Influence of crystal orientation on the oxidation failure of copper for IC package

The effect of crystal orientation on the oxidation failure of pure copper was investigated. XRD results indicated that the oxide film grown on copper surface was mainly composed of Cu₂O. The adhesion strength between Cu(110) and its oxidization film was the highest, whereas, the adhesion strength between Cu (311) and its oxidization film was the lowest. SEM observations revealed that the oxide film grown on Cu (311) delaminated from substrate, while the oxide film grown on Cu (100) and Cu (110) did not reveal such a phenomenon. The oxidation rate was investigated by measuring oxide film thickness using the cathodic reduction method. The thickness of oxide film grown on Cu (100) and Cu (110) was thinner than those on Cu (311) and Cu (111). The activation energy for film growth on Cu (100) was calculated to be the highest while that on Cu (311) was the lowest.