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

• Published in: Soldering & surface mount technology Vol. 20; no. 3; pp. 18 - 25
• Main Authors: Huang, Meng-Kuang, Lee, Chiapyng
• Format: Journal Article
• Language: English
• Published: Bradford Emerald Group Publishing Limited 01.01.2008; Emerald
• Subjects: Alloys; Applied sciences; Design. Technologies. Operation analysis. Testing; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Electronics industry; Exact sciences and technology; Integrated circuits; Lifetime; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Temperature; Testing, measurement, noise and reliability; Thermal cycling; Lead; Solders; Failure modes and effects analysis; Thermal stress; Thermal cycle; Printed circuit board; Solder metal; Solderability; Failures; BGA technology; Chip scale packaging; Flat package; Integrated circuit bonding; Solder bump; Integrated circuit testing; Electronic packaging; Soldered joint; Testing equipment; Lead free soldering; Printed circuit; Reliability; Electroless plating; Comparative study; Small outline
• ISSN: 0954-0911; 1758-6836
• DOI: 10.1108/09540910810885688

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.