Systems and methods for removing undesired metal within vias from printed circuit boards

A method of modifying a via of a PCB to form a stub-less through-hole, the method comprising:

• drilling a via of the PCB comprising an unwanted material to form a through-hole by removing the unwanted material in the via of the PCB;
• depositing a seed material directly over an inner wall of the through-hole, wherein the seed material is a seed for plating a conductive material;
• back drilling a first portion of the through-hole by using a drill from the top of the PCB to form a first blind via, wherein the drill drills through the seed material and automatically stops drilling at an internal conductive trace of the PCB;
• and
• selectively plating the conductive material over the seed material to form a stub-less plated through-hole,
• wherein the drill comprises:
• an inner core comprising a conductive material;
• an outer coating layer comprising a non-conductive material disposed over the inner core, the outer coating having a first and a second vertical portions and a horizontal portion under a bottom of the inner core, the first vertical portion having a first tip end and the second vertical portion having a second tip end opposite to the first tip end near the bottom of the inner core;
• and
• a coating disposed over the outer coating layer near the bottom of the inner core between the first and second tip ends.