UTA Department of Mathematics

Applied Mathematics Seminar

Date/Time/Room: Friday (10/24/2003) at 2:00pm in 304 Pickard Hall

Speaker: Leon Xu, Nokia

"Mechanical and Thermal Challenges in Portable Electronics: A Multi-Objective Optimization Problem"

Abstract: Because of increasing demands of functionality and miniaturization in portable consumer electronics such as mobile phones, the reliability of the electronic packages becomes a major concern in product design. In use of these devices, the electronic packages can be subjected to various mechanical and/or thermal environments. Mechanical/thermo-mechanical failures of interconnects between electronic packages and printed wiring board (PWB) are among the major failure mechanisms. In this study, a simulation-based multi-objective design optimization methodology was developed for improving electronic packaging reliability. It was demonstrated using a generic model of an electronic package on a printed wiring board. The objective for the optimization was to improve the reliability of solder joints under both thermal cycling and bending by optimizing a group of design parameters. A parametric finite element model was developed using ANSYS for both load conditions. To improve the numerical efficiency of the optimization, a multiquadratic response surface method was implemented to approximate the response of finite element simulations for each loading condition. Subsequently, the multi-objective optimization of solder joint reliability was implemented using a Minmax principle on all response surfaces and a Differential Evolution algorithm as optimal search engine, which is capable of finding global minimum when local minima exist. Our study demonstrated that the reliability of the solder joints is significantly improved for this given generic model of electronic package. The proposed methodology can be effectively used in improving the reliability of electronic packages.