Issue link: https://iconnect007.uberflip.com/i/1361971
APRIL 2021 I PCB007 MAGAZINE 67 tions that are ripe for this type of material where voltages are up in the 20K to 160K range. ere are many applications where very high voltage is ap- plied. We see that as an adja- cent market we need to look at as well and see how that works. As for automotive— for example, the wall charg- ing systems, the trailered bat- tery systems—those types of systems all need to be man- aged. Distributing that energy, and the heat generated as well, must be managed through that material. An advantage of this material is that it has a much higher thermal conductivity than a typical FR-4. Typical FR-4 will be about 0.35 to 0.4, whereas this material is 0.7 W/mK. is gives it a much better current-carrying capaci- ty and heat dissipation capability, so that when you do have those high voltages and high cur- rents, you're not damaging the material and causing premature failure. Johnson: You mentioned that there were some other applications outside of automotive that seemed to be well suited for this material. Hunrath: e material comes in the regular building blocks that people are familiar with for multilayers. ere are many other appli- cations, everything from the ATE and burn- in boards to even some down-hole applica- tions. ere are plenty of applications where you need higher thermal performance, but you don't want to do something with a more exot- ic material. Gay: Adding to that, for example, polyimides have always been used as the primary high temperature material. e polyimides are fairly brittle and this material is just the oppo- site. It has the high temperature capability, but it's not brittle. It has a very high Tg because it's halogen-free, and it deliv- ers good temperature man- agement while maintaining its structural integrity when vi- bration is applied. It also had good temperature manage- ment when various structures within the material—copper for heat dissipation such as embedded heat sinks or coins, for example—are applied. With polyimide, you may have a hard time doing that because it creates stress risers and those stress risers crack dur- ing thermal cycling; this ma- terial is a solid material for those types of ap- plications. Johnson: So how does this material behave dur- ing fabrication? Hunrath: We have some experience with BT- based (bismaleimide triazine) materials; they drill and they smear and plate pretty conven- tionally. at's another nice thing about this material—when you try to form circuits on ce- ramics, it's a whole different, more complicat- ed and specialized technology. ere will be applications where there are certain sensors in the exhaust system that must be ceramic based. Of course, that's not an electric vehicle; that's a combustion engine. But this material can be dropped into a PCB fabricator. And that's real- ly the point—you can use conventional build- ing blocks in terms of the prepregs and cores. It also goes through the shop, drills normally, plates, and all that. Johnson: Fabricators can anticipate it behaving a lot like FR-4? Gay: Yes, FR-4 processing ease. Johnson: at certainly plugs a hole in the spec- trum of materials, doesn't it? Michael Gay