A drill bit for use in back drilling of a printed circuit board (PCB) is provided. The drill bit includes a cylindrical body having an outer surface and an end surface, the end surface being substantially perpendicular to a vertical central axis of the cylindrical body. The end surface defines at least one cutting portion. The drill bit also includes a non-conductive coating layer disposed over the cylindrical body proximal to the end surface and at least a portion of the end surface. The at least one cutting portion remains uncoated.