Finite Element Based Thermomechanical Fatigue Analysis of Solder Joints in Electronic Packages

Sağdıç, Hasan
Due to the materials with different thermal expansion coefficients in electronic packages, failures occur with temperature changes. The location of the failure is observed in the solder balls used as joining materials for different components and failure type is crack formation. In this study, thermomechanical simulation and fatigue lifetime calculations of a 144-connection ball grid array (BGA) electronic package made of Sn3.0Ag0.5Cu (SAC305) were performed. For lifetime prediction model Engelmair modified Coffin-Manson method was used. In order to find the geometric configuration of the electronic package with the longest lifetime, a response surface optimization study was performed, including parameters such as under bump metallization (UBM) thicknesses, solder ball diameter and height. Two separate optimization studies were performed, one using the Anand viscoplastic (AV) material model for SAC305 and the other using the Elastoplastic (EP) material model. As a result of the optimization study with the AV material model, a geometric configuration with a 140% increase in lifetime value compared to the original geometry was found, and a configuration with a 163% increase was found with the EP material model. Finally, when the lifetime results of the best configurations from each material model are compared, it is found that the AV material model produces more conservative lifetime results than EP.
Citation Formats
H. Sağdıç, “Finite Element Based Thermomechanical Fatigue Analysis of Solder Joints in Electronic Packages,” M.S. - Master of Science, Middle East Technical University, 2024.