Development of flip chip solders joint defects under temperature cycling testing

In this paper 3968 bumps were successfully bonded by flip chip method. Then the solder joints of flip chip underwent harsh temperature cycling testing. Industry computed tomography (ICT), optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) were used to analysis the transformation of structure and material of solder joints. After the temperature cycling testing, it was concluded that the solder joints of the flip chip were well arranged and existed obvious deviation from center to edge of the flip chip. Offsets also occurred and the displacement ratio 0.34%. Furthermore, intermetallic compound of solder joint transferred dramatically when the flip chip underwent the temperature cycling testing. The results provided a reliable and efficient way to evaluate solder joint defects for flip chip or other high packaging types.