Zero clearance backdrilled printed circuit boards

A multi-layer printed circuit board (PCB), comprising:

• a plurality of signal-trace layers, each signal-trace layer having a plurality of signal traces;
• a plurality of voltage-plane layers, each voltage-plane layer having at least one voltage plane;
• and
• a plurality of plated-through-hole vias disposed in the multi-layer PCB, each plated-through-hole via having a conductive barrel,
• wherein a first portion of the plated-through-hole vias have conductive barrels that extend from the first outer surface to a conductive barrel inner end located within the multi-layer PCB, and corresponding backdrilled shafts that extend from the conductive barrel inner end to the second outer surface, and
• wherein a first voltage plane of a first voltage-plane-layer abuts at least one backdrilled shaft.

A method, comprising:

• providing a multi-layer printed circuit board (PCB) comprising:
• a plurality of signal-trace layers, each signal-trace layer having a plurality of signal traces;
• a plurality of voltage-plane layers, each voltage-plane layer having at least one voltage plane;
• and
• a plurality of plated-through-hole vias disposed between a first surface of the multi-layer PCB and a second surface of the multi-layer PCB, wherein each plated-through-hole via includes a conductive barrel;
• wherein each signal trace is spaced apart from every conductive barrel of the plurality of plated-through-hole vias by a predetermined minimum distance other than any conductive barrel with which the signal trace is in direct contact, and
• wherein a first voltage plane of a first voltage-plane layer is in direct contact with the conductive barrel of each of at least a portion of the conductive barrels of the plurality of plated-through-hole vias;
• and
• backdrilling one or more of the plurality of plated-through-hole vias to form a corresponding one or more backdrilled shafts,
• wherein, after backdrilling, the first voltage plane abuts at least one backdrilled shaft.