A Canary Design to Monitor Electromigration of Solder Joints

Electromigration-induced failure has become one of the most serious problems in solder joints. In this paper, a canary device has been designed to monitor the eletromigration of solder joints. Then the current of the canary device is calculated. The canary solder joints are identical to those used in the host circuit but suffered properly larger environmental stress to accelerate aging so they are supposed to fail before those in the host circuit. For this reason the canary device are designed to be sacrificial, and are not used in the circuit. Instead it is packaged separately in order not to influence the normal operation of the host circuit. How to apply sufficient, but not overly large, stress current to the canary device to enhance its electromigration failure without stressing other part of the circuit becomes one of the problems we need to solve. In this paper a canary circuit is designed to solve this problem. Also the increased stress we need was calculated. With the help of the canary device , we can be warned before the solder joints fail to ensure the system health.