Characterization of aging effects in lead free solder joints using nanoindentation

2013 ◽  
Author(s):  
Mohammad Hasnine ◽  
Muhannad Mustafa ◽  
Jeffrey C. Suhling ◽  
Barton C. Prorok ◽  
Michael J. Bozack ◽  
...  
Keyword(s):  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Aging Effects ◽  
Free Solder

Isothermal Aging Effects on the Mechanical Shock Performance of Lead-Free Solder Joints

2011 ◽  
Vol 1 (5) ◽  
pp. 714-721 ◽  
Author(s):  
Hongtao Ma ◽  
Tae-Kyu Lee ◽  
Dong Hyun Kim ◽  
H G Park ◽  
Sang Ha Kim ◽  
...  
Keyword(s):  
Isothermal Aging ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Mechanical Shock ◽  
Aging Effects ◽  
Free Solder

Investigation of the Effects of High Temperature Aging on Mechanical Behavior and Microstructural Changes in Lead Free Solders

2019 ◽  
Author(s):  
Jing Wu ◽  
Mohammad S. Alam ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Ostwald Ripening ◽  
Solder Joints ◽  
Particle Diameter ◽  
Lead Free ◽  
Average Particle ◽  
Lead Free Solder ◽  
Aging Effects ◽  
Sac305 Solder ◽  
Free Solder

Abstract Aging effects are common in lead free solder joints within electronic assemblies that are exposed to isothermal environments for extended periods. Such exposures lead to evolution of the solder microstructure, which results in changes in the mechanical properties and creep behavior of the solder joints. In our recent investigations, we have been utilizing Scanning Electron Microscopy (SEM) to better understand aging induced degradations. The microstructural evolutions were observed in SAC305 and SAC_Q (SAC+Bi) alloys exposed to isothermal conditions at T = 125 °C for several different regions from several different joints. The microstructures in several fixed regions of interest were recorded after predetermined time intervals of aging, which were 1 hour (up to 24 hours) and 10 hours (up to 150 hours) for the short term aging samples; and 250 hours (up to 2500 hours) for the long term aging samples. Using the recorded images and imaging processing software, the area and diameter of each IMC particle was tracked during the aging process. As expected, the quantitative analysis of the evolving SAC_Q microstructure showed that the particles coalesced during aging leading to a decrease in the number of particles. This caused an increase in the average diameter of the particles of slightly more than 100% for long term aging of 2500 hours. For SAC305, the average particle diameter was found to increase at three times the rate (increase of 200% after 2500 hours of aging). Thus, coarsening of IMC particles was greatly mitigated in the SAC_Q alloy relative to that observed in SAC305. Immediately after reflow solidification, Bismuth rich phases were present in the SAC_Q joints. During aging at T = 125 °C, the bismuth was observed to quickly go into solution both within the beta-Sn dendrites and in the intermetallic rich regions between dendrites. This resulted in solid solution strengthening of the lead free solder. It was also found that the aging-induced presence of bismuth in solution within the beta-Sn matrix provided an increased resistance to the Ostwald ripening diffusion process that coarsens the Ag3Sn IMC particles. The combination of these two effects in the SAC+Bi alloy lead to greatly improved resistance to aging induced effects relative to the SAC305 solder alloy. Finally, we have compared the time dependent evolution of microstructure with the degradation in strength during aging for of the two solder alloys, and good correlations were observed.

Nanomechanical Characterization of Lead Free Solder Joints

2013 ◽  
pp. 11-22 ◽  
Author(s):  
Md Hasnine ◽  
Muhannad Mustafa ◽  
Jeffrey C. Suhling ◽  
Barton C. Prorok ◽  
Michael J. Bozack ◽  
...  
Keyword(s):  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder

Numerical Investigation on Electromigration Oriented Failure of Lead Free Solder Joints With Aging Effects

2019 ◽  
Author(s):  
Tusher Ahmed ◽  
Mohammad Motalab ◽  
Jeffrey C. Suhling
Keyword(s):  
Thermal Aging ◽  
Flip Chip ◽  
Solder Joints ◽  
Mass Diffusion ◽  
Lead Free ◽  
Small Scale ◽  
Time To Failure ◽  
Lead Free Solder ◽  
Aging Effects ◽  
Free Solder

Abstract Lead free solder materials have replaced lead based solder materials nowadays for increased environmental concern. Further miniaturization of electronic solder joints in packages has caused electromigration to dominate among all the reliability issues found in electronic packages. This current investigation deals with the review of mechanical property degradations of SAC305(Sn-96.5Ag-3.0Cu-0.5) solder materials due to thermal aging and their effects on electromigration oriented failure of small scale flip chip solder bumps. Thermal aging causes significant degradation of ultimate strength as well as elastic modulus of the SAC solder material. This degradation in stress-strain relationship plays an utterly important role in electromigration oriented mass diffusion and subsequent failure in the solder joints. This research highlights the linkage between thermal aging oriented strength degradation and its effect on electromigration oriented void propagation rate and time to failure. Structural-electric diffusion analyses with a finite element analysis software have been performed and results derived from different aging conditions (1 to 60 days of aging at 100 °C) at different electromigration temperatures have revealed that mass diffusion due to electromigration and associated stress migration actually reduces with the increment of aging time and thus increases time to failure in case of a flip chip solder joint. Simulation results have been found to be in good agreement with the experimental results available in literatures. These results can pave way to further detailed experimental investigation on effect of thermal aging on electromigration.

Nanomechanical Characterization of Aging Effects in Solder Joints in Microelectronic Packaging

2013 ◽  
Author(s):  
Mohammad Hasnine ◽  
Muhannad Mustafa ◽  
Jing Zou ◽  
Jeffrey C. Suhling ◽  
Barton C. Prorok ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solder Joints ◽  
Bulk Solder ◽  
Lead Free ◽  
Lead Free Solder ◽  
Aging Effects ◽  
Single Grain ◽  
Free Solder ◽  
Aging Phenomena ◽  
Sac Solder

The mechanical properties of a lead free solder are strongly influenced by its microstructure, which is controlled by its thermal history including solidification rate and thermal aging after solidification. Due to aging phenomena, the microstructure, mechanical response, and failure behavior of lead free solder joints in electronic assemblies are constantly evolving when exposed to isothermal and/or thermal cycling environments. Through uniaxial testing of miniature bulk solder tensile specimens, we have previously demonstrated that large changes occur in the stress-strain and creep behaviors of lead free solder alloys with aging. Complementary studies by other research groups have verified aging induced degradations of SAC mechanical properties. In those investigations, mechanical testing was performed on a variety of sample geometries including lap shear specimens, Iosipescu shear specimens, and custom solder ball array shear specimens. While there are clearly aging effects in SAC solder materials, there have been limited prior mechanical loading studies on aging effects in actual solder joints extracted from area array assemblies (e.g. PBGA or flip chip). This is due to the extremely small size of the individual joints, and the difficulty in gripping them and applying controlled loadings (tension, compression, or shear). In the current work, we have explored aging phenomena in actual solder joints by nano-mechanical testing of single SAC305 lead free solder joints extracted from PBGA assemblies. Using nanoindentation techniques, the stress-strain and creep behavior of the SAC solder materials have been explored at the joint scale for various aging conditions. Mechanical properties characterized as a function of aging include the elastic modulus, hardness, and yield stress. Using a constant force at max indentation, the creep response of the aged and non-aged solder joint materials has also been measured as a function of the applied stress level. With these approaches, aging effects in solder joints were quantified and correlated to the magnitudes of those observed in testing of miniature bulk specimens. Our results show that the aging induced degradations of the mechanical properties (modulus, hardness) of single grain SAC305 joints were similar to those seen previously by testing of larger “bulk” solder specimens. However, due to the single grain nature of the joints considered in this study, the degradations of the creep responses were significantly less in the solder joints relative to those in larger uniaxial tensile specimens. The magnitude of aging effects in multi-grain lead free solder joints remains to be quantified. Due to the variety of crystal orientations realized during solidification, it was important to identify the grain structure and crystal orientations in the tested joints. Polarized light microscopy and Electron Back Scattered Diffraction (EBSD) techniques have been utilized for this purpose. The test results show that the elastic, plastic, and creep properties of the solder joints and their sensitivities to aging are highly dependent on the crystal orientation. In addition, an approach has been developed to predict tensile creep strain rates for low stress levels using nanoindentation creep data measured at very high compressive stress levels.

1849 Thermal aging effects on fatigue crack propagation on lead-free solder joints

2005 ◽  
Vol 2005.6 (0) ◽  
pp. 275-276
Author(s):  
Masaki OMIYA ◽  
Satoshi Tsuchiya ◽  
Hirotsugu INOUE ◽  
Kikuo KISHIMOTO ◽  
Masazumi AMAGAI
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Thermal Aging ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Aging Effects ◽  
Free Solder

Intermetallics Characterization of Lead-Free Solder Joints under Isothermal Aging

2008 ◽  
Vol 37 (8) ◽  
pp. 1130-1138 ◽  
Author(s):  
Anupam Choubey ◽  
Hao Yu ◽  
Michael Osterman ◽  
Michael Pecht ◽  
Fu Yun ◽  
...  
Keyword(s):  
Isothermal Aging ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder
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