment temperature was increased.