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
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Journal ArticleDOI
A design of a new miniature device for solder joints’ mechanical properties evaluation:
Quang Bang Tao,L. Benabou,Laurent Vivet,Ky-Lim Tan,Jean-Michel Morelle,Van-Nhat Le,Fathi Ben Ouezdou +6 more
TL;DR: In this paper, a micro-testing machine is used for evaluating the mechanical properties of solder alloys, showing the influence of strain rate and temperature parameters on their respective mechanical responses.
Journal ArticleDOI
Effect of SrO content on microstructure of Bi2O3-B2O3-ZnO-BaO-SrO low-melting glass frit and joining performance of sodalime glass substrates
L.X. Zhang,Qin Sun,Jintao Wang,Zheng Zhang,Weiwei Zhang,Jianqiang Wang,Hongtao Chen,Mingyu Li +7 more
TL;DR: In this article, the feasibility of using Bi-based lead-free glass paste as bonding material on soda-lime glass substrates, without any activation preparation on the bonding surfaces, was studied.
Journal ArticleDOI
The effects of third alloying elements on the bulk Ag3Sn formation in slowly cooled Sn-3.5Ag lead-free solder
TL;DR: In this paper, the effects of third alloying elements (Cu, In, Zn) on the formation of bulk Ag3Sn intermetallic compounds (IMCs) in slowly cooled Sn-3.5Ag lead-free solder were investigated by microstructural observation and thermal analysis technique.
Journal ArticleDOI
Effect of adding Ce on interfacial reactions between Sn-Ag solder and Cu
TL;DR: In this paper, the effect of adding cerium (Ce) to low Ag content Sn 1.0wt.% solder on the interfacial reactions between the Sn-1.0Ag solder and Cu substrate was investigated.
Journal ArticleDOI
Thermomigration in Co/SnAg/Co and Cu/SnAg/Co sandwich structure
TL;DR: In this article, the authors investigated the thermomigration behavior of Co/SnAg/Co and Cu/Sn Ag/Co sandwich structure and found that Co possesses better thermal properties than Cu and Sn.
References
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