Issue link: https://iconnect007.uberflip.com/i/1464168
16 DESIGN007 MAGAZINE I APRIL 2022 the designers to work with us on their specific opportunities and processes. en we build prototypes for them, and later they come out and do the thermal cycling and environmental stress testing. ey say, "Wow, this is pretty interesting stuff. We didn't quite think about it the way you guys think about it." It's an alternative type of process. Normally, it's in the areas where people struggle with the material set, the low Dk, high-frequency materials set is one that we've had the great- est amount of interest in, especially, from the defense electronics guys. Matties: When you say it's proprietary, is that refer- ring to the design process? Torp: It's the fabrication process. e order of the process is a little bit differ- ent than what they're used to, but we're using all the same set of materials that they're used to. From a reliability standpoint, you have similar outcomes; it's just not the same order of operation. You're still using the same electroless copper and electrolytic copper, but the way you're connecting the dots, so to speak, is a little out of sequence. Matties: So, if a traditional PCB designer wants to learn how to do additive design, is it impor- tant that they talk to the manufacturer building the board? Torp: Yes, you really need to talk to the fabrica- tors building the boards. at's where the real- ity, the product realization, comes in. ere are not many board fabricators in the world actually doing this, and they're keeping much of their processes under lock and key. Matties: Do you see a growing market for addi- tive and semi-additive? Torp: Yes, there's very big market growth area because the complexity and the number of connections on the board is increasing, espe- cially with the laser-drilling of microvias. Matties: When should the designer consider using additive? What's the trigger point for that decision being made? Torp: I would say the lines and spaces are the triggers. Once you start to get below, let's say, one mil or 25-micron lines and spaces, you start to see an increased desire to move toward the additive pro- cess, rather than to try to do it in the semi-additive process. It comes down to being able to control plat- ing within the process, and especially your regis- tration at that point. It's a very difficult thing to go below 25-micron lines and spaces. at's where the design- ers must tell us what their requirements are, par- ticularly for signal-to- noise ratio impedance. e dielectrics are get- ting more like glass in terms of trying to get to the operating frequencies where the HF/RF guys operate. is is where additive comes in. It's just a spooky environment. e high- speed digital stuff is not as bad as the high-fre- quency designs. I know Happy can expound upon that. e high-frequency engineers are very knowledgeable folks, and they light up when you start to talk about the high-frequency space.