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Role of Bismuth in Lead-free Systems - All You Need to Know

Presenter: Jennie S. Hwang, Ph.D.
Company: H-Technologies Group
Date Published: 3/22/2017

Description: Only the slides (PDF) are available for this presentation. The original audio will not be distributed.
Bismuth (Bi), which is introduced either through the supply chain or by design, is becoming an inevitable element in lead-free electronic products. With the deliberation of all relevant parameters, theoretical and practical, Bi plays a “potent” role in electronic solder systems. The proper use of Bi can profoundly benefit the performance and reliability of electronic package and assembly including solder joint performance, tin whisker mitigation, among others. An adequate understanding of the properties and performance parameters of Bi is critical to product reliability. This webtorial will discuss the relevant aspects of Bi to help dispel misconceptions and to demonstrate performance criteria related to Bi. The goal is to help achieve the desired level of performance and product reliability. Your questions and issues for solutions and discussions are welcome.

Main topics for Part 1:

  • Your issues & concerns related to Bi
  • Bi - characteristics, resources, safety data
  • Bi effects in 63Sn37Pb solder joint
          --Physical properties
          --Mechanical behavior
  • Effects of Bi from component coating and PCB surface finish
          --Dissolving into solder joint
          --Estimation of concentration of Bi in solder joint
          --Effect of compositional change

  • Bi effects in SAC solder joint (SnAgCuBi)
          --Compositional change
          --Stress vs. strain
          --Fatigue behavior
  • Bi effects in other Pb-free alloys (SnCu, SnAg, SnAgIn)
          --Stress vs. strain
          --Fatigue performance

    Main topics for Part 2:

  • Historically established Bi-containing electronic solder alloys
  • Bi-containing Pb-free solder alloys
          --Melting temperature range
          --Compositional control level
          --Physical, mechanical properties
          --BGA thermal fatigue performance
  • PCB through-hole fillet-lifting vs. Bi
  • Low temperature BiPbSn phase
          --Presence or absence
          --Detectable or non-detectable effects
          --General guidelines
  • Design limit in Pb-free solder joints vs. solder joint reliability
  • Concluding points
  • Who Should Attend:
    The webtorial provides a working knowledge to all who are involved with or interested in solder joint reliability and system integrity with and without the presence of Bi and related issues in electronic packages and assemblies including designers, engineers, researchers, managers and business decision makers; also is designed for those who desire the broad-based information on the subject.

    Dr. Hwang, a pioneer and a major contributor to the implementation of Surface Mount manufacturing since its inception as well as to lead-free electronics, brings to the webinar her 35+ years experience in hands-on production and as an advisor to OEMs, EMS and government programs. She has provided solutions to many challenging problems - from production yield to field failure diagnosis to high reliability issues. She has received numerous honors/awards including the U.S. Congressional certificate of recognition, induction into WITI International Hall of Fame, named "R&D Star-to-Watch" by Industry Week, YWCA Women of Achievement Award; induction into the National Academy of Engineering. She is the author of 450+ publications and several ground-breaking books on SMT manufacturing and lead-free technology and implementations, and is an invited speaker in numerous international and national events. Additionally, she has served on the Board of NYSE Fortune 500 companies, and on various civic, government and university boards and committees. She chairs the Board of the Assessment of Army Research Laboratory of DoD, of the National Institute of Standard and Technologies, and has been an advisor and a reviewer of government programs (DoD, NASA, NIST, etc.) and various publications. She also serves on the National Manufacturing and Materials Board, Laboratory Assessment Board, and Board of Army Science & Technology. Her formal education includes Harvard Business School Executive Program and four academic degrees (Ph.D. in Metallurgical Engineering & Materials Science, M.S. in Physical Chemistry, M.S. in Liquid Crystal Science, B.S. in Chemistry). She has held senior executive positions with Lockheed Martin Corp., SCM Corp, Sherwin Williams Co, and IEM Corp. She is president of H-Technologies Group and is also an invited distinguished adj. Professor of Engineering School of Case Western Reserve University, and serves on the University's Board of Trustees.

    Key Words: 

    Bismuth, Lead-Free, reliability, solder alloys

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