Circuit board and method of making circuit board

摘要

A circuit board comprises a board substrate including a substrate layer formed with a pad on an upper surface thereof, and a metal piece soldered on the pad. At least one through-hole including an internal wall formed with a conductive film is provided at a portion corresponding to the pad on the substrate layer. The through-hole is filled with a predetermined filler for closing at least an open mouth of the through-hole at the upper surface of the substrate layer. The pad is connected integrally with the conductive film on the internal wall of the through-hole.