| Summary: | 碩士 === 國立中正大學 === 機械系 === 92 === The most important part of a package is the solder joints between the two electronic components and the Lead-free solder is the major concern for the environmental consideration now. Under the high melting temperature of the Lead-free solder, the flux tends to decompose much fast as the temperature grows and it produces bubbles in the solder balls of the package. In order to see the effects of these bubbles on the package’s performance, we use the Mini-BGA package with SnAgCu solder provided by ChipMOS to undergo the temperature cycling test, -45~125℃. We also calculate the parameters of the Anand model and combine it with FEM software, ANSYS, to investigate the failure mechanism and the influences of the bubbles to the reliability of the package. In this thesis, we will compare the analysis results of the package with solder describing by different model, the Anand model and multilinear kinematic hardening model. The experiment and the simulation both show that cracks cut across the voids as the solder has voids in it. When the solder doesn’t have voids in it, the cracks will propagate along the interface between BT substrate and solder. And the reliability life of the package with voids in its solder joints is shorter than one which doesn’t have voids in it about 15~20％(50%failure criterion). And the simulation also reveals that the packages will perform just like those who don’t have any voids in it as the diameter of the voids is about one-eighteenth of diameter of the solder.
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