Solder Shape Prediction and Residual Stress Evaluation of BGA Solder Joint

Abstract

In this paper, prediction methods of solder joint shape, such as solder joint height and contact angle, for BGA package, which is effective on high density packaging, are studied. Various calculation methods to predict the solder joint shape are studied, and results of the calculation are compared to experimental results to confirm the validity of each calculation methods. Approximate polynomial of solder joint shape, such as solder joint height and contact angle are induced by combining numerical differential method and response surface method using orthogonal table. Next, FEM calculation of board warpage are analyzed to evaluate residual stress in solder solidification process.