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Geometric Shape Prediction for a Sn/4.0Ag/0.5Cu (SAC405) Solder Joint After Reflows

The fatigue-induced solder joint failure of surface mounted electronic devices has become one of the most critical reliability issues in electronic packaging industry. Prediction of the shape of solder joints has drawn special attention to the related development and engineering applications. Numerous solder joint models, based on energy minimization principle and analytical methods, have been proposed and developed. The methods are extensively utilized to the shape design of solder joint. However, it is important to find a suitable method to real applications. Herein, a series of experiments with different geometric parameters of SAC405 solder joints were carried out and the results were compared with the prediction by Surface Evolver Program. The changes of geometric shape with respect to different parameters of solder joint were also discussed. The influence of the geometric parameters, such as volume of solder joint, package weight, solder surface tension, and gravity force to the shape of solder joint were investigated.
Two experiments with SAC405 solder balls were carried out. One is to observe the different reflowed geometry shape of solder balls with various volumes, and another is to observe the different reflowed geometry shape of solder balls with various loadings on them. The results show that the models made by Surface Evolver program are very similar to the real shapes observed by experiments, and the differences are between -3% ~ 6.5%. Thus, the results show that the predicted shapes are satisfactorily suitable.
Finally, the predicted models by Surface Evolver program were also put into the ANSYS program, and preceded the fatigue life prediction due to thermal cycling tests. The comparison of the effect on fatigue life with respect to different geometry shapes is illustrated. The results show the shape of solder ball due to high loadings is better than that in thermal cycling tests.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0708108-181854
Date08 July 2008
CreatorsLiu, Kuang-Ting
ContributorsKung, Huang-Kuang, Lai, Yi-shao, Liu, Chorng-Fuh, Jen, Ming-Hwa R., Chen, Ming
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0708108-181854
Rightsrestricted, Copyright information available at source archive

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