|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Advanced Microelectronic Packaging, Emerging Interconnection Technology, and Pb-free Solder
||In Situ Studies of Whisker Nucleation Induced by Thermal Strain
||Nupur Jain, Andrew Hitt, Justin Vasquez, Eric Chason
|On-Site Speaker (Planned)
There is still significant controversy about how and why Sn whiskers nucleate. To better understand this, we made measurements which use thermal expansion mismatch to induce strain in Sn samples. In ambient atmosphere studies, we use optical microscopy to measure the whisker density and wafer curvature to monitor the stress. This allows us to quantify the relationship between film stress and nucleation rate. We extend previous studies to different microstructures and compositions to study systems with different rates of strain relaxation. We interpret the measurements in terms of a model that includes a stress-dependent activation energy for nucleation. We have also performed studies in a scanning electron microscope (SEM) in which a heating stage is used to induce strain in the sample. This enables us to measure the microstructure before and after nucleation in order to determine from which grains the whiskers nucleate.
||Planned: Supplemental Proceedings volume