|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Emerging Interconnect and Pb-free Materials for Advanced Packaging Technology
||Effect of Kirkendall Void Formation in Cu3Sn on Mechanical Properties of IMCs-based Microbumps
||Yaodong Wang, King-Ning Tu
|On-Site Speaker (Planned)
Microbumps are widely used to interconnect Cu-filled through-Si-vias (TSVs) to enable 3D-IC. The diameter of microbumps is about 10 μm, whereas it is 100 μm in controlled-collapse-chip-connection (C-4) solder joints. As the volume of microbump is 1000 times smaller than that of C-4 joint, under a similar processing condition of time and temperature, microbumps can be completely transformed into IMCs of Cu6Sn5 and Cu3Sn. Nevertheless, mechanical properties of IMCs-joint are barely known but it is expected to be brittle. In this study, V-groove-prepared Cu-solder-Cu joint is fabricated for mechanical tests, with joint thickness less than 10 μm to mimic the diameter of microbumps. Thermal ageing was conducted to completely transform Cu6Sn5-dominated joint into Cu3Sn-only IMC-joint. Kirkendall void formation and coalescence in Cu3Sn-joint are microstructurally monitored during ageing. Micro-tensile tests are conducted to measure the degraded adhesion strength due to void growth. Kinetic analysis for IMC-joint evolution will also be provided.
||Planned: A print-only volume