Real-time monitoring and diagnosis of die attach structure deterioration by using acoustic emission method

In this work, we assembled thermal cycling equipment by a halogen lamp heater and applied the acoustic emission (AE) technique to real-time monitor and diagnose the health state of die attach structures used in power electronics. The assembled equipment is able to execute a cycling environment with a temperature variation from room temperature to 165 °C. Meanwhile, AE monitoring can be applied at the same time to real-time diagnose the health condition of a die attach structure. A soldered die attach structure was tested by 10000 cycles on this platform. AE signals were acquired during the cycling test, which originated from solder layer cracks that were confirmed by scanning acoustic tomography observations. This platform shows a superior specialty in detecting cracking of solder layer due to the high sensitivity of AE monitoring. Meanwhile, the cumulative AE counts that indicate the degree of cracking can be an important indication for diagnosing the health condition of the die attach structure.