Abstract
We developed a new analysis model for detecting crack propagation in the solder joints for use in LSI packages. In our model, the fatigue life of a solder joint was evaluated based on the damage that accumulated during crack propagation, and the crack paths were automatically calculated. Using the model, we analyzed the effect of displacement amplitude on fatigue crack paths for ball grid array solder joints 0.3mm in the diameter, including a void of 0.1mm at a joint interface. When the displacement amplitude is large, fatigue cracks propagate toward the center of the void. When the displacement amplitude is small, fatigue cracks propagate along the solder joint interface near the void. Large displacement amplitudes increase fatigue life reduction due to void.
