The rapid proliferation of 5G/6G communications, Internet of Things (IoT), high-performance computing (HPC), AI, and medical electronics has driven the need for increasingly compact, high-performance circuit packaging. UHDI, defined by feature sizes well below traditional HDI, addresses these demands by enabling ultra-fine lines, dense via interconnects, and embedded passive functionality. Understanding the materials and layering strategies in UHDI is essential for advancing both manufacturing and application design.
Substrates and Dielectrics
UHDI technology represents the next evolutionary step beyond traditional HDI PCBs. Characterized by sub-15 μm line/space resolution, stacked and staggered microvias, and ultra-thin dielectric layers, UHDI enables miniaturization, high-frequency performance, and integration of advanced functionalities. This article provides a high-level overview of the materials and layer structures that underpin UHDI, and highlights their properties, advantages, challenges, and ever-increasing applications across every market sector.
Dielectric Substrates
UHDI requires dielectric layers as thin as 10–15 μm, enabling short microvia depths and multiple build-up cycles (sequential lamination). The thinness supports high interconnect density while maintaining mechanical reliability.
To continue reading this article, which originally appeared in the November 2025 edition of Design007 Magazine, click here.