White Papers

Check the box next to each paper you want to download. You may download as many papers as you wish. After selecting papers and completing the contact information form on this page, the paper(s) will be e-mailed to you at the e-mail address you provide.

Papers about electronic

• A Drop-In Lead-Free Solder Replacement

  by Dr. Ning-Cheng Lee, Iris Artaki, James Slattery, John R. Sovinsky, Paul T. Vianco

  Environmental and toxicity concerns related to the use of lead have initiated the search for acceptable, alternate joining materials for electronics assembly. This paper describes a novel lead-free solder designed as a "drop in" replacement for common tin/lead eutectic solder. The physical and mechanical properties of this solder are discussed in detail with comparison to tin/lead eutectic solder. The performance of this solder when used for electronics assembly is discussed and compared to other common solders. Fatigue testing results are reported for thermal cycling electronics assemblies soldered with this lead-free composition. The paper concludes with a discussion on indium metal availability, supply and price.

  pb-free, surface mount, SMT, solder paste, reflow, electronic, lead-free, soldering, solder

  [Permanent Link to this Paper]

  Posted on 1 Jan 2009

• Getting Ready For Lead Free Solders

  by Dr. Ning-Cheng Lee

  This paper reviews the status of lead-free solder developmental works. Some of the solder systems, Bi-Sn, Bi-Sn-Fe, In-Sn, Sn, Sn-Ag, Sn-Ag-Zn, Sn-Ag-Zn-Cu, Sn-Bi-Ag, Sn-Cu, Sn-Cu-Ag, Sn-In-Ag, Sn-Sb, Sn-Zn and Sn-Zn-In are discussed in more details, while the others are briefly commented on. In general, compared with eutectic Sn-Pb solder, all the lead-free solder alternatives investigated more or less exhibit some shortcomings, such as price, physical, metallurgical, or mechanical properties. Relatively, Sn-In-containing systems are more promising in terms of solder mechanical properties and soldering performance, although the price of In may be a concern. Eutectic Sn-Ag solder doped with Zn, Cu, or Sb exhibits good mechanical strength and creep resistance, due to refined microstructure. The Bi-Sn systems doped with other elements may have a niche in the low temperature soldering field. Eutectic Sn-Cu has a good potential due to its good fatigue resistance. Eutectic Sn-Zn system modified with In and/or Ag may be promising in mechanical properties. Finding a lead-free alternative for high temperature solders presents the biggest challenge to the industry.

  solder, soldering, lead-free, electronic, tin, lead, pb-free

  [Permanent Link to this Paper]

  Posted on 4 Mar 2010

• RoHS Recast

  by Dr. Ronald C. Lasky, Krista Botsford

  Even today, its is not widely understood that the fundamental reason that the European Union's Restriction of Hazardous Substances (RoHS) law was put into effect was to support its sister recycling Waste of Electronic and Electrical Equipment (WEEE) law. It is simply much safer, easier and cheaper to recycle electronics equipment that contains little toxic materials. The bill for the industry to convert to RoHS compliant assembly has been estimated at over USD $40 billion, a figure we think is low. RoHS has had the unintended benefit of making uncontrolled recycling of electronic waste in third world countries much safer for workers and environment. National Geographic published an excellent article on this need.

  RoHS, electronic

  [Permanent Link to this Paper]

  Posted on 9 Mar 2010

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