Finite Element Analysis of Mechanical Stress in Flip Chip Ball Grid Array using ABAQUS

The increased use of area-array technology in electronic packaging recently has given greater importance to the manufacturers of predicting the thermal distribution of area-array solder interconnection. As the interconnection technology for flip chip package is getting finer and smaller and the shape of solder join becomes complex, it is extremely difficult to obtain the accurate stress and strain by direct experimental measurements. Different type of solder balls used for interconnection would also influence the stress effect ofthe package. This paper discussses the results of the mechanical stress load using numerical method via ABAQUS software. A precise 2D finite element model with good quality mesh was constructed to perform 2D plain strain elastoplastic analysis to predict areas of high stress. The analysis was carried out using 20N, 40N, 60N, 80N and 100N respectively on the top of the model. It is found that the bending mechanical stress impact more on outer solder ball compared to the inner solder ball. Other than that, lead-free and leaded solder ball also show different results on the different types of substrate used which are FR-4 and ceramic substrate.