Elimination of Silicon Electromigration in Contacts by the use of an Interposed Barrier Metal

A RELIABILITY STUDY CONSISTS OF THREE PHASES. THE FIRST PHASE IDENTIFIES A POTENTIAL RELIABILITY PROBLEM (AND THE TEST STRUCTURES). IN THE SECOND PHASE A MATRIX OF STRESS EXPERIMENTS IS CONDUCTED TO DETERMINE ACCELERATION COEFFICIENTS FOR FAILURE MECHANISMS. THE THIRD PHASE THEN USES THE ACCELERATION COEFFICIENTS TO ESTIMATE THE USABLE LIFETIME OF THE PARTS UNDER NOMINAL OPERATING CONDITIONS. HOWEVER, VERIFICATION OF THESE ESTIMATES IS DELAYED BECAUSE OF THE ACTUAL TIME INVOLVED TO GET TO WEAROUT UNDER NORMAL OPERATING CONDITIONS. CLEARLY, THIS LAST PHASE IS THE MOST COMPLEX OF THE THREE.