The effects of aging on the Anand viscoplastic constitutive model for SAC305 solder

Basit, Munshi; Motalab, Mohammad; Suhling, Jeffrey C.; Lall, Pradeep

doi:10.1109/itherm.2014.6892272

Cited by 80 publications

(7 citation statements)

References 26 publications

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“…As expected, longer aging times prior to cycling resulted in additional plastic work dissipation (and thus more damage accumulation) in the solder joints. Additional FEA runs were performed for other prior aging times using the aging dependent Anand parameters in reference [7]. For example, Figure 19 illustrates the variation of (ΔW) with prior aging time for the 15 mm BGA.…”

Section: Fea Results and Discussionmentioning

confidence: 99%

“…Aging was included by using different values of the 9 Anand model parameters for the various prior aging conditions (reflecting the different initial microstructures prior to thermal cycling). Determination of the aging dependence of the Anand parameters has been discussed in detail in prior work of the authors [7][8]24]. The parameters used in this work for no aging, and 6 and 12 months of prior aging at 125 o C are tabulated in Figure 12.…”

Section: Materials Behavior Modelsmentioning

confidence: 99%

“…Such aging effects are greatly exacerbated at higher temperatures typical of thermal cycling qualification tests. The effects of aging on the constitutive and failure behavior of lead free solder have been extensively investigated by the authors using stress-strain and creep testing of small-scale uniaxial specimens [2][3][4][5][6][7][8], uniaxial and shear fatigue testing [9][10], nanoindentation of joints [11][12], and high rate drop tower tensile testing [13].…”

Section: Introductionmentioning

confidence: 99%

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Thermal cycling reliability of aged PBGA assemblies - comparison of Weibull failure data and finite element model predictions

Basit

Motalab

Suhling

et al. 2015

2015 IEEE 65th Electronic Components and Technology Conference (ECTC)

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Isothermal aging causes detrimental changes in the microstructure, mechanical response, and failure behavior of lead free solder joints in electronic assemblies. These material changes also degrade the reliability of solder joints in assemblies subjected to aging prior to field use. In the current work, we have extended our previous research on the effects of aging on lead free solder material behavior to explore the effects of prior aging on solder joint (board level) reliability in actual assemblies. Our overall objective was to develop new reliability prediction procedures that incorporate aging effects, and then to validate the new approaches through correlation with thermal cycling accelerated life testing experimental data for pre-aged assemblies.Traditional finite element based predictions for solder joint reliability during thermal cycling accelerated life testing are based on solder constitutive equations (e.g. Anand viscoplastic model) and failure models (e.g. energy dissipation per cycle model) that do not evolve with material aging. Thus, there will be significant errors in the calculations with lead free SAC alloys that illustrate dramatic aging phenomena. This work has implemented a theoretical framework for correcting this limitation and including aging effects in the reliability modeling. The developed approach involved the use of: (1) a revised set off Anand viscoplastic stress-strain relations for solder that included material parameters that evolve with the thermal history of the solder material, and (2) a revised solder joint failure criterion that included aging effects. The effects of aging on the nine Anand model parameters were determined experimentally for SAC305 lead free solder as a function of aging temperature and aging time. The revised Anand constitutive equations for solder with aging effects were then incorporated into standard finite element codes. The applied aging-aware failure criterion was based on the Morrow-Darveaux (dissipated energy based, DeltaW) approach, with both the fatigue criterion for crack initiation and the crack growth law incorporating material constants that depend on the prior aging of the solder material. Fatigue data were measured for SAC solder using uniaxial and shear test specimens that were aged for various durations and temperatures prior to cycling.The developed reliability modeling procedure has been applied to a family of assembled PBGA components. In the simulations, the packages were subjected to isothermal aging followed by thermal cycling accelerated life testing. The model were selected to reflect the board surface finish and SAC solder combination. With this approach, good correlation was obtained between the new reliability modeling procedure that includes aging and the entire set of measured solder joint reliability data that includes multiple component sizes, prior aging conditions, and board surface finishes.

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Section: Fea Results and Discussionmentioning

confidence: 99%

Section: Materials Behavior Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal cycling reliability of aged PBGA assemblies - comparison of Weibull failure data and finite element model predictions

Basit

Motalab

Suhling

et al. 2015

2015 IEEE 65th Electronic Components and Technology Conference (ECTC)

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“…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].…”

Section: Introductionmentioning

confidence: 99%

“…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. Good correlations were achieved with the measured lifetimes from references [9][10].…”

Section: Introductionmentioning

confidence: 99%

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

Hasnine

Suhling

Prorok

et al. 2015

2015 IEEE 65th Electronic Components and Technology Conference (ECTC)

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In this work, we have examined the ability of microalloy additions (dopants) to reduce aging effects in solder joints by nanoindentation testing of several sets of doped/non-doped alloys. The investigated solder joint alloys included SAC105, SAC105+Ni, and SAC105+Mn. For the doped alloys, the base SAC105 solder in the PBGA component solder balls was modified by microalloying an additional small amount (< 0.05%) of the dopant material (Ni, Mn, etc.). The tested joints were extracted from 14 x 14 mm PBGA assemblies (0.8 mm ball pitch, 0.46 mm ball diameter) that were part of the iNEMI Characterization of Pb-Free Alloy Alternatives Project. After extraction, the joints were then subjected to various aging conditions at high temperature (0-6 months aging at T = 125 o C). After aging, the joints were loaded in the nanoindentation system, and the load-deformation behavior during indentation was used to characterize the mechanical properties of the solder joints for various aging conditions including modulus, hardness, and yield stress. Using constant force at max indentation, we have also measured the creep response of the aged and non-aged solder joint materials for various stress levels. With this approach, we have been able to quantify aging effects in joints and compare the behavior of the standard and doped alloys.Our results have shown that addition of the microalloy elements significantly reduced the aging degradations of the mechanical properties and creep resistance in the joints. For example, the average reduction of the effective elastic modulus of SAC105 joints was 32.9% with 180 days of aging, while the analogous average reductions were 7.0% and 8.1% for the SAC105+Ni and SAC105+Mn joints. Similarly, the average hardness (yield stress) degradation for the SAC105 joints was 45.9%, while those for the SAC105+Ni and SAC105+Mn were 10.5% and 10.7%, respectively. Finally, the creep rate increased 69.1X for the aged SAC105 joints, while the creep rate degradations for the SAC105+Ni (6.5X) and SAC105+Mn (9.0X) were an order of magnitude smaller. Our findings have also suggested that the addition of Ni was slightly more effective than Mn for the SAC105+X dopants.

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Mechanical Characterization of Power Electronics Solder Materials

Calabretta¹,

Sitta²,

Messina³

et al. 2021

Lecture Notes in Mechanical Engineering

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The effects of aging on the Anand viscoplastic constitutive model for SAC305 solder

Cited by 80 publications

References 26 publications

Thermal cycling reliability of aged PBGA assemblies - comparison of Weibull failure data and finite element model predictions

Thermal cycling reliability of aged PBGA assemblies - comparison of Weibull failure data and finite element model predictions

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

Mechanical Characterization of Power Electronics Solder Materials

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