A high-speed router backplane is disclosed. The router backplane uses differential signal pairs on multiple signal layers, each sandwiched between a pair of digital ground layers. To reduce routing complexity, at least some of the differential signal pairs route through a via pair, somewhere along their path, to a different signal layer. Specific via designs reduce differential signal distortion due to the via pair, allowing the backplane to operate reliably at differential signal rates in excess of 3 Gigabits per second. In particular, each via passes through nonfunctional conductive pads on selected digital ground plane layers, the pads separated from the remainder of its ground plane layer by a clearance, thereby modifying the impedance of the via and reducing reflections from the stubs created by the via.