Via delamination-a novel electromigration failure mechanism

Via delamination, a novel electromigration failure mechanism, has been investigated and understood. The mass transport model, in conjunction with environmental, thermal, and mechanical stresses was proposed to explain this failure mechanism. Process enhancements, which include lowering the thin film stresses and strengthening the adhesion between the tungsten plug/metal stack and metal/inter-level dielectric interfaces, have effectively eliminated this reliability failure mode.