Issue link: https://iconnect007.uberflip.com/i/1479191
44 PCB007 MAGAZINE I SEPTEMBER 2022 rity related budgets are getting tighter. ere's always a drive to reduce layer count. You're right that every time you add two layers, you add 20% or more to the cost. at's a consis- tent and traditional cost bump. e lesson is to keep layer count down. e engineers design- ing the lower end servers—like you see in server farms—have a maximum layer count because they're trying to keep material costs down. In addition, they don't use the low-loss materi- als that they'd love to use, simply because they can't afford them. In the high-end servers, cost is not as much a concern as loss. It depends on the application. I liked your recent Design007 Magazine issue on design for manufacturing, especially the sections that discussed the designer's linkage to manufacturers, and just how many steps away from the manufacturers the designers are now. at part really hasn't changed too much over the years. It's getting worse, too, because the buyers make uninformed decisions when they specify the material in a drive to reduce costs vs. optimizing the material properties for the design. Johnson: Compare that to the 1970s, when everybody in my neighborhood worked at Tektronix and the electro-chem facility was across the street from offices of the teams designing the circuit boards. All you had to do was walk over and talk to techs on the fabrica- tion floor about what they could do, and back- and-forth you go throughout the entire design phase. Korf: In those days, a lot of the big companies— Tektronix, Digital Equipment, Data General, or IBM—had their own shops where you could tune it to the designer's cost and performance. ey could drive technology inside because they had high profit margins. ey also spent more time on research; we've lost a lot of that. Andy Shaughnessy: I'm amazed that so many boards get through. So many designs are suc- cessful even though they're not talking to the fabricator until the very last minute. Korf: I had a conversation with a person in the IC industry last week about how bad our data files are, how we need to improve that with 3D technology, and that we have a chance to start from scratch. He says, "What you mean? ey're always good." I said, "No, you came out of the IC fab business where a mistake would cost maybe $100,000. Here we fix it for free." It was painful to make a mistake and have a bad data file in the IC industry, but not a board fabricator. Unfortunately, that's the core of the problem. From the design side, though, rel- ative to materials, it's a traditional problem. ey must get the cost as low as possible vs. a little bit more expensive material to improve circuit performance or reliability. at's what they're driven for. Strubbe: e challenge continues. It's just more people are getting increasingly higher speeds, so they must worry about more things. In the old days, we had a board designer, the per- son who laid the board out once we had CAD tools. ey came out of the draing industry. ey were primarily draing people but nowa- days they're electrical engineers because there are so many constraints. Johnson: Right. at's the transition. Korf: Yes. e trend I'm talking about is not so much from just TUC; it's everyone who is pro- viding materials to this market. e biggest supplier in the world just makes low-end FR-4 and CEM materials because that's their mar- ket. It's huge, so there's plenty of customers/ volume in that space. Johnson: I think this is really good. ank you, Dana and John. Korf: Always a pleasure. We enjoyed it. PCB007