What’s A HDI Printed Circuit Board?

HDI stands for High Density Interconnect. HDI PCBs have finer traces and trace spacing, laser drilled
micro vias and higher connection pad density. Its two chief advantages are that it permits the use of
fine pitch BGAs and it reduces the number of PCB layers required because the finer traces and smaller
vias allow more circuitry in a smaller area.

Narrow trace widths mean higher circuit density

At PNC standard PC Board fabrication uses a minimum trace width of 5 mil, with a 5 mil
space between traces (5/5mil) PNC’s HDI trace widths can be as narrow as 3 mil with 3
mil spacing. These finer traces allow 160% more traces in the same real estate. 3/3mil
spacing will also allow two traces to escape between pads of a standard BGA, meaning less
PCB layers are needed to fan out the pins from the BGA.