Dependence of grain orientation in SABI333 solder joints on solidification temperature

摘要

Electron backscattered diffraction was employed to observe the orientations of as-solidified Sn3.0Ag3.0Bi3.0In (SABI333) joints. Unlike other Sn-based solder joints consisting of only one grain or of tricrystals, the SABI333 joints typically consisted of polycrystals. The polycrystals were found to originate from Sn grains with deflections (> 15°) from the [110] and [ $$1ar {1}0$$ 1 1 ¯ 0 ] directions, i.e., the directions in which nucleation tends to occur, and the Bi and In atoms dissolved in the SnAg melt significantly enhanced the deflection. In addition, the orientations of the SABI333 solder joints were highly related to the solidification temperature. Higher solidification temperatures were associated with higher degrees of deviation. Additionally, two types of double tricrystals of Sn formed during solder joint solidification in the SABI333 joints. Although the characteristics of the twinning differed, both types had 80°–90° misorientations. One system featured four orientations of Sn grain twinning with a [100] or [010] axis, while the other one featured perpendicular tricrystals.