Research on Au-Al bonding properties based on a thermal shock environment

Abstract

The thermal shock experiment of Au-Al bonding has been carried out. The mechanical characteristics, structure morphology and electrical characteristics degradation mechanism have also been researched. No cracks were observed in the bonding interface, and the bonding joints also showed good mechanical characteristics with pull stress of 3.0 to 12.0 g. Due to high temperature, the Au-Al intermetallic compound Au₅Al₂ with high resistibility was formed, which ultimately led to electrical failure. For the samples that were fabricated on the basis of the present technique, the bonding reliability has been evaluated. It has been found that the lifespan rule obeys the Weibull distribution, and at a high temperature of 150?C under 95% confidence level, the estimated results are η = 547 h, m = 3.83. In a room temperature environment, the Au-Al bonding samples  lifespan has also been predicted on the basis of the rule of reliability evaluation. The result shows that the lifespan is about 20 years, while the reliability degree is 90%.