Reduction of lead free solder aging effects using doped SAC alloys

Cai, Zijie; Zhang, Yifei; Suhling, Jeffrey C.; Lall, Pradeep; Johnson, Richard W.; Bozack, Michael J.

doi:10.1109/ectc.2010.5490796

Cited by 112 publications

(26 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After this point, the variations are small and can be fit with a linear decay. These observations are in agreement with our aging results for testing of larger solder tensile specimens [4][5][6]. In addition to the nanoindentation results from the current paper, we have added our prior tensile testing results (blue curve) to the effective modulus data in Figure 10.…”

Section: Effect Of Aging On Elastic Modulus and Hardnesssupporting

confidence: 92%

“…The corresponding degradations of the hardness over the same period were 39.80%, 42.06%, 43.12% and 45.92%. These percentage reductions with 180 days of aging at 125 C are on the same order as those observed for the elastic modulus (51.00%) and yield stress (43.32%) of SAC105 measured by tensile testing of larger multi-grain uniaxial samples in our prior aging investigations [4][5][6]. The uniaxial samples from prior investigations have been examined using polarized light microscopy, and are known to contain hundreds of grains with a variety of orientations.…”

Section: Effect Of Aging On Elastic Modulus and Hardnessmentioning

confidence: 54%

“…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%

“…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%

See 3 more Smart Citations

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)

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Effect Of Aging On Elastic Modulus and Hardnesssupporting

confidence: 92%

Section: Effect Of Aging On Elastic Modulus and Hardnessmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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)

Self Cite

View full text Add to dashboard Cite

show abstract

“…15,16 In Ref. 17, the impact of isothermal aging on mechanical properties of SAC alloys was studied. Modern electronic devices are subjected to severe thermal conditions varying up to 175°C.…”

Section: Introductionmentioning

confidence: 99%

Impact of Thermal Aging on the Microstructure Evolution and Mechanical Properties of Lanthanum-Doped Tin-Silver-Copper Lead-Free Solders

Sadiq

Pesci

Cherkaoui

2013

Journal of Elec Materi

View full text Add to dashboard Cite

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. An extensive study is made to analyze the impact of pure lanthanum on the microstructure and mechanical properties of Sn-Ag-Cu (SAC) alloys at high temperatures. Different compositions are tested; the temperature applied for the isothermal aging is 150°C, and aging times of 10 h, 25 h, 50 h, 100 h, and 200 h are studied. Optical microscopy with cross-polarized light is used to follow the grain size, which is refined from 8 mm to 1 mm for as-cast samples and is maintained during thermal aging. Intermetallic compounds (IMCs) present inside the bulk Sn matrix affect the mechanical properties of the SAC alloys. Due to high-temperature exposure, these IMCs grow and hence their impact on mechanical properties becomes more significant. This growth is followed by scanning electron microscopy, and energy-dispersive spectroscopy is used for elemental mapping of each phase. A significant refinement in the average size of IMCs of up to 40% is identified for the as-cast samples, and the coarsening rate of these IMCs is slowed by up to 70% with no change in the interparticle spacing. Yield stress and tensile strength are determined through tensile testing at 20°C for as-cast samples and after thermal aging at 150°C for 100 h and 200 h. Both yield stress and tensile strength are increased by up to 20% by minute lanthanum doping.

show abstract