Microstructure evolution and microimpact performance of Sn–Ag–Cu solder joints under thermal cycle test

Abstract

The microstructure and microimpact performance of Sn1Ag0.1Cu0.02Ni0.05In (SAC101NiIn)/AuNi/Cu solder ball joints were investigated after a thermal cycle test (TCT). The joints show complete bulk fracture behavior before TCT. Moreover, TCT facilitated interfacial fracture behavior with lower fracture energy. The intermetallic compounds (IMCs) formed in the solder joints before and after TCT were investigated. TCT induces a variety of structural variations in the solder joints, including slipping bands, whisker formation, the squeezing of the IMC layer, the formation of cavities, the rotation and pop-up of grain, and the deformation and rotation of the entire joint. The variations in fracture behavior induced by TCT are correlated with the structural variations in the solder joints.

Correlative, ML based and non destructive 3D analysis of intergranular fatigue cracking in SAC305 Bi solder balls

“…Hence, the intactness of a solder ball is crucial for the lifetime of the device and its functionality. The fundamental understanding of degradation mechanisms, in particular for more sustainable Pb-free solders remains a vital challenge in the eld of materials science [1][2][3][4][5] . Solder balls serve as both electrical and thermal connections between the chip and printed circuit board (PCB) metallisations.…”

(Invited) Electromigration Reliability of Lead-Free Solder Interconnects

“…Most of the lead-free solders contain more than 95 wt. % Sn, which signifies that the properties of Sn dominate those of lead-free solders [1][2][3][4]. For flip chip (FC) and ball grid array (BGA) technologies, since Cu, Ni and Ni-P are commonly used as under bump metallizations (UBMs), the Cu/solder/Ni, Cu/solder/Ni-P and Ni/solder/Ni-P system are widely applied in solder interconnections.…”