Thermal Cycling Aging Effect on the Shear Strength, Microstructure, Intermetallic Compounds (IMC) and Crack Initiation and Propagation of Reflow Soldered Sn-3.8Ag-0.7Cu and Wave Soldered Sn-3.5Ag Ceramic Chip Components

Andersson, Cristina; Tegehall, Per-Erik; Andersson, Dag; Wetter, Göran; Liu, Johan

doi:10.1109/tcapt.2008.916793

Cited by 19 publications

(12 citation statements)

References 38 publications

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“…[5][6][7][8][9] The Sn-37Pb alloy consists of large, soft, equiaxed Pb islands embedded in a Sn matrix, [6][7][8][9] with grain boundary sliding as the dominant creep mechanism. In comparison, hard IMCs of Ag 3 Sn and Cu 6 Sn 5 embedded around a matrix of soft Sn dendrites in Pb-free solders [10][11][12] probably limit grain boundary sliding (GBS) to some extent in the early stages, and dislocation climb is expected to dominate. [13][14][15][16][17][18] However, GBS may progressively increase as the large Sn grains recrystallize into a finer polycrystalline state due to cyclic fatigue loading.…”

Section: Introductionmentioning

confidence: 99%

“…This variability is expected to be due to the sensitivity of the microstructure of solders to various factors such as the length scale of the test specimen, fabrication process, aging condition, state of damage, and loading conditions. 10,12,39 Hence, in order to assess and benchmark the performance of Pb-free solders relative to that of Sn-37Pb solder, a consistent set of protocols for specimen configuration, specimen fabrication, and test methodology is necessary.…”

Section: Introductionmentioning

confidence: 99%

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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%

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 solder joint is the means through which mechanical equilibrium between the package component and the board is maintained. Hence, at the Tier 4 level, complex evolving boundary conditions are imposed on the actual physical geometry of the solder joint (including the interfacial metallization that creates the intermetallic bond between the solder and the component [13][14][15][16][17]). The next lower length scale (Tier 3) is the grain scale microstructure, typically consisting of an anisotropic single crystal or a few Sn grains and grain boundaries and sometimes a truly polycrystalline microstructure arising from microstructural evolution processes including continuous recrystallization (cRx, based upon dislocation recovery) and primary recrystallization (Rx, involving nucleation and growth of new orientations).…”

Section: Estimating Microstructure Evolution With Modelingmentioning

confidence: 99%

Challenges in Future-Generation Interconnects: Microstructure Again

Lee

Bieler

Kim

et al. 2014

Fundamentals of Lead-Free Solder Interconnect Technology

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The aim of this chapter is not to introduce the packaging technology of the future nor the challenges in specific packaging structure. Rather, it is to review the characteristics of technology on the horizon along with the introduction of materials under consideration, briefly consider possible problems associated with such technology, and stress the need for understanding more on the solder itself. For this, this chapter firstly discusses the need for considering new boundary condition of the interconnects that arise from the use of electronics in harsher environment in a small form factor. It is followed by the discussion on the packaging challenges in higher power devices such as the power handling devices and LEDs. Then, material challenges associated with device miniaturization as well as the increased current density in solder interconnects are presented. Finally, the need for and difficulty in developing multiscale model for solder joint property and its behaviors in packaging structure is briefly discussed in order to reemphasize the urgency of achieving more advanced understanding of the Pb-free solder materials in general. Future Packaging and Next-Generation Interconnects: KeywordsThe keywords for future packaging and next-generation interconnects are smaller form factor, higher performance, flexible in form factor and applications, and lower power consumption than the devices used in today's technology. Demand for such devices emerges as electronic devices are increasingly used in unconventional places, and this trend will only increase in the foreseeable future. Such devices will be designed with miniaturization, wider applications, extreme environments, wearable electronics, low power, flexible, more functionality, vertical stacking and 3D architectures, active thermal management, and high current density as design goals and constraints. Critical issues in relation to the development of such devices include the power device package design, MEMS, 3D wafer-level packages, complex

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“…This system is helpful for examining solder joints but provides little information on crack propagation and initiation, which is crucial for understanding defect behaviour. Besides, finite element modelling (FEM) (Stoyanov et al , 2002; Bailey et al , 2002; Andersson et al , 2008) and prediction of failure period (Popelar, 1998; Guven et al , 2004; Clech et al , 2009) have been developed to study solder joint reliability. Nevertheless, the accuracy of the prediction is bounded by a test data set and the chosen model.…”

Section: Introductionmentioning

confidence: 99%

Through lifetime monitoring of solder joints using acoustic micro imaging

Yang

Braden

Zhang

et al. 2012

Soldering &Amp; Surface Mount Technology

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PurposeThe purpose of this paper is to evaluate the application of an acoustic micro‐imaging (AMI) inspection technique in monitoring solder joints through lifetime performance and demonstrate the robustness of the monitoring through analysis of AMI data.Design/methodology/approachAccelerated thermal cycling (ATC) test data on a flip chip test board were collected through AMI imaging. Subsequently, informative features and parameters of solder joints in acoustic images were measured and analysed. Through analysing histogram distance, mean intensity and grey area of the solder joints in acoustic images, cracks between the solder bump and chip interface were tracked and monitored. The results are in accord with associated Finite Element (FE) prediction.FindingsAt defective bumps, the formation of a crack causes a larger acoustic impedance mismatch which provides a stronger ultrasound reflection. The intensity of solder joints in the acoustic image increase according to the level of damage during the ATC tests. By analysing the variation of intensity and area, solder joint fatigue failure was monitored. A failure distribution plot shows a normal distribution pattern, where corner joints have the lowest reliability and are more likely to fail first. A strong agreement between AMI monitoring test data and FE prediction was observed, demonstrating the feasibility of through lifetime monitoring of solder joints using AMI.Originality/valueThe paper indicates the feasibility of the novel application of AMI inspection to monitor solder joint through lifetime performance non‐destructively. Solder joints' real life conditions can be tracked by an AMI technique, hence solder joint fatigue failure cycles during the ATC tests can be monitored and analysed non‐destructively.

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Thermal Cycling Aging Effect on the Shear Strength, Microstructure, Intermetallic Compounds (IMC) and Crack Initiation and Propagation of Reflow Soldered Sn-3.8Ag-0.7Cu and Wave Soldered Sn-3.5Ag Ceramic Chip Components

Cited by 19 publications

References 38 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

Challenges in Future-Generation Interconnects: Microstructure Again

Through lifetime monitoring of solder joints using acoustic micro imaging

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