The National Electronics Manufacturing Initiative (NEMI, Herndon, VA) has issued a set of interim recommendations for lead-free component finishes to be used in high-reliability electronic applications to minimize the risk of failures caused by tin whiskers. These recommendations were developed by the consortium's Tin Whisker User Group, comprised of nine large manufacturers of high-reliability electronic assemblies that annually purchase millions of dollars of components.

The group was organized to define methods and tests that would minimize the probability of tin whiskers creating functional or reliability problems in their products. Members include Alcatel, Celestica, Cisco Systems, Delphi Electronics, HP, IBM, Lucent Technologies, Sun Microsystems and Tyco Electronics. The group consensus is that pure tin electroplating presents a risk in high-reliability applications, and they have outlined cost-effective alternatives—using known mitigation practices and some level of testing—to minimize this risk.

This second interim report updates a report published by the group in June 2003 and presents recommendations for lead-free finishes for a variety of applications. These recommendations reflect the best judgment of the group members, based on their own experiences and the available data. The document outlines specific whisker mitigation guidelines supported by the group.

The document also discusses specific component types, assessing the reliability risk of tin whiskers for each and the various mitigation strategies recommended. The group is currently in the process of extending this work to create a user acceptance specification based on the test methods defined by the NEMI Tin Whisker Accelerated Test Project.

The Tin Whisker User Group's recommendations are available at: http://www.nemi.org/projects/ese/tin_whisker_usergroup.html.

Copyright 2004, UP Media Group. All rights reserved.

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