|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Emerging Interconnect and Pb-free Materials for Advanced Packaging Technology
||Thermocycling Stress Induced Slip Band Sliding in Ultra-thin ENEPIG Joints
||Tzu-Ting Chou, Cheng-Ying Ho, Wei-Yu Chen, Jenq-Gong Duh
|On-Site Speaker (Planned)
The lead-free solder joints reflowed with ultrathin electroless Ni/electroless Pd/immersion Au (ultrathin ENEPIG) under-bump metallization show distinct failure mode as compared to traditional ENEPIG joint. The ultrathin ENEPIG joint exhibit larger Sn grain size and less grain boundaries that differ from common beach ball structure. Generally, the deterioration occurs along grain boundaries because of mismatch in coefficient of thermal expansion between beta-Sn grains. Due to lack of grain boundaries to release cycling thermal stress, the failure in ultrathin-ENEPIG joints is dominated by slip band sliding of Sn system. The sliding phenomena occurred within the Sn grain was evaluated, showing the trend on the (110) plane along  direction. This study demonstrates that how the cycling thermal stress affects the slip band degradation in ultrathin ENEPIG solder joints.
||Planned: Supplemental Proceedings volume