SMTA UHDI Symposium 2025, Part 1: Challenges and Solutions

Estimated reading time: 7 minutes

It’s not often you get a lunch break while watching baseball fields readied for spring training, only to head back inside for a conference on cutting-edge PCB technology. But that was the case on Jan. 23, when SMTA hosts its second annual Ultra High Density Interconnect Symposium at the Peoria Sports Complex in Arizona, a highly pro-business state with a special affection for the tech sector. It’s home to the biggest Intel semiconductor fab in the United States and the new TSMC chip fab.

With an intimate group of approximately 50 attendees, the SMTA event offered a great forum for learning, interactive discussion, and networking.

“The SMTA Ultra HDI Symposium is an exciting event for the PCB industry,” said organizer Tara Dunn. “It brings together experts in design, fabrication, and assembly to share knowledge and work together. By doing this, it helps everyone learn about ultra HDI technology more quickly and move the industry ahead.”

The day began with a breakfast presentation by Gayle Towell of AIM Solder, followed by Chys Shea of Shea Engineering, who updated us on her efforts to develop the UHDI assembly test vehicle. Chrys never disappoints in content or delivery. She wielded an old-school Magic 8 Ball, “because there are so many unknowns in UHDI.” She also discussed the evolution of technology complexity from 2017 to today, passing around tiny board examples that featured .004" and .002" traces. “We have moved from mils to microns,” she said. Chrys handed out Post-It Notes and asked attendees to write down what they would like to see in further development of this test vehicle. The design for the new test vehicle is due to go to CAD this week.

Up next was Paul Cooke of AGC Multi Material America, who covered the growing need for smooth copper to be used in applications such as AI and data servers, and challenges such as thermal expansion and reliability. A proponent of what he has nicknamed “the glassless revolution,” Paul said, “I am trying to drive the industry to a non-reinforced material revolution.”

He reminded attendees that we are in the midst of a global glass shortage that will get only worse due to the supply being sucked up by AI technology needs. AGC’s no-glass fastRise™ products do not have a real Tg and are 33 to 125 microns thick. The company’s latest material is fastRise HF, with others in development, including fastRise X (IoT, servers, AI, 5g, ADAS) with samples available for testing.

Paul reminded the group that the last North American copper supplier (Denkai America) had just closed its doors, potentially making additive processing and using less copper more attractive. Staying with copper foil may become the more expensive approach at some point due to the lack of local sourcing. With UHDI boards, yield is the most critical factor in controlling cost, a fact which may eventually push manufacturers toward the adoption of more additive processes, which also produce far less waste.

Electroninks COO Mike Vinson discussed complex metal inks and additive manufacturing, something that PCB007 Magazine has covered in recent years. Mike started his career at Texas Instruments and has had a front-row seat in the development of printing technology. He discussed the metal organic decomposition (MOD) inks his firm has developed particularly for UHDI applications, explaining that MOD ink is a seed layer as he walked us through plating and peel strength comparisons.

Mike listed the great challenges for adoption of this technology, which include:

• Manufacturing complexity
• A lack of Industry standards
• Design challenges
• Thermal stress
• SI (enhanced signal integrity with a 1:1 aspect ratio for metal traces)
• Reliability
• Supply chain limitations
• Testing, inspection, and repair
• Integration with existing technologies
• Cost

As with all new technologies, the lack of standards is a significant issue and barrier for this type of ink. Mike said IPC is actively working a new standard for this technology, and he spent some additional time talking about global business realities, geopolitical challenges, and the spotlight IPC is putting on the supply chain issues.

Mike concluded by highlighting the need for greater collaboration among industry leaders both for the proliferation of additive manufacturing and in order to achieve a robust UHDI ecosystem.

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