Some embodiments relate to micro vias in printed circuit boards (PCBs). In an example, a PCB may include a PCB substrate and a micro via. The micro via may extend between opposing surfaces of the PCB substrate and may have a diameter less than or equal to about 100 microns. In another example, a method of forming micro vias in a PCB may include forming a through hole in a PCB substrate of the PCB. The method may also include positioning a pillar that is electrically conductive within the through hole. The method may also include backfilling the through hole around the pillar with an epoxy backfill.