Journal ArticleDOI
Lead-free Solders in Microelectronics
Mulugeta Abtew,Guna S Selvaduray +1 more
Reads0
Chats0
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
More filters
Journal ArticleDOI
In situ observations on creep fatigue fracture behavior of Sn–4Ag/Cu solder joints
Qingke Zhang,Z.F. Zhang +1 more
TL;DR: In this article, the deformation morphologies were observed by scanning electron microscopy and the microstructure of the solder was characterized using an electron backscattered diffraction system, and the results showed that the creep fatigue process can be divided into three stages: a strain hardening stage, a steady deformation stage and an accelerating fracture stage.
Journal ArticleDOI
Microstructure and tensile behavior of Sn–5Sb lead-free solder alloy containing Bi and Cu
M.J. Esfandyarpour,Reza Mahmudi +1 more
TL;DR: In this article, the authors investigated the tensile deformation behavior of three binary alloys, namely, Sn-5Sb, SnSb-1.5Bi, and Sn-Sb 1.5Cu alloys at temperatures ranging from 298 to 400 K, and strain rates ranging from 5 −10−4 to 1 −1−10−2 s−1.
Patent
Thermal interface material and solder preforms
Brian G. Lewis,Bawa Singh,John P. Laughlin,David V. Kyaw,Anthony E. Ingham,Attiganal Narayanaswamy Sreeram,Leszek Hozer,Michael James Liberatore,Gerard Minogue +8 more
TL;DR: A thermal interface material having a bonding component and an additive component which is a CTE modifying component and/or a thermal conductivity enhancement component is a thermal preform having multiple layers including a solder layer filled with additives interposed between two unfilled layers as mentioned in this paper.
Journal ArticleDOI
High Melting Pb‐Free Solder Alloys for Die‐Attach Applications
TL;DR: In this paper, the authors used Bi-Ag alloys with Ag contents of up to 12wt.% Ag to substitute for Pb-containing alloys in the high temperature range (T > 260 °C).
Journal ArticleDOI
Wettability of molten Sn–Bi–Cu solder on Cu substrate
TL;DR: In this article, the wetting behavior of a new Sn-Bi-Cu Pb-firee solder on Cu substrate was investigated by sessile drop method under an Ar-H(2) flow in the temperature range from 493 K to 623 K.
References
More filters
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.
Related Papers (5)
Six cases of reliability study of Pb-free solder joints in electronic packaging technology
Kejun Zeng,King-Ning Tu +1 more