SMTA International Conference Proceedings


Authors: Heather McCormick, Alex Chan, Richard Coyle, Donald Harper, Steve Minich, Damir Jelkovic, Brent Peterman, and Mark Gray
Company: Celestica Inc., 4FCI, and Alcatel-Lucent
Date Published: 10/11/2007   Conference: SMTA International

Abstract: Though there is a growing database of reliability test results for array connectors, the majority of these results have been generated using tin/lead versions of the connectors. However, as some products which make use of area array connectors, such as server and telecommunication products, are transitioned to lead free ahead of the 2010 deadline imposed by the European Union’s RoHS legislation, there is a need to generate reliability data on lead free versions of the connectors. The “Metro2” test vehicle includes two types of lead free area array mezzanine connectors, and two versions of lead free area array backplane connectors. The test vehicle will by subjected to 6000 cycles of acceleratedthermal cycling from 0°C to 100°C in accordance with IPC-9701A. As both mezzanine connectors were previously included on the original “Metro” test vehicle which underwent the same thermal cycling conditions, the results of the lead free testing can be compared with the results on tin/lead versions of the same connectors.

In addition to assessing the reliability of the lead free area array connectors generally, additional testing on one of the mezzanine connectors focuses on determining the impact of changes to the test vehicle design on the connector’s reliability and failure locations. Results from the “Metro” test vehicle indicated that test vehicle design parameters may impact the reliability and/or failure mode of the mezzanine connectors. As a result, some of the testing on “Metro2” will focus on assessing the impact of changing the total stack height of the connector from 4 mm to 14 mm on the reliability of the connector, and also the impact of changing the thickness of the daughtercard from 0.062” to 0.093”. This data will assist in developing recommendations for area array test vehicle designs in an effort to standardize the reliability testing of area array mezzanine connectors.

Key words: BGA Connectors, Lead Free Assembly, Reliability

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