Issue link: https://iconnect007.uberflip.com/i/1002143
10 PCB007 MAGAZINE I JULY 2018 As you can see, there are many areas and much to learn and think about with solder masks, but let's move on to our columnists. This month, Mike Carano, RBP Chemical Tech- nology, discusses flexible metalization, specifi- cally possible problems associated with adhe- sion of electroless copper to both substrate and copper layers. Needless to say, the process is significantly different from that used for FR-4 and other common substrate materials. Bringing up the rear is IPC's John Mitchell and his column about automotive electron- ics. After reviewing some of the major chang- es that have occurred in the past few years, he discusses the automotive addendums that are under development through IPC and asks for your input and expertise to help with that. Well, it's July and 2018 is already half gone. As always, we ask, how did that happen? But of course, we are not nearly done with provid- ing interesting and informative coverage on a wide range of topics in the upcoming issues. Next month the topic is reliability and then we plan to focus on mSAP and SLP in September. I sure hope you are a subscriber by now! PCB007 Patricia Goldman is managing editor of PCB007 Magazine. To contact Goldman, click here. et al., is the effect of a solder mask and its resi- dues on the subsequent final finish process. The focus here is on identifying possible markers that could be detrimental to both the final fin- ish chemistry and the solderability of the board during assembly. While it was good to talk with the chemistry people, we wanted to hear from the equipment folks, too. Circuit Automation has been mak- ing automated screen printing equipment for a very long time, so we tapped Tom Meeker, Lar- ry Lindland and Yuki Kojima. As is often the case, we ended up learning about much more than just screen-printing equipment, including how different formulations require different set-up parameters, the difficulty of plugging a variety of hole sizes on one board, the impor- tance of a uniform coating, handling flex—and the list goes on. Lackwerke Peters' Sven Kramer wrote a great article on the thermal capabilities of sol- der masks. Not only must they survive high- temperature solders and rather aggressive final finishes, but they are then exposed to consid- erable thermal stress and high humidity con- ditions in the field—think automotive applica- tions—all while reliability demands have be- come more stringent. Kramer presents a prim- er on solder mask formulation, aging test data with illustrations, and then a fine discussion on white LPI solder masks. A Rutgers-led team of physicists has demonstrated a way to conduct electricity between transistors without energy loss, allowing low-power electronics and, potentially, quantum com- puting that would be far faster than today's computers. Their findings, which involved using a special mix of materi- als with magnetic and insulator properties, are published online in Nature Physics. "This material, although it's much diluted in terms of magnet- ic properties, can still behave like a magnet and conducts elec- tricity at low temperature without energy loss," said Weida Wu, senior author of the study and associate professor in the De- partment of Physics and Astronomy at Rutgers University–New Brunswick. Rutgers-led Research Could Lead to More Efficient Electronics