What is Ultra HDI?
September 22, 2023 | Happy Holden, I-Connect007Estimated reading time: Less than a minute
Ever since high-density interconnect (HDI) was created in 1982 by Hewlett-Packard to package its first 32-bit computer powered by a single chip, it has continued to evolve and provide the solutions for miniaturized products. The leading edge of HDI technology became the process used for organic flip-chip packaging for the semiconductor industry. The two distinct markets—IC substrates and product-system integration—are now colliding and utilizing the same ultra-HDI manufacturing processes (Figure 1).
Introduction
These two markets have different characteristics as well as specifications. The middle ground is currently occupied by the very high-density PCBs called substrate-like PCBs (SLPs).
The differences lie in that IC packaging is for components of unspecified final application while an HDI PCB is the result of a system-integrated product. But time and evolution have introduced a semiconductor component system integration strategy which the IEEE now calls heterogeneous integration.
Reference:
- Inspired by IEEE Heterogeneous Integration Roadmap, Chapter 2, pp 10.
Continue reading this article in the September 2023 issue of PCB007 Magazine.
Testimonial
"Your magazines are a great platform for people to exchange knowledge. Thank you for the work that you do."
Simon Khesin - Schmoll MaschinenSuggested Items
UHDI Fundamentals: UHDI Technology and Automated Inspection
11/03/2025 | Anaya Vardya, American Standard CircuitsFollowing up on the last article on integrating ultra high density interconnect (UHDI) PCB technologies and Quality 5.0, here we will do a deeper dive into the automated inspection component. UHDI applications demand extreme precision, with line/space dimensions below 25 µm and microvias below 30 µm. Automated inspection systems are essential to achieving the defect-free fabrication required at these scales, and legacy automated inspection systems are becoming obsolete and ineffective.
On the Line With… Ultra HDI Podcast—Episode 7: “Solder Mask: Beyond the Traces,” Now Available
10/31/2025 | I-Connect007I-Connect007 is excited to announce the release of the seventh episode of its 12-part podcast series, On the Line With… American Standard Circuits: Ultra HDI. In this episode, “Solder Mask: Beyond the Traces,” host Nolan Johnson sits down with John Johnson, Director of Quality and Advanced Technology at American Standard Circuits, to explore the essential role that solder mask plays in the Ultra HDI (UHDI) manufacturing process.
Connect the Dots: Designing for the Reality of UHDI PCBs—Drilling
11/04/2025 | Matt Stevenson -- Column: Connect the DotsUltra high density interconnect (UHDI) PCBs are changing the game in designing for the reality of manufacturing. With both consumer and industrial electronic devices becoming more advanced, the demand for UHDI PCBs will grow. That means we’re all likely to be designing more UHDI boards. UHDI advanced miniaturization technology challenges designers with regard to both board thickness and footprint. Designers will face more variables in every aspect of design creation. This is certainly the case with drilling.
MKS’ Atotech Showcases Next-gen PCB and Substrate Manufacturing Solutions at CPCA Plus 2025
10/24/2025 | MKS Inc.MKS Inc., a global provider of enabling technologies that transform our world, announced its participation in CPCA Plus Show 2025, taking place October 28 – 30 at Shenzhen International Convention and Exhibition Center.
Global Electronics Association Releases Fall Schedule of Instructor-led Courses
10/20/2025 | Corey Lynn, Global Electronics AssociationWhether you’re looking to enhance your PCB design skills, explore advanced packaging technologies, or deepen your understanding of reliability, these Global Electronics Association courses deliver high-impact learning from the best in the industry. Here are a few starting this week.