A novel lead-free solder replacement (original) (raw)
Lead-free solder materials-state of art and perspectives for the future
Lead was until recently a widely used element in many components of the electronics industry. It appears in the solder material, coatings soldered on printed circuit boards, pins and ends of boards. On one hand, the commonness of the electronic equipment which accompanies almost every aspect of our lives (~ 8 million tones of waste per year in EU countries) and on the other hand, great dispersion of lead within it, made Pb recovery and recycling impossible. As a result of wastes, corrosion toxic lead compounds were passing into groundwater and contributing to environmental pollution. Harmful effect of lead on human health is well known -its accumulation in the body causes disorders in the nervous and reproductive systems, the delays in neurological and physical development, anemia and hypertension. In the 90's of the last century Japan and the U.S. began research on the replacements of typical PbSn solders. Among the countries of the European Union breakthrough came about 10 yea...
Springer eBooks, 2016
Driven by RoHS regulation, the world has been migrating toward leadfree soldering since late 1990s. In this chapter, the main stream lead-free soldering practice was presented, and the properties of lead-free solder materials and soldering joints, including intermetallic compounds and microstructure evolution, were exemplified and discussed. Furthermore, the major categories of reliability of solder joints, including temperature cycling, fragility, electromigration, and tin whisker, were described and the mechanism was elucidated. Lastly, the trends and status of novel lead-free solder alloys, including low temperature, low cost and high reliability, and high temperature alloys were briefly introduced and reviewed.
IAEME, 2019
Overview of the current advances in lead-free solder, with highlighting the effects of various alloying elements is discussed in this paper. Also discussed is nanoparticle additions in solder alloy, as new prospects for innovative ways to enhance solder strength and reliability. Developing a high strength solder not containing lead is a challenging task, and we still needs to advance our knowledge of ternary and quaternary lead-free solder systems, from physical metallurgy. This paper discusses various alternative lead-free solders.
Development of alternatives to lead-bearing solders
1993
technology, using tin-lead alloys has had a significant role in the packaging of highly functional, low cost electronic devices. The elimination of lead from ali manufactured products, whether through legislation or tax incentives, will impact the electronics community, which uses lead-containing solders. In response to these proposed measures, the National Center for blanufacturing Sciences has established a multi-year program involving participants from industry, academia, aJld the national laboratories with the objective to identify, potential replacements for leadbearing solders. Selection of candidate alloys is based upon the analysis of materials properties, manufacturability, modeling codes for reliability, prediction, as well as to.,dcological properties and resource availability' data developed irl the program.
IBM Journal of Research and Development, 2005
The replacement of lead (Pb)-bearing solders used in the electronic industry with Pb-free solders will become a reality in the near future. Several promising Pb-free solders have recently been identified, including Sn-0.7Cu, Sn-3.5Ag, Sn-3.8Ag-0.7Cu, and Sn-3.5Ag-4.8Bi (in wt.% with slight variations in composition). These are all Sn-rich solders with melting temperatures between 2108C and 2278C, and are recommended for various soldering applications, including surface mount technology (SMT), plated-through-hole (PTH), ball grid array (BGA), flip-chip bumping, and others. Although a considerable amount of information on Pb-free solders has been published in the last few years, the database on these new materials is still at an infant stage compared with that for Pb-containing solders. This paper addresses several aspects of the current fundamental materials understanding associated with Pb-free solders and various issues regarding their imminent use in electronic interconnect applications, including microstructure-processingproperty relations, mechanical properties, interfacial reactions, and the thermal-fatigue life and failure mechanisms of Pb-free solder joints. ÓCopyright 2005 by International Business Machines Corporation. Copying in printed form for private use is permitted without payment of royalty provided that (1) each reproduction is done without alteration and (2) the Journal reference and IBM copyright notice are included on the first page. The title and abstract, but no other portions, of this paper may be copied or distributed royalty free without further permission by computer-based and other information-service systems. Permission to republish any other portion of this paper must be obtained from the Editor. 1 BT resin-bismaleimide triazine (polymer resin).
NEW TYPES OF LEAD-FREE SOLDERS AND THEIR PROPERTIES
The aim of this work is an experimental study of lead-free solders. Ternary and binary alloys with different ratios of individual elements Ag, Al, Bi, Cu, In, Mg, Sb, Sn and Zn were prepared experimentally. The study of low-fusing solder alloys was performed with the aspect of observing their selected physical, chemical, structural and technological properties. The following characteristics were studied: temperatures and enthalpies of phase transformations (DTA, TG, DSC) of individual solders at the rates of re-heating and cooling of specimens of about 4°C/min, macro-and micro-structural analysis (optical metallography), micro-hardness, chemical analysis: ICP-AES, optical emission spectrometry (OES), X-ray micro-analysis of individual phases in the structure of solders (WDX, EDX), measurement of density and electrical resistivity of selected solders in dependence on the temperature, test of wettability with or without use of fluxes, measurement of corrosion properties.
Lead‐free Solder Pastes Evaluation at Motorola Transmission Products Division
Soldering & Surface Mount Technology, 1995
The increased interest in the electronics industry to search for alternatives to lead‐containing solders is evidenced by the number of recently published articles on lead‐free solders in this journal and other journals. At the latest Surface Mount International conference, several papers were presented on lead‐free solder alloys, conductive adhesives and organic preservatives, all in search of replacements for lead‐containing finishes. The efforts to find a replacement for tin/lead are in response to possible legislation banning lead or possible taxation on the use of lead. In an attempt to reduce the use of lead in this company's assembly operation, five lead‐free solder pastes and four corresponding flux vehicles (for A, B, C and E pastes) were evaluated. All of the flux vehicles passed the standard industry tests except for two flux vehicles (pastes B and C) that failed the copper mirror test. An assembly trial of the lead‐free pastes was carried out by building liquid crysta...
International Journal of Scientific Research in Science, Engineering and Technology, 2022
Soldering properties such as melting temperature and wettability of tin-zinc alloy improved after adding different alloying elements such as indium, aluminum, cadmium and bismuth. Decreasing zinc content (Sn91Zn9) up to 4% (Sn96Zn4 alloy) increased corrosion resistance from -0.847 to -0.530 and decreased corrosion rate from 51.84 to 7.705 mpy. Microstructure of tin-zinc alloy changed with increasing hardness value of it after adding alloying elements. Tin-zinc alloys have lower melting temperature compared to Sn95Sb5, Sn96.5Ag3.5 and Sn99.3Cu0.7 alloys. The Sn90Zn4Bi6 alloy has beast solder properties for electronic industrial applications.
Fundamentals of Lead-Free Solder Interconnect Technology
2015
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