PARAMETRIC FINITE-ELEMENT METHOD FOR PREDICTING SHAPES OF 3-DIMENSIONAL SOLDER JOINTS

This paper discusses the application of the parametric finite element method for predicting shapes of three-dimensional solder joints. With this method, the surface of the joint is meshed (discretized) with fin ite elements. The spatial variables (x, y, z) are expanded over each e lement in terms of products of interpolation (blending) functions expr essed in parametric form and element nodal coordinates. The element no dal coordinates which are not constrained by the boundary conditions a re determined by minimizing the potential energy function which govern s the joint formation problem. This method has been employed successfu lly in the past to predict the shapes of two dimensional fillet and ax isymmetric joints. In this paper, the method is extended to three dime nsional problems involving sessile drops formed on a rectangular pad a nd solder columns formed between two horizontal planes and subject to a vertical force.