Copper stress migration at narrow metal finger with wide lead

Copper stress migration (SM) at narrow metal finger connected with wide lead is investigated in this work. Voiding phenomenon is explored with respect to specific failure site. Metal geometric factors including lead width, lead length and finger length are also discussed in terms of SM failure rates. Meanwhile, in order to study the failure mechanism, a finite element analysis (FEA) is conducted to evaluate the influences from vacancy migration path, hydrostatic stress gradient and different metal geometries. As a result, a characterization regarding SM at narrow metal finger with wide lead is obtained for the reference of reliability assessment and process improvement.