Wiring board having through hole or non-through hole, and method for producing the same

摘要

There is provided a circuit board including a substrate having a hole. Inside the hole, a metal wiring is formed. The wiring is made of a solder alloy having a melting point of 100 to 600° C., and the metal wiring includes a polycrystalline region of the solder alloy. The metal wiring of the present invention is superior in conductivity.