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12 SMT Magazine • August 2017 Bismuth (Bi) is a unique element on multi- ple fronts. For your eyes, bismuth can be grown into beautiful iridescent rainbow crystals (Fig- ure 1). When it comes to considering applica- tions in electronics and microelectronics in- dustry, over last three decades, the industry has shied away from using Bi, at least not in stan- dard practices in mass production. However, an interest has surfaced recently. After receiving various questions and com- ments, this series on "The Role of Bismuth (Bi) in Electronics," is tailored to electronics and micro- electronics industry, to provide an overview in its entirety in the areas of importance to indus- try applications going forward. Backdrop The Restriction of Hazardous Substanc- es (RoHS) initiated by the European Commis- sion indeed was impactful, similar to the Mon- treal Protocol—an international treaty agreed in 1987. Both RoHS and the Protocol have had profound impact on the electronics industry. The Protocol phased out the production of sub- stances that are responsible for ozone deple- tion; and RoHS has driven the worldwide im- plementation of lead-free electronics. On lead-free solder materials, our teams through the past two decades have conducted research far before the RoHS becoming effective. Our first patent (Patent Number: 5,520,752) in this area was filed in 1994 and issued in 1996. The patent, jointly owned by the U.S. Army of the Department of Defense and myself, dis- closed Bi-containing lead-free alloys to replace SnPb solder including SnAgBi system, SnAgInBi system, and SnAgCuBi system and other non- Bi-containing lead-free systems. The patent em- bodies the concept and inventiveness of high- performance, lead-free alloys with the objective to serve military electronics. The broad-based awareness of and the indus- try's effort in lead-free alloys started after the RoHS Directive was published by the European Com- by Dr. Jennie S. Hwang H-TECHNOLOGIES GROUP The Role of Bismuth (Bi) in Electronics: A Prelude SMT PROSPECTS & PERSPECTIVES

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