This app note discusses the problems caused by the removal of lead from electronics and ways to mitigate tin whiskers:
“Tin whiskers” is not an imaginative, fanciful term for some aspect of electronics manufacturing. Tin whiskers are real. They are microscopic conductive fibers emanating from pure tin surfaces, and they pose a serious problem to electronics of all types. These whiskers can form electrical paths, which affect the operation of the subject device. This article discusses the problems caused by the removal of lead from electronics and describes some techniques to mitigate tin whiskers.
A similar version of this article appeared in the November 15, 2011 issue of EE Times magazine.