Recrystallization and Precipitate Coarsening in Pb-Free Solder Joints During Thermomechanical Fatigue

Yin, Liang; Wentlent, Luke; Yang, Linlin; Arfaei, Babak; Oasaimeh, Awni; Børgesen, Peter

doi:10.1007/s11664-011-1762-2

Cited by 103 publications

(13 citation statements)

References 39 publications

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“…Yin et al conducted thermomechanical fatigue tests on SAC305 solder balls and proposed a damage accumulation model based on the evolution of microstructural features. This study showed that recrystallization occurs between 25% and 50% of the characteristic life, the remaining time being controlled by crack propagation in the recrystallized area [13]. The evolving microstructure (Ag3Sn coarsening and formation of recrystallized β-Sn grains) during thermal cycling infers an evolution of solder interconnections mechanical properties.…”

Section: Introductionmentioning

confidence: 82%

Microstructural evolutions of Sn-3.0Ag-0.5Cu solder joints during thermal cycling

Libot

Alexis

Dalverny

et al. 2018

Microelectronics Reliability

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Temperature-induced solder joint fatigue is a main reliability concern for aerospace and military industries whose electronic equipment used in the field is required to remain functional under harsh loadings. Due to the RoHS directive which eventually will prevent lead from being utilized in electronic systems, there is a need for a better understanding of lead-free thermomechanical behavior when subjected to temperature variations. As solder joints mechanical properties are dependent of their microstructural characteristics, developing accurate solder joint fatigue models means to correctly capture the microstructural changes that undergo the solder alloy during thermal cycling. This study reports the Sn3.0Ag0.5Cu (SAC305) solder joints microstructural evolution during damaging temperature cycles. Electron BackScatter Diffraction (EBSD) analysis was conducted to assess the SAC305 microstructure corresponding to a specific damage level. Investigated microstructural features included the β-Sn grain size and crystallographic orientation, as well as the grain boundary misorientation and Ag 3 Sn intermetallic compound (IMC) size. As-reflowed and damaged components were also mechanically characterized using nanoindentation technique. The microstructural analysis of SAC305 solder joints prior to thermal cycling showed a highly textured microstructure characteristic of hexa-cyclic twinning with two β-Sn morphologies consisting of preferentially orientated macrograins known as Kara's beach ball, along with smaller interlaced grains. The main observation is that recrystallization systematically occurred in SAC305 solder joints during thermal cycling, creating a high population of misoriented grain boundaries leading to intergranular crack initiation and propagation in the high strain regions. The recrystallization process is accompanied with a progressive loss of crystallographic texture and twinning structure. Ag 3 Sn IMCs coalescence is another strong indicator of SAC305 solder damage since the bigger and more spaced the IMCs are the less dislocation pinning can prevent recrystallization from occurring.

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Section: Introductionmentioning

confidence: 82%

Microstructural evolutions of Sn-3.0Ag-0.5Cu solder joints during thermal cycling

Libot

Alexis

Dalverny

et al. 2018

Microelectronics Reliability

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“…Once a recrystallized microstructure develops, the lifetime of the joint then depends on the rate of crack growth; observations by Yin et al indicate that formation of a recrystallized microstructure takes about ¼ to ½ of the joint lifetime. 55 …”

Section: Trends In Recrystallization and Crack Nucleationmentioning

confidence: 99%

The Role of Elastic and Plastic Anisotropy of Sn in Recrystallization and Damage Evolution During Thermal Cycling in SAC305 Solder Joints

Bieler

Zhou

Blair

et al. 2011

Journal of Elec Materi

109

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Because failures in lead-free solder joints occur at locations other than the most highly shear-strained regions, reliability prediction is challenging. To gain physical understanding of this phenomenon, physically based understanding of how elastic and plastic deformation anisotropy affect microstructural evolution during thermomechanical cycling is necessary. Upon solidification, SAC305 (Sn-3.0Ag-0.5Cu) solder joints are usually single or tricrystals. The evolution of microstructures and properties is characterized statistically using optical and orientation imaging microscopy. In situ synchrotron x-ray measurements during thermal cycling are used to examine how crystal orientation and thermal cycling history change strain history. Extensive characterization of a low-stress plastic ball grid array (PBGA) package design at different stages of cycling history is compared with preliminary experiments using higherstress package designs. With time and thermal history, microstructural evolution occurs mostly from continuous recrystallization and particle coarsening that is unique to each joint, because of the specific interaction between local thermal and displacement boundary conditions and the strong anisotropic elastic, plastic, expansion, and diffusional properties of Sn crystals. The rate of development of recrystallized microstructures is a strong function of strain and aging. Cracks form at recrystallized (random) boundaries, and then percolate through recrystallized regions. Complications arising from electromigration and corrosion are also considered.

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“…The correlation between the damage rate and the work per cycle applies only to isothermal cycling. Failure in thermal cycling is controlled by global recrystallization followed by crack propagation along the new network of grain boundaries [17] and the damage rate appears to scale with the rate of work during the high temperature dwell alone [5]. In contrast, damage in isothermal cycling occurs by transgranular crack growth [18]- [22].…”

mentioning

confidence: 99%

Correlation Between Solder Joint Fatigue Life and Accumulated Work in Isothermal Cycling

Hamasha

Qasaimeh

Jaradat

et al. 2015

IEEE Trans. Compon., Packag. Manufact. Technol.

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The fatigue behavior of solder joints in realistic service applications is still not well understood. Service life prediction based on conducting accelerated tests and extrapolating test results therefore involves a high potential for error. Understanding both the evolution of solder joint properties and the damage accumulation has proved to be critical to reliability modeling. Damage accumulation in isothermal cycling is shown to scale with the accumulated inelastic work even in complex cycling scenarios, so that the life of a solder joint ends upon accumulation of a given amount of work. Individual ball grid array solder joints were cycled in shear fatigue experiments with different load amplitudes and strain rates. The effects of load amplitudes and strain rates on the work accumulation and fatigue life were systematically addressed. The correlation between different loading scenarios and the accumulated work to failure was also discussed. The results showed that the accumulated work until the development of a major crack is constant regardless of the load amplitude. After that the accumulated work to failure is lower for larger load amplitudes. For some reason, a larger fraction of the work appears to be dissipating as heat at lower load amplitude, but only during crack growth. On the other hand, the strain rate affects the fraction of the work going to heat even before the development of a major crack.

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Recrystallization and Precipitate Coarsening in Pb-Free Solder Joints During Thermomechanical Fatigue

Cited by 103 publications

References 39 publications

Microstructural evolutions of Sn-3.0Ag-0.5Cu solder joints during thermal cycling

Microstructural evolutions of Sn-3.0Ag-0.5Cu solder joints during thermal cycling

The Role of Elastic and Plastic Anisotropy of Sn in Recrystallization and Damage Evolution During Thermal Cycling in SAC305 Solder Joints

Correlation Between Solder Joint Fatigue Life and Accumulated Work in Isothermal Cycling

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