Role of imposed cyclic straining on the stress relaxation behavior of eutectic Sn-3.5Ag solder joints

Rhee, Hongjoo; Subramanian, K. N.; Lee, A.

doi:10.1007/s10854-005-6597-2

Cited by 8 publications

(8 citation statements)

References 18 publications

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“…Creep deformation is manifested as stress relaxation under constantstrain conditions (e.g., during dwell periods of cyclic loads), thereby affecting the durability of SMT assemblies. [1][2][3] Hence, accurate knowledge of the viscoplastic constitutive properties of solders is critical for improved reliability assessment under cyclic creep-fatigue loading. This study focuses on the viscoplastic rate-dependent deformation of undamaged, as-fabricated solder under constantstress conditions (creep test).…”

Section: Introductionmentioning

confidence: 99%

Viscoplastic Creep Response and Microstructure of As-Fabricated Microscale Sn-3.0Ag-0.5Cu Solder Interconnects

Cuddalorepatta

Williams

Dasgupta

2010

Journal of Elec Materi

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The viscoplastic behavior of as-fabricated, undamaged, microscale Sn-3.0 Ag-0.5Cu (SAC305) Pb-free solder is investigated and compared with that of eutectic Sn-37Pb solder and near-eutectic Sn-3.8Ag-0.7Cu (SAC387) solder from prior studies. Creep measurements of microscale SAC305 solder shear specimens show significant piece-to-piece variability under identical loading. Orientation imaging microscopy reveals that these specimens contain only a few, highly anisotropic Sn grains across the entire joint. For the studied loads, the coarse-grained Sn microstructure has a more significant impact on the scatter in primary creep compared to that in the secondary creep. The observed lack of statistical homogeneity (microstructure) and joint-dependent mechanical behavior of microscale SAC305 joints are consistent with those observed for functional microelectronics interconnects. Compared with SAC305 joints, microscale Sn-37Pb shear specimens exhibit more homogenous behavior and microstructure with a large number of small Sn (and Pb) grains. Creep damage in the Pb-free joint is predominantly concentrated at highly misoriented Sn grain boundaries. The coarse-grained Sn microstructure recrystallizes into new grains with high misorientation angles under creep loading. In spite of the observed joint-dependent behavior, as-fabricated SAC305 is significantly more creep resistant than Sn-37Pb solder and slightly less creep resistant than neareutectic SAC387 solder. Average model constants for primary and secondary creep of SAC305 are presented. Since the viscoplastic measurements are averaged over a wide range of grain configurations, the creep model constants represent the effective continuum behavior in an average sense. The average secondary creep behavior suggests that the dominant creep mechanism is dislocation climb assisted by dislocation pipe diffusion.

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Section: Introductionmentioning

confidence: 99%

Viscoplastic Creep Response and Microstructure of As-Fabricated Microscale Sn-3.0Ag-0.5Cu Solder Interconnects

Cuddalorepatta

Williams

Dasgupta

2010

Journal of Elec Materi

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“…Several studies have been conducted on the thermal fatigue behavior of individual solder joints. [9][10][11][12][13][14][15][16] Subramanian and co-workers [9][10][11][12][13] examined the effect of dwell times and ramp rates on the damage accumulation in lap-shear solder/Cu joints. Microstructural analysis showed that faster heating rates resulted in more localized damage, particularly crack formation at Sn grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Thermal Fatigue Behavior of Sn-Rich (Pb-Free) Solders

Sidhu

Chawla

2008

Metall Mater Trans A

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The thermal fatigue resistance of Sn-rich solder joints is dependent on the initial microstructure and damage evolution during thermal cycling. In this study, we have investigated the thermal fatigue behavior of single-lap-shear Sn-rich solder/Cu joints under cyclic thermal loading. Microstructure characterization of the initial and damaged solder-joint microstructures was studied using scanning electron microscopy (SEM). Persistent slip band formation, followed by crack nucleation and propagation at the tip of the lap-shear geometry, took place. The influence of the Sn grain orientation on the thermal fatigue damage was modeled using the finite-element method (FEM). The grain orientation was determined by orientation image mapping (OIM), and a Schmid factor analysis was performed to determine the active slip systems in the Sn grains. It was found that the geometry of the lap-shear joint, rather than the Sn grain orientation, was more significant in determining the location of crack initiation.

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“…Over the last decades, many experiments [1][2][3][4][5][6][7][8][9][10][11] have been done to investigate the effects of the factors mentioned above on the performance of interconnects and solder balls, as well as simulations and experiments combined with modeling. [12][13][14][15][16][17][18][19][20][21][22][23] Here, we only quote a few examples.…”

Section: Introductionmentioning

confidence: 99%

Discussion on the Mechanism of Electromigration from the Perspective of Electromagnetism

Zhou

Johnson

2010

Journal of Elec Materi

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The mechanism of electromigration is discussed from the perspective of electromagnetism, rather than from the traditional view of momentum exchange owing to collisions between electrons and diffusing ions. It is suggested that, from the perspective of conservation of momentum, the momentum transferred to the diffusing ions is related to the Maxwell stress, and the effective charge is proportional to the density of the net charge within the volume element. It is also suggested that, from Poynting's theorem, the energy associated with electromigration is related to the work done by the electric field, and the conversion of the nonelectrostatic energy from the electric power source into the chemical energy of the diffusion system. From both perspectives, the effective driving force can be shown to have a square dependence on the current density. Therefore, it is suggested that the effective charge number is linearly related to the current density.

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Role of imposed cyclic straining on the stress relaxation behavior of eutectic Sn-3.5Ag solder joints

Cited by 8 publications

References 18 publications

Viscoplastic Creep Response and Microstructure of As-Fabricated Microscale Sn-3.0Ag-0.5Cu Solder Interconnects

Viscoplastic Creep Response and Microstructure of As-Fabricated Microscale Sn-3.0Ag-0.5Cu Solder Interconnects

Thermal Fatigue Behavior of Sn-Rich (Pb-Free) Solders

Discussion on the Mechanism of Electromigration from the Perspective of Electromagnetism

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