GaAs RF Amplifier Field Failure Analysis and Reliability Prediction in 5G AAU System

The paper studies the field failure of a radio frequency differential amplifier in the 5G Active Antenna Unit base station; gallium arsenide(GaAs) die substrate crack was found through failure analysis on the returned units. Packaging process investigation found ejector marks on the blue film were abnormal when executing die bonding. Some amplifiers with slight cracks have passed the functional test, and base station manufacturers’ production test has not effectively intercepted the defect units. Eventually, defect units outflow and fail during field operation. Through the statistics of failure time and reliability data analysis, the results show that the failure is a typical log-normal distribution with a correlation coefficient of 0.87, and the failure rate decreases with time, indicating that the case belongs to an early failure, which once again proves the theory that the early failure is the outflow of defective products. It is estimated that the cumulative failure ratio in 1 year is 0.58% which was confirmed by actual field performance. This study can be a reference for die crack failure analysis and its reliability risk prediction.