Issue link: https://iconnect007.uberflip.com/i/1067105
62 SMT007 MAGAZINE I JANUARY 2019 Stevenson: Yes, even using classic FR-4, which can be done, they still have to control those line widths and impedance. Matties: It's certainly significant enough for you to invest quite a bit of money on the tech- nology. Stevenson: Yes. When we started this project, an engineer involved said, "We just need to implement a quick testing solution." We did some further research and determined if we're going to do impedance, we have to go all the way in. We have to have the upfront model- ing and feedback from our manufacturing floor on press thicknesses of dielectrics and line width tolerances, shapes, and TDR values, and we need to etch to impedance. We no longer expect engineers to model to the tolerances and hope the impedance is going to come out at the end. We need to be proactive and make sure that we're adjusting line widths as needed to make those impedances happen rather than just testing and hoping. Johnson: That might circle back around to having orders and conversations with your customers. More complexity in this area could increase the number of holds and conversa- tions you have to have. Stevenson: Exactly. We're going to have some- body up front that is very well versed in imped- ance and able to have those conversations intelligently with our customers to make sure that we're getting what they need. It may also impact our cost of goods sold and our over- all inventory levels having to carry more lami- nate and prepreg thicknesses, different resin contents, etc., to be able to really optimize impedance for these customers. Matties: Thank you for your time today, Matt. Stevenson: Thanks for the opportunity. Johnson: Thank you. SMT007 Dr. Traian Cucu is the group leader of the Global Appli- cations and Technologies Expert Group (GATE)—R&D— at Alpha Assembly Solutions. In an interview with I-Connect007 Technical Editor Happy Holden, Dr. Cucu discussed low-temperature and lead-free soldering applications and advantages, and their recently published I-007eBook on the topic. According to Dr. Cucu, everyone in the assembly industry is looking at low- temperature and lead-free soldering for the many critical advantages that can be achieved by moving to a low-temper - ature process. "The lower thermal energy that goes into a process allows for less mechanical and thermal stress on the components, which will have an impact on the long-term performance and life of the device itself automati - cally. Again, the lifespan of an assembly will have an impact on the bottom line for all manufac- turers," he said. Dr. Cucu explained that there had been a lot of work done in the past couple of years on the first generation of low- temperature alloys. "Now, we are seeing the second generation—we might call it the second wave—of low-temperature alloys, and the third generation, which is looking to improve on those further." With the second generation, the indus- try is already close to the performance of the joint mated with a low-temperature alloy and that of a SAC alloy, according to Dr. Cucu. The third generation is already looking to improve even further for more benefits—including mechanical and ther- mal—on top of all the advantages that we see by moving to a low-temperature assembly process. (Source: Happy Holden, I-Connect007) Dr. Traian Cucu Discusses Low-temperature and Lead-free Soldering Dr. Traian Cucu