Isothermal Aging Effects on the Thermal reliability Performance of Lead-Free Solder Joints

Abstract

Recently, an intermittent hot-pressing process had been developed and applied to produce bamboo bundle laminated veneer lumber (BLVL) joints with lengths of more than 6 m. According to our previous studies, there was a major difference in the physical and mechanical performance of hot-pressing joints and at adjacent positions on the lumber. In this paper, heat transfer and the effects of various aging temperatures on the mechanical performance of the joints of intermittent hot-pressed BLVLs were studied. During the hot-pressing process, there were noticeable different temperature changes on the board. In addition, degradation of the modulus of elasticity (MOE) and modulus of rupture (MOR) values on the joints was greater than that on the adjacent positions of the BLVLs, and the degradation increased with increasing aging temperature. Because of the low interfacial bonding strength of the joints caused by the pre-curing effect during the hot-pressing process, the MOR was more sensitive to hydrothermal conditions. Therefore, when BLVLs produced by intermittent hot-pressing are used as engineering components, the joints should be well-designed and arranged to avoid being used in the same cross-section.

Nanomechanical characterization of SAC solder joints - reduction of aging effects using microalloy additions

“…Motalab, et al [11][12][13] have included aging effects in the Anand constitutive model and energy density based failure criterion for SAC solders, and then used these theories with finite element analyses to predict the thermal cycling life of aged BGA assemblies. Good correlations were achieved with the measured lifetimes from references [9][10]. Finally, Lall, et al have studied the high strain rate behavior of SAC solders subjected to aging [14].…”

“…Aging effects on the constitutive and failure behaviors of lead free solders have been studied extensively by the authors and their coworkers [2][3][4][5][6][7][8][9][10][11][12][13][14]. In early investigations, the mechanical properties and creep behavior of SAC alloys were shown to be severely degraded by prior exposure to room temperature (25 C) and elevated temperature (50, 75, 100, and 125 C) aging [2][3][4][5][6].…”

“…Using the developed approaches, the influence of aging on the fatigue life of lead free alloys was also examined [8]. Zhang and coworkers [9][10] have shown that large reductions in the thermal cycling reliability of BGA test assemblies occurs when they are subjected to aging prior to accelerated life testing. Motalab, et al [11][12][13] have included aging effects in the Anand constitutive model and energy density based failure criterion for SAC solders, and then used these theories with finite element analyses to predict the thermal cycling life of aged BGA assemblies.…”

Reliability Comparison of Aged SAC Fine-Pitch Ball Grid Array Packages Versus Surface Finishes

“…Table I summarizes the characteristic life (η from Weibull plot) and provides a comparison between packages. In general, Pb-free solder with ENIG and ENEPIG outperform ImAg under identical test conditions; in addition, the SAC305 solder alloy performs better than SAC105 in all test groups, which compares favorably with [4]- [7]. The characteristic life for no aging 10-mm SAC105 solder on ImAg, ENIG, and ENEPIG were 2419, 3422, and 3536 cycles, respectively.…”

“…Only limited attention has been paid to the effect of package characteristic lifetime reliability during long-term isothermal aging at elevated temperatures, which is the focus of this paper. Zhang et al [4]- [8] and Hai et al [9] concluded that a drastic reduction on packaging reliability occurs during isothermal aging for fine-pitch ball grid array (BGA) packages with Sn-1.0Ag-0.5Cu (SAC105), Sn-3.0Ag-0.5Cu (SAC305), and Sn-37Pb solder ball interconnects. The trends were in the expected directions; namely, the reliability was reduced when using higher aging temperatures, smaller solder balls, and lower Ag-content alloy, since creep deformation is known to operate principally on grain and/or phase boundaries.…”