Yuki Fukuda and Michael Osterman
University of Maryland
College Park, MD 20742
The adoption of lead (Pb)-free technology, driven by legislative requirements and market forces, has involved significant changes in materials, processes, and supply chain in electronics industry. The changeover has raised a number of concerns for the electronics industry in assuring product reliability while maintaining reasonable costs. As the European Restrictions of Hazardous Substances (RoHS) deadline of July 2006 approaches, the industry has predominantly settled on tin-silver-copper solder as the replacement for the conventional tin-lead solder. To comply with the RoHS legislation, part manufacturers have sought Pb-free finishes to replace the traditionally used tin-lead finishes. The finish selection is important in providing corrosion resistance, good solderability, and durable solder joints. Currently selected Pb-free finishes include pure tin, tin-bismuth, tin-silver, and tin-copper, to a lesser extent, nickel-palladium-gold (Ni/Pd/Au) and nickel-gold (Ni/Au). Due to low cost and compatibility with existing solders, the pure tin and tin-rich Pb-free alloys have been adopted by a significant portion of the electronic part manufacturers.
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