Editorial

摘要

The evolution of the printed circuit board has long been characterised by the demand for greater interconnect density and smaller size. This has seen the once humble PCB evolve into a highly sophisticated interconnect platform that would have seemed impossible 30 years ago. This evolution has been made possible by the development of new processes, equipment and materials. It is also notable that such progress has been achieved whilst not only maintaining and enhancing reliability but also doing so while accommodating, in many cases, the mandated move to lead-free assembly. This issue of Circuit World begins with a paper reporting a new approach for investigating circuit board reliability based on local damage simulations. While there has been much work and data reported on solder ball related reliability, the research detailed in this paper has a focus on the connection between the solder ball and the underlying copper pad on the board. For this work, the focus was on the effect of dynamic loads, such as those occurring when a device is dropped. There are already well established industry standard procedures for testing reliability under drop impacts and these have been shown to be capable of delivering reliable results. However, in this study an approach based on a so-called board level cyclic bend test (BLCBT) was adopted as an alternative.