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NPL is internationally recognised for its practical and innovative work on lead-free reliability, PCB interconnection failures, tin whisker migration and conformal coating research. These FREE online webinars provide the opportunity to draw on years of practical experience without leaving your desk. To participate, you need a phone line and Internet access. Please note that registration is essential.
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A New Draft Standard for Condensation Testing Martin Wickham/Ling Zou
17th March 2020
2:30 PM - 4:00 PM GMT
Achieving high reliability in service is the key issue in today’s high-density electronics assemblies. Electrochemical reliability becomes more critical, as electronic circuits move to increased packaging densities, and are operated in harsher environments (hotter/damper/condensing). Contaminants and bias with moisture facilitate electrochemical corrosion processes that result in a loss of continuity or short circuit (failures) on electronic assemblies. Moisture plays an important role for circuit failure, and condensation will accelerate the failures.
The electronics industry uses a number of condensation tests developed by large OEMs. They all differ and it is challenging and costly for materials suppliers to test multiple materials across all condensation tests. Additionally, most of these standards are based on changing the environment around the test vehicle to create condensation and are therefore highly dependent on the thermal mass of the test vehicle and capability of the chamber being utilised.
NPL has been working with industrial partners on a collaborative project to develop a new approach to create controllable condensation on test vehicles. The temperature of the test vehicles can be directly depressed to any required level without disturbing the stable environmental condition. Different levels of condensation can be cycled to simulate condensation real world scenarios. Results will be presented based on a test assembly with a range of fine pitch components including QFNs, QFPs and chip capacitors. In a 48 hour SIR test, coated assemblies with different coating variables, were subjected to eight increasing levels of condensation from low to high. The condensation level where SIR values dropped below 100 MΩ can be used to score the protection performance of different combinations of coatings, application processes and components. A draft standard is now in preparation and an outline of the new standard will be given for industry comment.