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Nolan’s Notes: Materials & Technology

It didn’t start with Forrest Gump—the idea that two things (or people) go together “like peas and carrots”—but that line from the movie certainly has been appropriated by Tom Hank's character in the film adaptation of the Winston Groom novel. As this issue of PCB007 Magazine came together, our editorial staff couldn’t seem to shake off the image of the vegetable combination when it came to materials and technology.

So, we’re picking up on the ongoing development of new base materials for PCB fabrication. We all see and feel the changes in dynamics that are influencing materials; our manufacturing capabilities are being pulled in multiple directions simultaneously. Some characterize it as a fracturing, others see it as an opportunity. I guess it depends on where you stand in the supply chain. We’re opening the doors to the materials’ research departments to discuss the ever-tightening relationship between the product's application and the material selected to serve as the PCB substrate.

For those who are designing boards for specialized, higher-performance applications, the choice of materials with optimized performance is an opportunity. Manufacturers are working on all three key features: performance, manufacturability, and price. This makes the conversation between design team and fabricator a multifaceted affair. As we investigated how materials are changing, we spoke in depth with Eddie Mok at WUS. Eddie is an expert in materials selection and shared some of his market research with us. The more we talked, the more Eddie’s comments validated the ideas that there is a symbiosis. Technology is driving materials; materials are driving technology. And fabs find themselves in the middle. In this issue, you’ll find one excerpt from that wide-ranging conversation as it relates to the topic at hand.

New designs—and there are a lot of them—have a wide range of choices for materials nowadays. Some materials are optimized for specific applications, such as automotive, high-speed, or RF. While that’s been the case for a while now, it’s safe to say that materials development to meet application-specific needs has accelerated. And since these materials now play an active role in delivering on performance specifications, the selection becomes a critical engineering function.

Mok makes the point that fabs must validate a material to add it as an offering. That validation process takes time and resources to complete. With so many new materials, the fabs are hard-pressed to validate even a few, let alone all the likely options. And yet, how can a design team get hard data on performance except to build using that material?

For fabs and designers who aren’t on the vanguard of high-performance design, things are a bit more stable—or so people think. But are they, really? And should they be? A PCB assembly’s current material may be good enough, as they say, but what if a tweak in material selection reduces overall manufacturing cost? What if that tweak simultaneously improves the performance of the existing design? And is it worthwhile to redesign to take full advantage of a new material? In the spirit of continuous improvement, doesn’t it make sense to investigate these new materials? But who to talk to, and which materials manufacturers should you pay attention to?

The answers to these questions vary depending upon whether you’re a fabricator or a designer/engineer, of course, and on how you’ve structured your input materials supply line. To add more detail to the applications table that Mok kindly shared with us, we reached out to all the suppliers on the table, plus a couple others not on Mok’s radar (as impressive as Mok’s list of suppliers is, it doesn’t represent the entire industry). That is a lot to ask of any one source, to share insight on their current development activities. The rest of the features in this issue give those materials manufacturers who submitted some space to share that work. What appears here does indeed provide a peek into the development and innovation underway.

Yes, clearly the technology (both design and fabrication), and the materials themselves, are increasingly interlinked. Materials are ever increasingly becoming a part of the engineering design work. Back in the 1980s, when electronic design tools were an emerging, disruptive industry, logic simulation was one of the first “killer apps” for electrical engineers. SPICE and sophisticated timing simulation was right there, too. In IC design, electrical field parasitic effects calculation was an early simulation application that helped design teams improve their work.

Doesn’t it seem time to bring material performance into the PCB simulation and verification space? Is that our next “killer app” in PCB design? It sure seems like that would be the right bowl in which to put our peas and carrots, don’t you think?

This column originally appears in the March 2022 issue of PCB007 Magazine.