Board level reliability of lead-free designs of BGAs, CSPs, QFPs and TSOPs

Meng-Kuang Huang; Chiapyng Lee

doi:10.1108/09540910810885688

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Soldering & Surface Mount Technology

ISSN: 0954-0911

Online from: 1989

Subject Area: Electrical & Electronic Engineering

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Board level reliability of lead-free designs of BGAs, CSPs, QFPs and TSOPs

Document Information:
Title:	Board level reliability of lead-free designs of BGAs, CSPs, QFPs and TSOPs
Author(s):	Meng-Kuang Huang, (Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan), Chiapyng Lee, (Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan)
Citation:	Meng-Kuang Huang, Chiapyng Lee, (2008) "Board level reliability of lead-free designs of BGAs, CSPs, QFPs and TSOPs", Soldering & Surface Mount Technology, Vol. 20 Iss: 3, pp.18 - 25
Keywords:	Failure modes and effects analysis, Lead, Solders
Article type:	Research paper
DOI:	10.1108/09540910810885688 (Permanent URL)
Publisher:	Emerald Group Publishing Limited
Acknowledgements:	The authors acknowledge the assistance of Dr Yee-Wen Yen, Dr Pei-Lin Wu and Dr Shyh-Rong Tzan, who contributed their precious time to conduct some of the experiment works.
Abstract:	Purpose – The purpose of this paper is to describe the board level reliability test results of four IC packages with lead-free balls/platings, soldered with lead-free solder paste, during thermal cycling. The board level reliability test results of tin-lead balled/plated packages soldered with lead-free solder paste have also been included for comparison. Design/methodology/approach – Four different packages, i.e. ball grid array (BGA), chip scale package (CSP), quad flat package (QFP) and thin small outline package (TSOP), were assembled on a test printed circuit board (PCB) as the test vehicle. Lead-free and tin-lead BGA/CSP packages were equipped with Sn-3.0Ag-0.5Cu and Sn-37Pb solder balls, respectively. The lead-frames of lead-free QFP/TSOP leaded-packages were plated with Sn-58Bi and those of tin-lead QFP/TSOP leaded-packages, Sn-37Pb. The lead-free solder paste used in this study was Sn-3.0Ag-0.5Cu. Two kinds of surface finishes, immersion gold over electroless nickel (Au/Ni) and organic solderability preservative, were used on the PCBs. The test PCBs were thermal cycled 5,000 times within the temperature range of -40 to 125°C and electrically monitored during the thermal cycling. Findings – It was found that the tin-lead balled/plated BGAs, CSPs, QFPs and TSOPs soldered with lead-free solder paste showed serious board level reliability risks as their abilities to withstand thermal cycling stresses are much weaker than those of entirely lead-free assemblies. Neither package nor surface finish was found to have any effects on the board level reliability of test vehicles with lead-free balled/plated BGAs, CSPs, QFPs and TSOPs. Metallographic examinations were conducted to investigate the effect of thermal cycling on the failure modes of solder joints. Originality/value – The paper is of value by contributing to research in the use of lead-free solder paste with lead-containing packages in the industry. Currently, there is a deficiency of knowledge in this area.