Journal ArticleDOI
Lead-free Solders in Microelectronics
Mulugeta Abtew,Guna S Selvaduray +1 more
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TLDR
The most widely used Pb-free solders have the eutectic composition as mentioned in this paper, which has been identified as a major factor affecting alloy selection, since this will have a major impact on the other polymeric materials used in microelectronic assembly and encapsulation.Abstract:
Practically all microelectronic assemblies in use today utilize Pb–Sn solders for interconnection. With the advent of chip scale packaging technologies, the usage of solder connections has increased. The most widely used Pb–Sn solder has the eutectic composition. Emerging environmental regulations worldwide, most notably in Europe and Japan, have targeted the elimination of Pb usage in electronic assemblies, due to the inherent toxicity of Pb. This has made the search for suitable “Pb-free” solders an important issue for microelectronics assembly. Approximately 70 Pb-free solder alloy compositions have been proposed thus far. There is a general lack of engineering information, and there is also significant disparity in the information available on these alloys. The issues involved can be divided into two broad categories: manufacturing and reliability/performance. A major factor affecting alloy selection is the melting point of the alloy, since this will have a major impact on the other polymeric materials used in microelectronic assembly and encapsulation. Other important manufacturing issues are cost, availability, and wetting characteristics. Reliability related properties include mechanical strength, fatigue resistance, coefficient of thermal expansion and intermetallic compound formation. The data available in the open literature have been reviewed and are summarized in this paper. Where data were not available, such as for corrosion and oxidation resistance, chemical thermodynamics was used to develop this information. While a formal alloy selection decision analysis methodology has not been developed, less formal approaches indicate that Sn-rich alloys will be the Pb-free solder alloys of choice, with three to four alloys being identified for each of the different applications. Research on this topic continues at the present time at a vigorous pace, in view of the imminence of the issue.read more
Citations
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Journal ArticleDOI
Wetting behavior and elastic properties of low alpha SAC105 and pure Sn solder
TL;DR: In this article, low alpha activity solders have been used for soft error in microelectronics packaging and the issue of soft error has necessitated the development of low alpha (LA) activity solder as, as solders are found to be major sources of radiation in electronic devices that causes soft error.
Journal ArticleDOI
Simulation analysis on surface morphology and hysteresis characteristics of molten Sn–3.0Ag–0.5Cu sitting on the inclined Ni substrate
Bingsheng Xu,Zhangfu Yuan,Yan Wu +2 more
TL;DR: Wang et al. as discussed by the authors investigated the interface properties of molten Sn-3.0Ag-0.5Cu solder melting on the inclined Ni substrate at 540k, wetting experiments are performed and the numerical simulation is carried out by Surface Evolver.
Journal ArticleDOI
Textured growth of Cu/Sn intermetallic compounds
TL;DR: In this paper, the growth of intermetallic compounds (IMCs) at the molten Pb-Sn solder/Cu interface was studied over a range of temperatures and for a variety of solder compositions.
Journal ArticleDOI
Microstructure, dynamic restoration and recrystallization texture of Sn-Cu after rolling at room temperature
Guangyu Liu,Shouxun Ji +1 more
TL;DR: In this article, a hypoeutectic Sn-0.5wt%Cu alloy was prepared by casting and subsequent rolling under a moderate strain rate (3.5 × 10−2
Journal ArticleDOI
Effects of small addition of In on the structure of the rapidly cooled Sn–Ag–Zn solder
TL;DR: The effect of small additions of In on the microstructure of the eutectic Sn-3.7-wt.%Ag-Zn-In solder was investigated by microstructural analysis.
References
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