Skip to Main Content Failure mechanisms exposed by environmental
accelerating testing methods such as thermal cycling or thermal
shock test, may differ from those at service operating
conditions. While the device is heated up or cooled down evenly
on its external surface during environmental testing, real
operating powered devices experience temperature gradients
caused by internal local heating, components' different heat
dissipation capability, and ambient temperature variation, etc.
In this study, a power cycling technique is introduced to better
approximate the field operating conditions so as to activate the
field failure modes. Power cycling thermal fatigue test is
performed with different ball grid array solder joints, that is,
lead contained [Sn/37 Pb (SP)] and lead free [Sn/4.0Ag/0.5 Cu
(SAC)], and the result is compared. In order to account for the
thermal fatigue life behavior discrepancy for different solder
joint composition, real time Moire interferometry is applied to
measure the global/local t