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
The effects of temperature and solders on the wettability between ribbon and solar cell
TL;DR: In this article, the sessile-drop method was applied to measure the wettability of two lead SnAgPb (SAP) solders and a lead-free SnAgCu (SAC) solder on two Ag paste substrates at temperature ranging from 190 to 280°C.
Journal ArticleDOI
Low cycle fatigue and fatigue crack growth behaviour of Sn–Ag eutectic solder
TL;DR: The link up of these cracks and the propagation of cracks inside the specimen occurred both transgranularly through Sn-Ag eutectic phases, and intergranularally along Sn-dendrite boundaries and/or subgrain boundaries as discussed by the authors.
Journal ArticleDOI
Solution Synthesis of Monodisperse Indium Nanoparticles and Highly Faceted Indium Polyhedra
TL;DR: In this paper, a simple and effective synthetic method to prepare monodisperse indium metal nanoparticles less than 10 nm in size via a simple lithium borohydride reduction method conducted in amine based solvents.
Journal ArticleDOI
Recrystallization induced by subgrain rotation in Pb-free BGA solder joints under thermomechanical stress
Jing Han,Fu Guo,Jianping Liu +2 more
TL;DR: In this article, the grain orientation evolution of Sn3.0Ag0.5Cu ball grid array (BGA) solder joints under thermomechanical stress was characterized quantitatively using electron backscatter diffraction (EBSD).
Journal ArticleDOI
Reliability studies of Sn–9Zn/Cu and Sn–9Zn–0.06Nd/Cu joints with aging treatment
TL;DR: In this paper, the microstructures and properties of soldered joints with aging at a constant temperature 150°C for different hours were studied, and it was found that the microstructure of Sn-9Zn-0.06Nd solder aged for 240h remarkably changed and formed a combination net of Sn grains due to diffusion and aggregation of rare earth element Nd.
References
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Journal ArticleDOI
Quantitative assessment of worldwide contamination of air, water and soils by trace metals
Jerome O. Nriagu,Jozef M. Pacyna +1 more
TL;DR: Calculated loading rates of trace metals into the three environmental compartments demonstrate that human activities now have major impacts on the global and regional cycles of most of the trace elements.
Book
Principles and prevention of corrosion
TL;DR: In this article, the technology and evaluation of Corrosion is presented, with a focus on the effects of Metallurgical Structure on Corrosions, and a discussion of materials selection and design.
Book
Physical Metallurgy Principles
TL;DR: Physical Metallurgy Principles as mentioned in this paper is intended for use in an introductory course in physical metallurgy and is designed for all engineering students at the junior or senior level and is largely theoretical, but covers all aspects of physical metelurgy and behavior of metals and alloys.
Journal ArticleDOI
Interdiffusion and Reaction in Bimetallic Cu-Sn Thin Films
TL;DR: In this article, a Seemann-Bohlin diffractometer was used to investigate interdiffusion and intermetallic compound formation in Cu-Sn thin film couples.
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