A new empirical equation for predicting the thermal-fatigue life of wafer level chip scale package (WLCSP) solder joints on printed circuit board (PCB) is presented. The solder joints are subjected to thermal cycling and their crack lengths at different thermal cycles are measured. Also, the average strain energy density around the crack tip of different crack lengths in the corner solder joint is determined by a time-dependent nonlinear fracture mechanics with finite element method. The solder is assumed to be a temperature-dependent elastic-plastic and a time-dependent creep material.
A New Thermal-Fatigue Life Prediction Model for Wafer Level Chip Scale Package (WLCSP) Solder Joints
Contributed by the Electronic and Photonic Packaging Division for publication in the JOURNAL OF ELECTRONIC PACKAGING. Manuscript received by the EPPD August 7, 2000. Associate Editor: Yi-Hsin Pao.
Lau, J. H., Pan , S. H., and Chang, C. (July 26, 2002). "A New Thermal-Fatigue Life Prediction Model for Wafer Level Chip Scale Package (WLCSP) Solder Joints ." ASME. J. Electron. Packag. September 2002; 124(3): 212–220. https://doi.org/10.1115/1.1462625
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