Lead-Free Assembly Project (completed)

iNEMI's 1998 Roadmap identified the need for materials and processes that would allow manufacturers to eliminate lead (Pb) from electronic assemblies.  The roadmap warned that, to remain competitive in the global marketplace, electronics manufacturers would need to develop the capabilities, processes and technologies required to produce Pb-free assemblies.

In 1999, iNEMI organized the Lead-Free Assembly Project with the goal of developing manufacturing capability to produce Pb-free products.  By early 2000, the project team recommended an industry-standard alloy -- Sn3.9Ag0.6Cu -- to replace tin-lead solders for reflow.  Their recommendation was based on availability, patent considerations and backward-compatibility issues.  Today, a narrow range of compositions in the SnAgCu system is the most widely recommended as a general purpose, standard alloy for surface mount, wave and hand soldering in a variety of product types.

After recommending an alloy, the project team conducted extensive testing to characterize the new materials and demonstrate reliability.  Project accomplishments include:

• Definition of modeling and data needs for Pb-free solders
• Physical and mechanical properties database compiled in conjunction with NIST (available online at http://www.metallurgy.nist.gov/solder/)
• Extensive reliability testing

Several iNEMI members are using the alloy in production.  By focusing on a single Pb-free alloy, iNEMI helped industry accelerate convergence on standard solder formulations, manufacturing processes and, ultimately, the timely and cost-effective conversion to Pb-free assembly.  This project, which was completed in late 2003, moved the industry forward in knowledge and understanding of Pb-free materials and processes.

FINAL REPORT (December 2003)

Press releases

Articles

Presentations

Additional information

Other lead-free topics

Press Releases

IPC and NEMI Sponsor Symposium on Lead-Free Electronics September 18-19 in Montreal (7.23.02)

NEMI's Lead-Free Assembly Project Reports Latest Results at APEX 2002 (1.21.02)

Modeling and Data Needs of Lead-Free Solders is Focus of Upcoming Workshop (01.29.01)

NEMI's Lead-Free Project Builds Momentum (08.29.00)

NEMI and ITRI Collaborate to Investigate Issues Relating to Effects of Lead-Free Solder on the Manufacture of PWBs (04.03.00)

Group Recommends Tin/Silver/Copper Alloy as Industry Standard for Lead-Free Solder Reflow in Board Assemblies (01.24.00 NEMI)

NEMI Kicks Off New Lead-Free Assembly Project at IPC's "Get the Lead Out" Conference (10.26.99)

NEMI Kicks Off New Lead-Free Assembly Project and Sponsors Industry Forum on Same Topic at IPCWorks� Conference (08.10.99)

NEMI Forms "Lead-Free Readiness" Task Force (05.03.99)

Articles

NEMI's Lead-Free Alloy: Still on Target, Alan Rae, Cookson Electronics, and Carol Handwerker, NIST, Circuits Assembly, April 2004 (cover article), pp. 20-25.

Lead-free Solder Assembly: Impact and Opportunity, Edwin Bradley, Motorola, Electronic Components and Technology Conference (ECTC), May 27-30, 2003 (New Orleans, LA).

"A Manufacturable Lead-Free Surface-Mount Process?" by Jasbir Bath, Circuits Assembly, January 2003, pp. 26-29.

"NEMI Report: A Single Lead-Free Alloy is Recommended," Edwin Bradley, Motorola; Carol Handwerker, NIST; and John E. Sohn, cover story, SMT, January 2003.

"Environmental Work Goes On," Edwin Bradley, Motorola, Electronic News, January 21, 2002, p.20.

"Characterization of the Melting and Wetting of Sn-Ag-X Solders," by Edwin Bradley III, Motorola, and Jasmina Hranisavljevic, Argonne National Laboratory, IEEE Transactions on Electronics Packaging Manufacturing, Vol., 24, No. 4, October 2001.

"Are Lead-Free Solder Joints Reliable?" John E. Sohn, Ph.D., Circuits Assembly, June 2002, p. 31.

"Database on Lead-Free Solders," T.A. Siewert, D.R. Smith, S. Liu, and J.C.Maden, Proceedings of the Electronic Components and Technology Conference, 2001.

"The Next No-Lead Hurdle: the Components Supply Chain," Richard Parker, CircuiTree, August 2000.

"Research Update: Lead-Free Solder Alternatives," Jasbir Bath, Carol Handwerker and Edwin Bradley, Circuits Assembly, May 2000.

"Lead-Free Project Focuses on Electronics Assemblies," Edwin Bradley, Jasbir Bath, Gordon Whitten and Srinivas Chada, Advanced Packaging, February 2000.

"Lead-Free Update: Industry-Based Effort Pushes for Lead-Free Assemblies," Edwin Bradley, Ken Snowdon, Ronald Gedney, Circuits Assembly, December 1999.

Presentations

NIST Pb-Free Solder Projects: Progress and Results, Carol Handwerker, NIST, IPC/JEDEC 4th International Conference on Lead-Free Electronic Components & Assemblies, October 21-22, 2003 (Frankfurt, Germany).

NEMI Pb-Free Solder Project, presented by Carol Handwerker (NIST), September 25, 2003, SMTA International conference (Chicago, IL).

APEX 2002 (January 23, 2002)

    "Background & Overview of Lead-Free Project," Edwin Bradley, Motorola
    "Lead-Free Alloy Group Status," Carol Handwerker, NIST
    "Lead-Free Component Team Status," Rich Parker, Delphi Electronics
    "Lead-Free Process Group Status," Jasbir Bath, Solectron Corporation
    "Lead-Free Reliability Team Status," John Sohn, NEMI consultant


Workshop on Modeling and Data Needs for Lead-Free Solders, February 15, 2001 (New Orleans, LA)

APEX 2001

    "Introduction," Edwin Bradley (project leader), Motorola (120K PDF)
    "Pb-Free Database," Carol Handwerker, NIST (235K PDF)
    "Soldering Process," Jasbir Bath, Solectron (1.3MB PDF)
    Agilent 5DX Images (960K PDF)
    "Solder Joint Reliability," John Sohn, Lucent (450K PDF)
    "Component Overview," Rich Parker, Delphi Electronics (185K PDF)
    "Wave Soldering with Lead-Free Alloys," Denis Barbini, Vitronics-Soltec (325K PDF)
    "Q&A," Elizabeth Benedetto, Compaq (28K PDF)


Lead-Free Project Status Report (presentation), September 2000. (744K PDF)

"Lead-Free Assembly Drivers," Edwin Bradley, Motorola, at IPCWorks, October 1999

"Alternative Metallic Finishes for PWB," Bruce Houghton, Celestica, paper presentated at IPC Expo 1997 (1MB PDF)

Additional Information

Materials for Microelectronics: Solder and Solderability Measurements for Microelectronics (NIST)

"Roadmap of Lead-Free Assembly in North America," JISSO/PROTEC Forum 2002, November 19-20, 2002; Japan. (paper and presentation)

"Towards a Green 2000" (a whitepaper discussion of the WEEE Directive in Europe), Ken Snowden, Nortel Networks. (72K PDF)

"Compatibility of Lead-Free Solders and Surface Finishes," Alan Rae, Gene Smelik and Jim McLenaghan, Cookson Electronics Process Development Group (9.20.00) (812K PDF)

"Reflow Profile for Test," Richard D. Parker, Delphi Electronics (10.12.99)

"Microelectronics: Rising to the Environmental Challenge!?" Harry K. Charles, Johns Hopkins, and Nihal Sinnadurai, TWI (145K Adobe Acrobat file)

"Environment and Electronics: Theory and Practice," Kirsten Stentoft, Danfoss Drives A/S (70K Adobe Acrobat file)

Where the lead comes from in a typical solder joint (image)