Microstructure and Scratching Characterization of Cu Deposited Film after Annealing Treatment

Copper films with thickness 5 μm were deposited by electron beam evaporation on slightly oxidized silicon substrates. Ti and Al metals were used as adhesion or barrier layers. XRD was used to detect the microstructure related to the resistivity after annealing in N2 gas. The scratch characterization of Cu films was also investigated using a scratch indenter of radius of 2.5 μm. Results revealed that the resistivity decreases, but scratch resistance increases after annealing. The contact stiffness (dP/dh) of as-deposited film was estimated to be 170 ×103 N/m. The loading curve of annealing samples could be described using a linear relationship between the load P and the square of the depth (P=Ch2, C=17.5 GPa).