Effect of Sn Grain Orientation on the Cu_6Sn_5 Formation in a Sn-Based Solder Under Current Stressing

摘要

A SnAgCu-based solder stripe between two Cu electrodes is current stressed with a density of 5 x 104 A/cm2 at 393 K (120 °C). After current stressing for 24 hours, electromigration induces the Cu dissolution from the cathode-side Cu electrode, leading to the Cu_6Sn_5 formation in the solder stripe. Very interestingly, the Cu_6Sn_5 phase is selectively formed within a specific Sn grain. Electron backscattering diffraction analysis indicates the crystallographic orientations of Sn grains play an important role in the selective Cu_6Sn_5 formation.