The effect of solder paste composition on the reliability of SnAgCu joints

✍ Scribed by S. Nurmi; J. Sundelin; E. Ristolainen; T. Lepistö

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 565 KB
• Volume: 44
• Category: Article
• ISSN: 0026-2714
• DOI: 10.1016/j.microrel.2003.08.004

✦ Synopsis

As the electronics industry is moving towards lead-free manufacturing processes, more effort has been put into the reliability study of lead-free solder materials. Various tin-silver-copper-based solders have become widely accepted alternatives for tin-lead solders. In this study, we have tested three different SnAgCu solder compositions. The first consisted of a hypoeutectic 96.5Sn/3.0Ag/0.5Cu solder, the second of a eutectic 95.5Sn/3.8Ag/0.7Cu solder, and the third of a hypereutectic 95.5Sn/4.0Ag/0.5Cu solder. A eutectic SnPb solder was used as a reference. The test boards were temperature-cycled ()40 to +125 °C) until all samples failed. The results of the temperature cycling test were analyzed, and cross-section samples were made of the failed joints. Scanning electron and optical microscopy were employed to analyze the fracture behavior and microstructures of the solder joints. The reliability of lead-free solders and the effect of microstructures on joint reliability are discussed.