Numerical analysis on the influent factors of the interface stress of 63Sn37Pb under the temperature cycle condition

To study the interface stress of 63Sn37Pb under the temperature cycle condition in the QFP package. Viscoplastic finite element model is established based on the Anand constitutive equation. These factors are discussed in this paper, and these influent factors of the interface stress are between 63Sn37Pb weld spot and backing. The results show that the loading rate have very large effect on the interface stress of the 63Sn37Pb weld spot. The greater the rate of temperature load, the greater the stress. The holding time have a certain effect on it, the longer the holding time and the higher the peak of SEQV. Also the cycle index with the increase of it, the interface stress is enlarged. But the influence to the interface stress is weakened with a gradual increase of the cycle index.