|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Emerging Interconnect and Pb-free Materials for Advanced Packaging Technology
||Modeling the Growth of Whiskers under Thermally-induced Strain
||Eric Chason, Fei Pei
|On-Site Speaker (Planned)
We describe the results of finite element analysis (FEA) calculations of stress evolution and whisker growth in layers of strained Sn. The simulations include the effects of strain generation (via the applied thermal strain) and strain relaxation (via elasticity, strain-rate dependent plasticity and diffusive whisker growth). We find that the calculated stress evolution is in good agreement with the measurements when we include a mechanism of power-law creep. The simulations also provide good agreement with the measured whisker volume evolution if we include that the stress must be above a critical value for the whisker to grow. In addition, the evolution of the stress distribution explains why the growth rate is proportional to the spatially-averaged stress in the film (as determined by wafer curvature). Although whisker growth relaxes the strain, under the conditions studied most of the plastic strain occurs by the creep mechanism and not by whisker growth.
||Planned: A print-only volume