Development Of A Test Vehicle For The Study Of Tin Whiskers
Authors: Heather McCormick, Jimmy Chow, Polina Snugovsky, Eva Kosiba, and Stephan Meschter Company: Celestica Inc. and BAE Systems Date Published: 5/4/2011
ICSR (Soldering and Reliability)
Abstract: As the electronics manufacturing industry transitions to lead free, tin whiskers become a significant concern once again. The formation of tin whiskers poses a risk to reliability, as they can cause shorts if they become long enough or break off and create bridges across finely spaced features. While the use of lead in solders and leadframe platings enabled tin whiskers to be controlled in tin/lead assemblies, this is no longer an option once products must transition to lead free. This paper summarizes the development of a test vehicle that will be used in a study to determine which factors affect the growth of tin whiskers, and the effectiveness of potential mitigation strategies. The test vehicle focuses studying the role of various process and assembly related factors play in the growth of tin whiskers, such as the use of different leadframe materials, different solder alloys, and the effect of ionic contaminations. Details of the various features of the test vehicle are outlined, and in each case, the reasons for including them will be explained.
The test plan for the project where the test vehicle will first be used is outlined, however, there is potential to re-use the test vehicle for future studies in different use environments and with other assembly variations.