NPL/SMART Group Conformal Coating & Cleaning Experience
Minor de-wetting or bubbles on non-critical areas such as substrate or package surfaces should not be a reason for rejection, but the occurrence of such defects between terminations could have a serious impact on reliability if potentially corrosive materials were not fully encapsulated. Electrochemical reliability problems were caused either by simple metallic corrosion of solder, PCB conductor or component termination by contaminants from PCB production processes, flux residues or harsh environments, or by electrochemical effects in the presence of bias voltage. The most important failures of this type were dendrite formation and conductive anodic filamentation (CAF) and Willis showed several examples from the NPL Process Defect Database.
The NPL/SMART Group Conformal Coating & Cleaning Experience delivered a wealth of free practical help and advice to engineers wishing to gain an appreciation of the realities of coating, cleaning, and testing techniques and guidance on material selection to suit particular service conditions. Seven delegates diligently attended every single session, and were additionally rewarded for their attendance with packs of IPC standards, presented by organiser Bob Willis.
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