Mechanical strength test method for solder ball joint in BGA package

Abstract

Ball shear tests were investigated in terms of effects of test parameters, i.e. shear height and shear speed, with an experimental and non-linear finite element analysis in order to evaluate the solder joint integrity of area array packages. The substrate was a common SMD type with solder bond pad openings of 460 Pm in diameter. Microstructural investigations were carried out using SEM, and the IMCs were identified with EDS. It was observed that increasing shear height, at fixed shear speed, results in decreasing shear force, while the shear force increased with increasing shear speed at fixed shear height. Excessive shear height could cause some detrimental effects on the test results such as unexpected high standard deviation values or shear tip sliding from the solder ball surface. Low shear height conditions are favorable for screening the type of brittle interfacial fractures or degraded layers in the interfaces.

Failure mechanism of Pb-bearing and Pb-free solder joints under high-speed shear loading

“…However, the shear speed, which is the displacement rate of a shear ram, has not yet been fully standardized with only a range being specified for the shear speed from 0.01 m/s to 1 m/s for the high-speed shear test. In our previous studies considering the effect of the shear speed in the low-speed shear test, we confirmed the significant effects exerted by this parameter on the shear force value and failure mode [8][9][10]. Therefore, the effect of this parameter on the high-speed shear test needs to be systemically investigated to elucidate the failure behaviors of the solder joints and their mechanisms under high-speed loading.…”

Microstructure and Mechanical Properties of Sn–0.7Cu Flip Chip Solder Bumps Using Stencil Printing Method

“…Therefore, from the joint reliability point of view, it is very important to study the Cu-Sn IMC layer growth kinetics when high temperature storage or extended bake-out creates thick IMC layers. 15,16) As can be seen in the Fig. 1 after the aging time of 2400 h. Some particles of Cu 6 Sn 5 which should be reaction products between Sn and Cu atoms within the bulk solder were found to distribute at the bulk solder region.…”

Cu6Sn5 Morphology Transition and Its Effect on Mechanical Properties of Eutectic Sn-Ag Solder Joints

“…22 As a result of the higher strength of interfacial IMCs compared with the solder matrix, 23 the interfacial IMCs would strongly affect the plastic deformation and crack propagation during the shear test. In addition, because the connection between the solder and substrates occurs mainly through the interfacial IMCs formed by the Fig.…”

“…According to Kim's simulation results of shear tests at different shear heights, the strain was densely accumulated in the right section above the interfacial IMC layer at a shear height of 10 lm, while it is spread out in the upper region of the solder at a shear height of 120 lm. 22 Thus, the results were determined by the microstructure of the solder matrix if the shear height was large and more dependent on the interfacial IMC layer in the case of a lower shear height. Therefore, shear tests at 10-lm and 120-lm shear height were conducted to examine the effects of solder microstructure and the interfacial IMCs on the joint strength.…”