Patent ID: 7155821

Claim:
A method for manufacturing a circuit board, the method comprising: obtaining a plane-shaped structure having layers of circuit board material integrated together; carving a hole within the plane-shaped structure, the carved hole including an inner portion having a substantially uniform inner portion diameter and a connecting portion disposed between the inner portion and an outer surface of the plane-shaped structure, at least part of the connecting portion having a diameter which is larger than the substantially uniform inner portion diameter of the inner portion to improve access to the inner portion; and performing a plating process on the plane-shaped structure to provide plating over the hole carved within the plane-shaped structure, the provided plating forming a countersunk via which provides an electrical pathway from the outer surface of the plane-shaped structure to an internal circuit board trace; wherein carving the hole includes: applying a countersinking drill bit to the plane-shaped structure in a single drilling operation to drill the hole within the plane-shaped structure, the countersinking drill bit having an elongated tip and a countersinking base, the elongated tip being configured to form the inner portion having the substantially uniform inner portion diameter, the countersinking base being configured to form the connecting portion disposed between the inner portion and the outer surface.