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CSME 2021/10
Volume 42 No.5
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451-459
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Modified Inverse Algorithm for SAC305 Solder Joint Life Prediction
Ning Luoa, Ching-I Chenb and Hong Xing Qiuc
aSchool of Mechanical and Automotive Engineering, Xiamen University of Technology, Xiamen 361024, China. / Ph. D. Program in Engineering Science, Chung Hua University, Hsinchu 30012, Taiwan
bDepartment of Mechanical Engineering, Chung Hua University, Hsinchu 30012, Taiwan
c3DFAMILY Technology Co., Ltd., New Taipei 23674, Taiwan
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Abstract:
To predict the lifetime of the SAC305 solder joint in thermal shock test and temperature cycling test, a suite of wafer-level chip-scale packages (WLCSPs) were investigated by experiments and finite element simulations. Due to the insufficient experimental life data provided by the manufacture, a three-step modified inverse algorithm is adopted. First, Sn95.5Ag3.8Cu0.7 solder joints were simulated, and the lifetime were evaluated to check the consistency between the experimental and simulated lifetimes. Second, discrepant life was modified by analyzing the correlations of the life fatigue indices in the finite element simulation, thus providing the absent experimental life data. Third, life prediction models of SAC305 Anand constitutive material were developed based on the accumulated creep strain energy density and accumulated creep strain. Finally, the SAC305 life prediction model was verified in a solder joint experiment on another WLCSP. The lifetimes obtained by the model and the new experiment differed within 8%.
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Keywords: SAC305, Life Prediction Model, Finite Element Method, Fatigue Index
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©
2021
CSME , ISSN 0257-9731
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