Soldering & Surface Mount Technology
16/2 [2004] 9
Emerald Group Publishing Limited
[ISSN 0954 0911]

Surface mount technology (SMT) has become the main technique for the board level assembly of microelectronic devices since 1980s. For surface mounted components (SMCs), the solder joints not only provide for the passage of electrical signal and power, but also the mechanical support to hold the package in position on the printed circuit board (PCB). Since the dimensions of solder joints are relatively small and the electronic devices may experience thermal-mechanical loadings during operation, the solder joint reliability of SMCs is a major concern in the electronics manufacturing industry.

This special issue of SSMT is a collection of seven papers on the subject of solder joint reliability. All of the papers were subject to a process of peer review and revision.

The first paper gives a comprehensive discussion on the long-term reliability of lead-free solders. This paper considers the transition in terms of performance, with particular emphasis on long-term, high reliability applications. Comparison of key mechanical properties indicated generally beneficial outcomes of the transition to lead-free alloys, although there might be a lack of understanding surrounding anomalous observations. Sole reliance upon empirical testing has become non-viable, and there is an urgent need for a greater understanding of solder behaviour to act as a basis for phenomenological methods of life prediction and design.

The second paper presents an experimental study to assess the reliability of solder ball attachment to the bond pads of a plastic...