A multi-physics simulation tool is described which has the ability to simulate fluid flow, heat transfer including solidification, and stress evolution in a integrated manner. This modellin framework is used to predict the behavior of two solder materials - the tin-lead eutectic (Sn63Pb37) and Sn95Pb5 - during their solidification and cooling in a copper coated through hole. This integrated modelling approach to both solidification and stress is used to predict the transient anture in which the materials solidify and stress. Comparisons between both materials are given where the low lead content solder is seen to develop higher tensile stress near the solder/pad interface. This may contribute to a defect known as fillet lift.
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