Are Domestic Assemblers Ready for the Next Level of Electronics Miniaturization?

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UHDI technology is more than another evolutionary level of miniaturization. It’s a fundamental change in how we create circuit boards, on a scale potentially as impactful as the transition from through-hole to surface mount was 40 years ago. 

Traditional and high density interconnect (HDI) PCB manufacturing technology that uses subtractive copper etching processes cannot repeatably produce features below 75 microns and vias below 150 microns. UHDI fabrication blows those limits away with additive or semi-additive processes that can produce lines and spaces as small as 12 microns and vias of 75-100 microns, increasing circuit density by a whopping 10–30X. 

UHDI is not new or uncommon technology. It’s in the palm of our hands as it’s been in mobile products since the iPhone 6 launched in 2014. While it has proven its capabilities in consumer electronics, it needs significant development and evaluation to be considered robust enough for aerospace and defense electronics, where the benefits of miniaturization are extensive, but the implication of malfunction is far greater than in similar consumer-grade devices. 

As with most modern PCB fabrication technologies, Asia leads America in the development and scaleup of UHDI. To realize the multitude of benefits from PCB densification in security and defense electronics, the U.S. government has begun funding R&D for domestic PCB fabrication, and several shops are gearing up to produce UHDI technology for high-performance, high-reliability applications. While the fabrication industry is abuzz with news of innovative materials, processes, and technologies, the assembly side has remained relatively quiet.

To read the entire article, which published in the February 2025 issue of SMT007 Magazine, click here.