Mechanical properties and joint reliability improvement of Sn-Bi alloy

Wang, Jianhui; Wen, Long; Zhou, Jianwei; Chung, Myungkee

doi:10.1109/eptc.2011.6184470

Cited by 12 publications

(3 citation statements)

References 9 publications

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“…It exhibits relatively poor physical properties making it prone to defects such as voids and cracks, which can affect the reliability of solder joints. SnBi solder has low mechanical strength, making it susceptible to external forces and vibrations, leading to phenomena such as electromigration and thermal fatigue that can cause circuit failure [ 7 ]. It is necessary to take effective measures to mitigate the impact of these issues.…”

Section: Introductionmentioning

confidence: 99%

Research Overview on the Electromigration Reliability of SnBi Solder Alloy

Li,

Guo,

et al. 2024

Materials

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Due to the continuous miniaturization and high current-carrying demands in the field of integrated circuits, as well as the desire to save space and improve computational capabilities, there is a constant drive to reduce the size of integrated circuits. However, highly integrated circuits also bring about challenges such as high current density and excessive Joule heating, leading to a series of reliability issues caused by electromigration. Therefore, the service reliability of integrated circuits has always been a concern. Sn-based solders are widely recognized in the industry due to their availability, minimal technical issues during operation, and good compatibility with traditional solders. However, solders that are mostly Sn-based, such as SAC305 and SnZn, have a high melting point for sophisticated electronic circuits. When Bi is added, the melting point of the solder decreases but may also lead to problems related to electromigration reliability. This article reviews the general principles of electromigration in SnBi solder joints on Cu substrates with current flow, as well as the phenomena of whisker formation, voids/cracks, phase separation, and resistance increase caused by atomic migration due to electromigration. Furthermore, it explores methods to enhance the reliability of solder joint by additives including Fe, Ni, Ag, Zn, Co, RA (rare earth element), GNSs (graphene nanosheets), FNS (Fullerene) and Al2O3. Additionally, modifying the crystal orientation within the solder joint or introducing stress to the joint can also improve its reliability to some extent without changing the composition conditions. The corresponding mechanisms of reliability enhancement are also compared and discussed among the literature.

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Section: Introductionmentioning

confidence: 99%

Research Overview on the Electromigration Reliability of SnBi Solder Alloy

Li,

Guo,

et al. 2024

Materials

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“…It is necessary to know the microstructure of the solder matrix and tensile properties after adding Sn to the system to understand the Sn-58Bi solder matrix. The major concern is the brittleness of eutectic Sn-58Bi solder alloy while processing electronic devices [37]. So, there is a need to understand the effect of Sn reinforcement particles on the microstructure and the mechanical properties of the eutectic Sn-58Bi solder matrix.…”

Section: Introductionmentioning

confidence: 99%

Effects of tin particles addition on structural and mechanical properties of eutectic Sn–58Bi solder joint

Bashir

Saad

Rizwan

et al. 2022

J Mater Sci: Mater Electron

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Due to the inherent environmental and health toxicities associated with lead, the use of environmental friendly lead-free solder materials has become an unavoidable trend in the electronic packaging industry. Sn-58Bi alloy is gaining attention for its good material properties such as low melting point, reliability and high tensile strength. The presence of the bismuth-rich phase increases the brittleness of Sn-58Bi alloy. The purpose of this study is to suppress the brittleness of Sn-58Bi alloy by the addition of different wt% (0, 10, 20, 30) of Sn powder. The powder metallurgy method was used to prepare the samples. Scanning electron microscopy and energy dispersive X-ray analysis were done to study the structural properties and a tensile test was done by a universal tensile machine to study the mechanical properties. The results reveal that the Sn particles partially dissolved in the Sn-58Bi solder matrix. The dissolution of Sn particles significantly improved the mechanical strength by 30%, suppressed the brittleness and improved the strain value by 1.3 times.

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“…Furthermore, the problem of hightemperature joints becomes critical, especially in the case of multi-chip package and package-on-package applications. In addition, SAC joints are less reliable than classic PbSn, and the soldering process itself has some disadvantages (Wang et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Reliability studies of InnoLot and SnBi joints soldered on DBC substrate

Skwarek

Illés

Witek

et al. 2018

SSMT

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Purpose This paper aims to investigate the quality and reliability of solder joints prepared from Pb-free alloys on direct bounded Cu (DBC) substrates. Two types of solder alloys were studied: Sn90.95Ag3.8Cu0.7Sb1.4Ni0.15Bi3.0, with a high melting point of 225°C, and Sn42Bi58, with low a melting point of 138°C. Design/methodology/approach Capacitor components of size 1806 were soldered on DBC substrates by using convection reflow soldering and vacuum vapor-phase soldering technologies. A part of the samples was subjected to the thermal shock test. The structure of the solder joints and the content of the voids were investigated using three-dimensional X-ray tomography. The mechanical strength of the joints was evaluated using the shear force test, and the microstructure of the joints was studied on metallographic cross sections by using scanning electron microscopy. Findings It was found that the number of voids is not related directly to the mechanical strength of the solder joints. The mechanical strength of the solder joints depends more on the amount of Ag3Sn precipitation, Au precipitation and the intermetallic layer in the solder joints. In some cases, the thermal shock test caused micro-cracks around the Au precipitation because of a mismatch of Au, AuSn4 and Sn in terms of coefficients of thermal expansion. Originality/value DBC substrates are usually used for power electronics, where the quality of the solder joints is even more important than in the case of commercial electronics.

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Mechanical properties and joint reliability improvement of Sn-Bi alloy

Cited by 12 publications

References 9 publications

Research Overview on the Electromigration Reliability of SnBi Solder Alloy

Research Overview on the Electromigration Reliability of SnBi Solder Alloy

Effects of tin particles addition on structural and mechanical properties of eutectic Sn–58Bi solder joint

Reliability studies of InnoLot and SnBi joints soldered on DBC substrate

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