Why UHDI is pushing the limits of what’s possible
In this episode of the Printed Circuit Podcast, host Steph Chavez sat down with Anaya Vardya, CEO of American Standard Circuits (ASC), to dive into one of the most critical advancements in PCB technology: ultra high density interconnect, or UHDI.
While the term UHDI might feel new to some in North America, the technology has been a staple in Asia for years. But as Vardya explains, global supply chain shifts, national security concerns, and renewed investment in domestic manufacturing have pushed UHDI back into the spotlight for U.S. designers and fabricators.
What exactly is UHDI?
Ultra high density interconnect refers to boards with microvias under 75 microns, lines and spaces under 50 microns, and dielectric thicknesses in the same sub-50 micron range. “That’s thinner than a human hair,” Chavez pointed out. And it’s not just a design challenge—it’s a full stack rethinking of how PCBs are built.
“You can design anything on a computer screen,” said Vardya. “But the trick lies in translating that design into a fabricated product, and doing it repeatedly, at scale, and with quality.”
In industries like defense, aerospace, and medical, North American companies are increasingly looking for secure, domestic sources for complex PCB builds. With more funding flowing from government initiatives like the CHIPS Act, there’s growing pressure and opportunity to bring this capability stateside.
“We gave up this technology leadership to Asia years ago,” Vardya admitted. “Now, the conversation is back because of IP concerns and advanced defense programs.”
UHDI enables designing smaller, smarter, faster
“Sometimes, it’s the only way to meet the space constraints,” said Vardya. He pointed out that designs requiring tight control over impedance or improved RF performance benefit from the straight, rectangular traces UHDI enables. Unlike traditional trapezoidal traces, these straight profiles allow for more precise electrical behavior.
Chavez emphasized the importance of fabricator collaboration: “This is not the kind of tech you just throw over the wall. Without partnership upfront, you’re setting yourself up for delays, redesigns, and rework.”
Like any advanced tech, UHDI comes with trade-offs. Sequential builds are often required, meaning longer lead times and more hands-on process control. “You don’t want to use it just because it sounds cool,” Vardya cautioned. “Only use it if your design truly demands it.”
He’s seen customers ask for stacked microvias and complex layering, then request a 10-day turnaround. “Totally unrealistic,” he said. “That’s the disconnect between the CAD screen and the fab shop.”
Walk the floor, learn the process
Both Chavez and Vardya stressed how valuable it is for designers to visit a fabrication or assembly shop.
“It’s eye-opening,” said Chavez. “You start to understand just how much detail, handling, and process control goes into building what you sketched on a screen.”
UHDI fabrication involves not just fine lines, but incredibly delicate materials like 12-mil dielectric cores which are thinner than paper. Contamination control, microvia copper filling, high-resolution solder masks, and advanced AOI and electrical test capabilities are just the beginning.
“And solder mask is often overlooked,” Vardya added. “You’re talking about 50-micron mask openings. That’s not trivial.”
Typical UHDI applications and U.S. momentum
While cell phones remain the most well-known use case, ASC is seeing UHDI spread across medical, aerospace, and industrial sectors.
“We’re working under NDAs for most of these projects, but they’re real, and they’re happening here in the U.S.,” Vardya shared. “A lot of them involve flex materials or LCP. The materials are evolving just as fast as the board designs.”
ASC doesn’t just fabricate PCB boards, they aim to educate. From downloadable design guides to direct consulting with experts like John Johnson, their goal is to help engineers design smarter from the start.
“Don’t just download a guide and go,” Vardya said. “Give us a call. Let’s talk about what you’re building and how we can help.”
Chavez echoed that sentiment. “There’s so much value in that early collaboration. And what ASC is offering the industry — through education and partnership — is gold.”
UHDI isn’t futuristic anymore — it’s current, it’s necessary, and it’s tough. But with early engagement, smart design, and a trusted fabrication partner, it’s absolutely achievable.
“As we say at ASC,” Vardya concluded, “collaborate to win.”
Learn more expert advice on ultra high density interconnect and listen to the Printed Circuit Podcast.
