Thomas M. Forsythe
Nashville, TN, USA
As electronic assemblies have grown ever more capable over recent years, their form factors had decreased at an impressive rate of their won. These small gaps and design challenges have emerged in concert with a renewed requirement for entire assembly cleaning driven by an array of requirements led by increasing reliability requirements. Of course, while cleaning has always been mission critical for a number of segments, such as medical and military assemblies, today it is being adopted broadly throughout the industry.
This presents both advanced technology groups and manufacturing engineers with a new process to implement with little tribal knowledge within their organization to base their evaluation on. This paper will study these small gaps and evaluate ionic residues post cleaning by a variety of cleaning agents versus a pair of commonly encountered water soluble fluxing materials. This will allow users to understand the challenges presented by low gap height and the risks associated with various cleaning approaches to remove those residues.
With the control data skewed, Agent C breaks out as the winner though temperature and concentration do not trend toward more is better. The large data package in this DOE makes the analysis rather straight forward. As in most protocols, where are ambiguous results at times and not every dataset reaches the same conclusion. This point is key; any particular product life cycle may have unique sensitivities important to its operating for everyday of its service life. Detailed data such as this, though expensive and time consuming to generate can be enormously instructive for such high value, long lived devices.
Initially Published in the SMTA Proceedings