An integrated fatigue life prediction methodology for optimum design and reliability assessment of solder interconnections

摘要

An integrated approach is developed for optimum design and reliability assessment of solder interconnections by taking into consideration solder interconnection geometry, thermal and mechanical characteristics of component and printed circuitboard materials, as well as application conditions. For a given design configuration and manufacturing process, solder joint geometry is first predicted; then a macroanalysis is undertaken to estimate the thermal mismatch; and the corresponding thermalstrain and stress on solder joints are estimated by using elastic and creep analyses. Fatigue life is assessed base on an energy-based fatigue failure criterion. A numerical implementation into an integrated analysis tool is pursued in this investigationin such a way that for a given solder joint design and service condition, it provides an efficient way to assess solder joint fatigue life; likewise, for a required service life, it then solves for the optimum solder geometry, and, if needed, points out a way to achieve the optimum thermal matching by intelligent selection of component and substrate materials for any specific service condition.