SOLDER JOINT DESIGN FOR OPTIMAL MANUFACTURING PROCESS AND FIELD RELIABILITY
Author: Pradeep Lall Company: Motorola Date Published: 4/28/1997
Surface Mount International
Abstract: A methodology has been developed for design of controlled collapse solder joints based on process and reliability requirements. The motivation for development of this methodology is based on the fact that - typically, the process and reliability requirements do not point to a unique solution. The methodology presented in the paper is based on energy minimization and non-linear finite element simulations to address both process and reliability requirements, simultaneously. The process simulations address the final solder joint shape characteristics and the reliability simulations address solder joint life. Both numerical and closed form solutions have been developed and validated versus experimental data. The numerical solutions are based on an energy minimization engine called Surface Evolver and the closed-form solution is based on the energy minimization using a variational approach. A translation interface from Evolver to ANSYS has been written to translate models seamlessly for reliability simulations and simultaneously evaluate process and reliability requirements.