Issue link: https://iconnect007.uberflip.com/i/1010078
12 SMT007 MAGAZINE I AUGUST 2018 Eric Camden: The critical points for cleaning these days are the bottom-terminated components in general, but with a focus on QFNs because of their low standoff height— which are very difficult to process either with water-soluble or no-clean flux. If you are trying to clean a no-clean flux from underneath a QFN, you are going to struggle, there's no doubt about it. And I am talking about the best cleaning equipment that you can find. You still need to have a fine eye and be able to tune your cleaning process to address the QFNs. And if you can do that in general, you can say that other components will be very clean because you can effectively clean the hardest part on the board. So, from a failure analysis point, from a process reliability standpoint, from what we do in the analytical world, we see lots of issues in QFN during a wash process. It's very difficult to outgas the flux activators when you are starting at half a mil or 1 mil Feature by the I-Connect007 Editorial Team The continuing growth of the electronics industry, driven by the rapid expansion of electronics into areas such as automotive and medical, is creating a new mindset with regard to cleaning, mainly due to quality and reliability issues. Historically considered a non-value- add, cleaning is now being increasingly relied upon by manufacturers to mitigate potential board defects. For this month's issue of SMT007 Magazine, we invited failure analysis experts Eric Camden and Paco Solis, both lead investigators at Foresite Inc., and industry veteran Greg Smith, manager of stencil technology at BlueRing Stencils, to share their experiences with cleaning challenges in PCBAs and possible solutions. Stephen Las Marias: What are the most critical challenges when it comes to cleaning?