Thermal Residual Stress Field Redistribution, Grain Boundary Void Growth And Electromigration-induced Inclusion Drift In A Bamboo Interconnect

Interconnect failure induced by electromigration, thermal migration and stress migration is of a primary concern in integrated circuits. With the ever-increasing microminiaturization of integrated circuit, metal film interconnect reliability under multi-physical fields has become a more and more important scientific problem. The involution of void and thermal residual stress in the interconnect is the major source of the failure.In the present study, an analytical expression is developed to predict thermal residual stress redistribution in a passivated bamboo interconnect based on coupling of grain boundary diffusion with interconnect passivation interface diffusion. The effects of the microstructure of interconnect, the state of the initial thermal residual stress as well as the diffusivity ratio between the interface and the grain boundary on the stress redistribution are investigated. Furthermore, two analytic expressions to predict grain boundary void growth and thermal residual stress redistribution in a bamboo interconnect with involving void are derived. And the behaviors of the void growth and the stress redistribution are elucidated.Finally, electromigration induced inclusion drift in metal film is studied. An analytical expression is developed to predict elliptical inclusion drift velocity under electromigration. The effects of applied field and inclusion shape on inclusion drift velocity are examined.