This is BIG!
SOURCE: National Electronics Manufacturing Initiative
NEMI Group Recommends Tin/Silver/Copper Alloy as Industry Standard for Lead- Free Solder Reflow in Board Assemblies
HERNDON, Va., Jan. 24 /PRNewswire/ -- The National Electronics Manufacturing Initiative (NEMI) today announced the alloy its Lead-Free Assembly Project is recommending for use by industry as a ``standardized' lead- free solder alternative.
For reflow applications (which represent at least 70% of all board assembly production), the NEMI group is recommending Sn3.9Ag0.6Cu -- a predominantly tin-rich alloy with 3.9% silver and 0.6% copper. For wave solder production (which requires larger amounts of solder), the group is recommending either Sn0.7Cu, a less expensive tin/copper alloy (0.7% copper), or Sn3.5Ag (tin with 3.5% silver).
Based on findings of its 1998 roadmap, NEMI organized an industry task force in early 1999 to investigate process and material considerations of lead-free electronics assemblies. The task force investigated past efforts and developed a program to address lead-free electronics manufacturing solutions. The first step of this program, which is being implemented by NEMI's Lead-Free Assembly Project, was to evaluate, select and recommend a single lead-free solder alloy to pursue as an industry standard.
``Task force participants felt strongly that it would be of significant benefit to industry to focus on one standard alloy for replacing lead in solder,' says Jim McElroy, executive director and CEO of NEMI. ``By cooperatively developing a single solution, the industry can implement a replacement sooner, avoid multiple manufacturing processes and, by concentrating on one alloy, enhance basic understanding of the material and assure its reliability.'
The Lead-Free Assembly Project found no drop-in replacement for tin/lead solder. The group compiled a worldwide patent database of candidate alloys and collected all available material properties. In addition to information compiled or generated by the group, data was obtained from two industry reports: the final report of the NCMS (National Center for Manufacturing Sciences) Pb-Free Solder Project, a $10.3M in-kind program performed in the US between 1993 and 1997 (http://www.ncms.org/3portfolio/1ProjectPortfolio/pubs.htm), and a report on lead-free soldering from the U.K. Department of Trade and Industry (http://www.dti.gov.uk).
Based on thorough analysis of the data collected, the most promising solutions for the types of high-reliability products made by the majority of North American electronics manufacturers were combinations of tin, copper and/or silver. After consideration of the data on available alloys, the particular combination of Sn3.9Ag0.6Cu was chosen as it could be readily supplied by four different solder manufacturers.
``The NEMI Lead Free Assembly Project is solving a critical industry wide problem,' according to Dr. David Lando, chairman of the NEMI Board of Directors and Engineering & Environmental Technologies Vice President for Lucent Technologies. ``The project is providing solutions that can be readily implemented, are cost effective, and are available in the marketplace. We will seek cooperation with groups in other regions of the world in order to help ensure that these solutions become routinely deployed on a worldwide basis.'
Use of the recommended alloys will raise the melting point by as much as forty degrees, which obviously has an impact on a number of the materials and steps in the assembly process, and affects companies throughout the supply chain. The NEMI Lead-Free Assembly Project is also working to identify the impacts that eliminating lead will have on the manufacturing infrastructure and will work closely with component, board and equipment manufacturers to provide a smooth transition of manufacturing processes for member companies wishing to implement lead-free solders.
About NEMI
The National Electronics Manufacturing Initiative was formed in November 1994 to facilitate long-term North American leadership in electronics. The industry-led consortium is made up of over 50 electronics equipment manufacturers, suppliers, associations, government agencies and universities, representing a combined total of more than $200 billion in revenues (1998) and more than 1.25 million employees.
NEMI roadmaps the needs of the North American electronics industry, identifies gaps in the technology infrastructure, establishes implementation projects to eliminate these gaps, and stimulates standards activities to speed the introduction of new technologies.
Press information: Project information:
Cynthia Williams Ron Gedney
Edelman/GTT NEMI
cwilliams@mindspring.com rgedney@nemi.org
207-871-1260 703-834-2084
SOURCE: National Electronics Manufacturing Initiative
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