In electronics equipment, tin-lead solder has been widely used to solder integrated circuits (ICs) as well as other electronic components on printed wiring boards (PWBs) and also to make electrical connections among electronic components. However, in recent years, due to environmental concerns, the electronics industry has been migrating to lead-free solders.
A tin plated terminal might be subject to the growth of tin whiskers, which could cause shorts in electric circuits. Whiskers, when they form, tend to grow with time through the re-crystallization of tin into long, usually single crystal, filaments which can actually bridge two terminals. This is of particular concern where product reliability and extended life are important. But not every product lot (or plating bath) grows whiskers. Since the basic mechanism for growth is not understood, the industry does not know how to consistently avoid them. It is important that a test method be developed for predicting the susceptibility of electronic component terminals to the growth of tin whiskers, and the same test methodology is accepted worldwide.
On May 15, Soldertec, NEMI and JEITA held the Tin Whisker Joint Meeting to update the status of the current programs and exchange data crucial to the selection of key test parameters. Representatives in the photo are (left to right): Ichizo Sakamoto, JEITA; Irina Boguslavsky, NEMI; and Nick Hoo, SOLDERTEC.
All three project teams agree that more work must be done to establish the exact test protocol. However, the following test conditions have been agreed to, and identified as the basis for a full protocol of whisker test conditions:
High temperature/humidity condition test
Thermal cycling (TC)
For the high temperature: 85degC
For the low temperature: �40degC or �55degC
For the dwell time, heating and cooling rates: to be determined
For the room temperature: 20 to 25 degC, or 15 to 35 degC, to be determined
Other specific conditions, if necessary, shall be identified
Additional work is planned in all three projects to obtain a better understanding of factors affecting whisker growth. Based on this information, a joint proposal for a standardized whisker test protocol will be submitted by 2004. The three parties recognized that the tin whisker test method is important for implementation of lead-free technology. They also agreed to continue the information exchange on tin whiskers.
After the conference ended, each group held meetings to confirm this joint press release. As a result, this press release was confirmed and announced today.
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For further information, please contact the following organizations:
National Electronics Manufacturing Initiative, Inc. (NEMI)
Cynthia Williams, Director of Communications
SOLDERTEC at Tin Technology Ltd.
Tel: +44 (0)870 458 4242
Japan Electronics and Information Technology Industries Association (JEITA)