Enhancement of electromigration lifetime of aluminum interconnection line by stress accommodation of interfaced oxide

In this work, we have applied an overlying and underlying oxide layer interfaced with metal interconnection line for stress accommodation, which can lead to retardation of Al atom divergence. It is understood that the major reason for the improvement of electromigration lifetime is due to the tensile stress of overlying oxide acted as a counteractive force on the intrinsic tensile stress of Al interconnection line. In case of underlying oxide, the lower surface tension of oxide improves the wetting of metal deposits and it allows the metal grains to grow into larger sizes revealed by a focused ion beam (FIB) image.