PCB HDI Overview

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HDI PCB is defined as a printed circuit board with a higher wiring density per unit area than a conventional PCB. They have much finer lines and spaces, smaller vias and capture pads, and higher connection pad density than employed in conventional PCB technology.

PCB HDI Detailed introduction

HDI (High Density Interconnect): High Density Interconnect technology is a technology that uses blind / buried vias to enable higher density PCB circuit distribution. The advantage is that it can significantly increase the usable area of the PCB and make the product as miniaturized as possible. However, due to the higher density of line distribution, it is not possible to drill through holes by traditional drilling methods, and some of the through holes must be blind drilled by laser drilling or interconnected with internal buried holes.

Generally speaking, HDI circuit boards are built up by using the Build Up method, where the internal layers are first made or pressed together, and then the outer layer is covered with insulation layer (prepreg) and copper foil after laser drilling and electroplating of the outer layer is completed, and then the outer layer is repeatedly wired, or laser drilling is continued to stack up the layers one at a time.

Since laser drilling is used many times, the key to the quality of HDI boards is the hole shape after laser drilling and whether the holes can be filled evenly after subsequent electroplating.

The following is an example of HDI board type. The pink hole in the picture is a blind hole, which is made by laser drilling, and the hole diameter is usually 3~4 mil; the yellow hole is a buried hole, which is made by mechanical drilling, and the hole diameter is at least 6 mil (0.15 mm).

PCB TAIWAN - HDI PCB

PCB HDI manufacturer

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