Significant effect of orientation on Cu₆Sn₅ coarsening behavior in isothermal aging process

Intermetallic compound (IMC) formed on (001) and (111) Cu single crystal has strong orientation and texture characteristics. The special interface morphology and uniform orientation provide a direction for the regulation of IMC growth behavior. In this study, the significant effect of orientation on Cu₆Sn₅ growth behavior in isothermal aging process was investigated. Synchrotron radiation technology and high pressure air blowing methods were employed to obtain the growth kinetics and the morphology of Cu₆Sn₅ during the heat preservation stage. The results indicate that scallop-like Cu₆Sn₅ grains were formed in heat preservation stage. These grains exhibited an abnormal coarsening behavior that their average diameter at a high temperature of 300 °C was smaller than that at a low temperature of 250 °C after aging for 30 min. Besides, the growth orientation and kinetic controlling factor of these interfacial Cu₆Sn₅ also changed with the increase of reaction time, which was closely related to the appearance of the abnormal coarsening phenomenon. These results are significant and meaningful to the electronic packaging industry.