HDI (High Density Interconnect)
HDI structures is found complex PCB:s, where often you are short of space in the finished product.
Often occurs in boards with 4 layers and up, with blind and buried vias and small holes. The structures are often narrow and tight trace and insulation. We can provide down to 50 microns width wire and insulation.
Blind vias can only be done with the ratio 1:1 ie. 0.1mm vias can be drilled 0.1mm deep, etc.
A blind via can be drilled to a deeper layer as long as the 1:1 ratio is maintained.
Micro vias can be copper filled or filled with resin and overplated to get an even surface and this should be done when the hole is located in a SMD pad.
Stacked micro vias is drilled in straight line on top of each other. A micro via can also be drilled into a filled and over plated buried via.