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What is HDI PCB technology?

High density interconnect, or HDI, circuit boards are printed circuit boards with a higher wiring density per unit area than traditional printed circuit boards (PCB). In general, HDI PCBs are defined as PCBs with one or all of the following: microvias; blind vias, buried vias or other microvia technique; built-up laminations and high signal performance considerations. Printed circuit board technology has been evolving with changing technology that calls for smaller and faster products. HDI products are more compact and have smaller vias, pads, and lines and spaces. As a result, HDIs have denser wiring, which means lighter, compact, lower layer count PCBs. Rather than using a few PCBs in a device, one HDI board can house the functionality of the previous boards used.


Microvias play a big role in the size and capabilities of HDI boards.

Smaller vias can be closer together, leading to a smaller board or freeing up space for additional components. Microvias have smaller aspect ratios than through-hole vias, and provide greater reliability for HDI boards than other vias.

As the semiconductor and electronics market called for smaller, but higher function products, HDI found its place in design engineers' arsenal. Shortening the distance between devices, or trace space, and using a large number of transistors translated to better performance in electronics.

The compact HDI boards provides better electrical performance and lowered power consumption while still maintaining close spacing between components.

Signal integrity is improved due to the shorter distance connections and lower power requirements. Other performance improvements over conventional PCBs include stable voltage rail, minimal stubs, lower RFI/EMI, and closer ground planes and distributed capacitance.