Issue link: https://iconnect007.uberflip.com/i/1464168
18 DESIGN007 MAGAZINE I APRIL 2022 Happy Holden: You're balancing the losses between the dielectric losses and the cop- per losses, and the fields that they produce. As things get smaller, with the fields that are active, everything becomes infinitely more complex. Torp: Yes, the high-speed digital is a little bit eas- ier than the high-frequency stuff. I was recently at the IMAPS Device Packaging Conference, and they're really going down in lines and spaces, headed toward glass interposers. ey were talking about going down to 2-micron lines and spaces on glass, which is an extremely challenging thing. It's not the revenue center of gravity, at this point. But that's leaning toward the cutting edge, depending on how close you want to be to it. Matties: Now, with the designers working with an additive design, what material selections or considerations should they have in mind? How does that vary? Torp: We're working with a lot of high-fre- quency materials. We try to stay copper-clad laminate supplier-independent. We like to work with them all. But you start to see more of the higher-temperature, higher-frequency materials—the PTFE and the ceramic-filled type materials. en, we also do a lot of work on the FR-4 traditional epoxy materials. en you start to look at some of the poly- imide materials, which have their own set of issues. ey move around a little bit. ey tend to be a little bit more hydroscopic and create some dimensional issues that you must com- pensate for. at's the biggest thing with some of the material selections. ere are quite a few things happening with additive before we standardize on a process; a lot of the standards are rear-view mirror kinds of things. Shaughnessy: Are there currently IPC stan- dards for additive or semi-additive? Torp: ere are some standards and standards committees coming online for additive. ere's the Ultra High-Definition Committee that's recently been formed. e Sintering Materi- als Committee just finished its first publication of a standard, so they're looking at alternative material types with respect to putting met- allization down onto the substrates. ey're looking at a lot of nano-sintering materials, and copper-based materials to get a copper-to- copper interconnect. en there are also committees dedicated to textiles and alternative substrates as well, because people are trying to put this on quite a variety of materials. e IPC does have quite a few new standards committees working on the additive technology; much of it is around the conductive inks that are being supplied to the industry. Shaughnessy: Can you use a regular field solver to model additive and semi-additive designs? Torp: Yes. We've engaged a few designers to help us with signal attenuation. at's not nec- essarily our core competency. But we do have a couple of folks very good at modeling capabili- ties who help the designers model the circuitry. Shaughnessy: Very cool. If someone is using any of the main EDA tools, do they have to