Abstract
Temperature cycle and vibration is a major fatigue factor of solder joints of the semiconductor package. Many studies have been made for prediction of fatigue life of each case. On the other hand, assessing multiple fatigue factor at the same time is difficulty. We propose an electromotive force method based on the Seebeck effect, because this method can evaluate solder joints directly. In order to clarify the relationship of fatigue and electromotive force, some result of a shear test of Sn-3.0mass%Ag-0.5mass%Cu solder joints is shown in this paper. Maximum electromotive force decreased whenever gave shear load on the specimen. This means that maximum electromotive force is reduced according to the solder joints portion is increased fatigue. This is why estimating formula of fatigue life of solder joints by monitoring the value of the electromotive force is established.
