Conformal Coatings And Their Impact On QFN Reliability
Authors: C Yin, S Stoyanov, C Bailey and P Stewart, S McCallum Company: University of Greenwich and Leonardo MW Ltd Date Published: 2/6/2017
Pan Pacific Symposium
Abstract: For high reliability applications, the use of QFN’s are receiving increased interest. To address concerns such as tinwhiskers and harsh environmental conditions, conformal coatings are used. But there is a lack of data on how these conformal coatings can impact subsequent reliability of these low stand-off height components. This paper details an investigation into the impact of conformal coatings on the reliability of second-level interconnections in QFNs. Five QFN package types (including plastic and ceramic QFNs) and two types of conformal coatings have been investigated. It is concluded that conformal coatings can have a significant impact on the reliability of solder joints in QFNs. This level of impact is dependent on the package size and the conformal coating properties. It was also found that increasing the solder stand-off height will reduce solder damage and hence improve solder reliability.