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Experimental Testing and Failure Prediction of PBGA Package Assemblies under 3-Point Bending Condition through Computational Stress Analysis

Reliability test is a very important step for any electronic products before they can be sold to the market. In the previous decades, various types of test have been developed. One of the widely used testing methods is the board bending test. A major issue of performing a reliability test is that numbers of testing samples are required since the test has to be repeated until consistent and satisfactory results can be obtained. A long time will be spent on the specimen design, the assembly processes and the testing procedures. In case the reliability test is not satisfied, the specimen will need to be redesigned, reproduced and retested. This is costly and not efficient from the commercial point of view. To simplify the reliability testing process, computational simulation is proposed to predict the reliability of printed circuit board assemblies (PCBA) at the early design stage. In the present study, 3-point bending test is the reliability test adopted. Finite element model validation and two case studies regarding the application of the model are the objectives of this work. Comparison between experimental results and computational results is carried out for model validation. The physical properties (stiffness and strain) of the model show a good agreement with the experiments at both the elastic deformation stage and the plastic deformation stage under the 3-point bending condition. The maximum von Mises stress at the solder joints of the model at which the samples are found to be failed is also very close to the strength of the solder. This further validates the model. For application, this stress data is used as a failure criterion to indicate whether a PCBA is reliable under different bending conditions