SMT007 Magazine


Issue link:

Contents of this Issue


Page 91 of 115

92 SMT Magazine • January 2017 The tin whisker phenomenon is an issue that has plagued the electronics industry for many years now; however, with even more sectors of the industry now looking to shift or go lead- free—eliminating or limiting lead—in their pro- cesses and products, focus on this potentially devastating issue appears to be on the rise once again. A topic that was a huge concern with- in the industry a decade or so ago, appeared to have waned in recent years, only to be re-estab- lishing itself again from where I sit in the inde- pendent test laboratory world. The phenomenon itself has been studied by many for years now and the question—why do whiskers form—has many answers and theo- ries. In this column, I'm not focusing on the hows and whys of whisker formation, which can be an exhaustive discussion, but more so the testing side of things—more specifical - ly, the testing that has been established to test your mitigation strategy or strategies. To that point, there is no single, perfect strategy for preventing tin whisker formation—other than putting lead in it, which kind of defeats the purpose I suppose—so don't assume that one strategy fixes everything. For background, mit - igation practices include all sorts of strategies, from heat treatments/annealing to conformal coatings/potting to matte versus bright tin fin- ishes to many others. As you may already know or have heard about, trying to control, influence, or predict the growth of tin whiskers is difficult to accom- plish. With that, testing of your mitigation prac- tices is critical and prudent for those truly doing their due diligence in the development of a re- liable product. Various passages on tin whisker mitigation strategies can be found in industry magazines, scholarly journals, reference books, etc., so be sure to do a little research before you get too deep. As discussed in my October 2016 column, experience is everywhere and you can learn a lot of dos and don'ts by just doing a lit- tle homework. An easy place to start when it comes to the testing of whichever mitigation strategy or strategies that you've implemented is a group of documents that are well-established in the tin whisker testing world. Specifically, the Joint Electron Device Engineering Council (JEDEC) has established two test standards that are very commonly used for tin whisker testing or are by Keith M. Sellers NTS-BALTIMORE Got Whiskers? LET'S TALK TESTING Figure 1: Trying to control, influence, or predict the growth of tin whiskers is difficult to accomplish.

Articles in this issue

Links on this page

Archives of this issue

view archives of SMT007 Magazine - SMT-Jan2017