Understanding the UHDI Market

Estimated reading time: 3 minutes

“We know what we know from firsthand experience. We don’t have a surefire way to measure our progress against our peers, so we don’t put much time into worrying about it. Rather we focus on doing our part, working with our customers and suppliers to see and push what’s possible.”—Todd Brassard

The more we investigate UHDI in the current market, the more advanced packaging becomes a part of the conversation. The two emerging technologies lean on each other for their overall success. UHDI is the method by which state-of-the-art advanced packaging will be fabricated; substrates are creating a market for UHDI capabilities.

Yet there are so many questions to be answered. At the recent IPC Advanced Packaging Symposium, an organizer said he had expected the event to help refine the conversation. Instead, the size and scope of the need and the challenges to deliver on the need only got larger as the conference went on. The I-Connect007 Editorial Team met with Calumet’s Todd Brassard and Meredith LaBeau just prior to the symposium; the same sense of ambiguity is present in their conversation.

Nolan Johnson: UHDI is coming over the horizon for our industry. There are certainly IC design trends and manufacturing trends which are pushing us to even smaller features than we can do now, so this will be something that the industry needs to respond to. In a global sense, Calumet is a small shop, yet you’ve been working on UHDI. Tell us about that.

Todd Brassard: You might call it innovation for the United States, but the truth is that UHDI is a 20-year-old technology, and the U.S. is playing catch-up to offshore manufacturers. When I first tried to understand what a substrate was, much of my initial insight and perspective came from a 1990 doctoral thesis titled something like, “Quality concerns in manufacturing flip chip assemblies with organic substrates.” This was a well-formed document from over 30 years ago. I thought, “How could the U.S. PCB industry have its head in the sand for 30 years?” I suppose we all know the answer to that question at this point.

Happy Holden: During that period, I heard Nan Ya spent $400 million on a new plant to make these substrates. Whoever heard of a PCB shop that cost $400 million? All class 100, 11 stories tall, with AOI machines costing $1.5 million each.

Brassard: Some amount of capital investment is unavoidable to get into substrates, but for certain types of substrates, PCB manufacturers have 90% of the capital equipment needed, although one discovers quickly that UHDI capability is a prerequisite for most, if not all, substrates.

Johnson: Can you convert a PCB shop into a substrate shop, or do you need to build it to be a substrate shop in the first place?

Brassard: Before you can answer that question, you must understand that there are a wide range of advanced package constructions and associated types of substrate with many levels of complexity; some are definitely doable by U.S. PCB manufacturers with minimal capital investment, but more complex designs need significant CapEX investment. What level of technology does the U.S. require with respect to building substrates today, tomorrow, in the coming decades?

The right PCB manufacturers with the right equipment set, engineers, and workforce will be able to stand up solutions to meet some percentage of the industry’s immediate needs in a relatively short term. But I am confident that a subset of U.S. PCB manufacturers, in time, can and will catch and surpass the capabilities of offshore manufacturers—not the capacities or the large-scale economics, but the low-volume incredibly advanced technologies. The road is already forming before us, the U.S. will close the gap, push past the narrow definitions of SOTP and SOTA, and get back to innovating.

Let’s keep in mind that as microelectronics continue to shrink, more of the design of a system will be built on a substrate as opposed to a PCB.

Meredith LaBeau: As technology pushes to miniaturization and heterogenous integration it seems natural that the printed circuit boards of today will be the substrates of the future. The need to fan out technology will drive the build-up concept as seen in substrates. We can already witness the technology drive from HDI PCBs to UHDI build-up PCBs and substrates. This could potentially be manufacturing technology that resets the technology curve allowing for new manufacturing innovations.

To read this entire conversation, which appeared in the November 2022 issue of PCB007 Magazine, click here.