Patent ID: 7271349

Claim:
An apparatus, comprising: a printed circuit board comprising first and second conductive layers disposed on opposing surfaces of a substrate of a first dielectric material; a first clearance hole formed through the first and second conductive layers and the substrate; a second clearance hole formed through the first and second conductive layers and the substrate; a coating of a second dielectric material disposed on an inner edge of the first and second conductive layers and the substrate that form the first and second clearance holes, wherein the second dielectric covers a side of the first conductive layer, a side of the second conductive layer, and a side of the substrate within the first and second clearance holes; a first signal routing layer separated from the first conductive layer by a first dielectric layer of a third dielectric material; a second signal routing layer separated from the second conductive layer by a second dielectric layer; a first plated-through via disposed between the first and second signal routing layers through the first clearance hole, the plated-through via electrically insulated from the first and second conductive layers and the substrate by the second dielectric material; a second plated-through via disposed between the first and second signal routing layers through the second clearance hole, the plated-through via electrically insulated from the first and second conductive layers and the substrate by the second dielectric material; and a first and second signal traces in the first signal routing layer disposed between the first and second plated-through vias.