Editorial

Citation

Goosey, M. (2012), "Editorial", Soldering & Surface Mount Technology, Vol. 24 No. 1. https://doi.org/10.1108/ssmt.2012.21924aaa.001

Editorial

Article Type: Editorial From: Soldering & Surface Mount Technology, Volume 24, Issue 1

Despite the huge amount of work already undertaken and reported on the development of lead-free solders, the demand for new alloys and processes that can provide viable alternatives to conventional tin-lead solders continues unabated. One area that has received much attention in recent years has been the modification of existing alloys by the addition of small quantities of metals or other materials. In the first paper of this issue of Soldering & Surface Mount Technology, Krystyna Bukat, Janusz Sitek, Marek Koscielski, Zbigniew Moser, Wladyslaw Gasior and Janusz Pstrus report the results of their continuing work on tin-zinc-bismuth alloys and, in particular, they give details of an investigation into the influence of indium additions on alloy wetting properties on PCBs with lead-free HASL and immersion tin solderable finishes.

Each of the next three papers covers a specific aspect related to reliability and testing. In the first of these, the performance of conformal coatings is addressed. Conformal coatings play a very important role in many electronic assemblies and are often critical in helping to deliver long-term reliability, especially in less benign operating environments. In the paper by Ling Zou and Chris Hunt from NPL, a new test method for evaluating the adhesion of conformal coatings to electronic assemblies is described. This new method should be of benefit to coating developers, as well as to users, and it provides a tool that can used to minimise adhesion failures in service.

The performance of solder joints at low temperatures can be a significant concern for both manufacturers and users of equipment required to operate reliably in harsh environments and these concerns have become increasingly important with the move away from lead-containing solders to tin-based and lead-free alloys. In the paper by De-Shin Liu, Chang-Lin Hsu, Chia-Yuan Kuo, Ya-Ling Huang, Kwang-Lung Lin and Geng-Shin Shen, details of a high-speed impact-testing method for evaluating the effects of low temperatures on eutectic and lead-free solder joints are reported. In an effort to overcome the issues experienced with related approaches, the authors present information that specifically focuses on cryo-impact testing systems and the experimental steps required to improve the accuracy of post-testing analysis.

The fourth paper of this issue is by Ryan S.H. Yang, Derek R. Braden, Guang-Ming Zhang and David M. Harvey and it covers the through lifetime monitoring of solder joints using acoustic micro imaging (AMI). The authors detail an evaluation of the application of the AMI inspection technique for monitoring solder joint performance. They also demonstrate the robustness of the monitoring through analysis of the AMI data; also a strong agreement was observed between the AMI test data and predictions from finite element analysis. The use of the AMI inspection approach was found to enable the through lifetime non-destructive monitoring of solder joints in real-life conditions.

Finally, this issue concludes with an extensive and comprehensive review of one of the key basic processes utilised in modern electronics assembly. The use of stencils and stencil printing provides a low-cost and high-throughput method for creating mechanical and electrically conductive connections between substrates, bare die, packaged chips and discrete components. The paper by Robert Kay and Marc Desmulliez from Heriot-Watt University gives an extensive review of the different stencil technologies and printing materials that are currently in use. It also discusses the various factors that determine the outcome of a successful printing process, including printing parameters, materials, apparatus and squeegees. The authors also provide information on relevant technical innovations in the art of stencil printing for microelectronics packaging.

It is only rarely that this journal receives detailed review papers such as the one mentioned above and included in this issue. These reviews are often very valuable to both academic researchers and those working in industry and I would therefore like to offer an open invitation to readers to submit more review articles for publication. I do hope that you find these papers, and the rest of the contents in this issue, both interesting and useful. The journal is always seeking to increase its team of paper reviewers and I would be pleased to hear from those with an interest in reviewing the latest novel research that is submitted for publication. I would also like to remind authors that the paper submission process for this journal is via an online system called “ScholarOne Manuscripts”. Finally, I am pleased to receive feedback and comments from subscribers and can be contacted by e-mail at: m.goosey@lboro.ac.uk

Martin Goosey