The present invention prepares a member having a potrusion-forming copper foil 21 formed on a conductor-circuit-forming copper layer 23 via an etching-barrier layer 22 formed of a different metal. Etching is selectively performed for the protrusion-forming copper foil 21 by using etchant that does not etch the etching-barrier layer, and protrusions 25 are thereby formed. Then, the etching-barrier layer 22 is removed using etchant that does not etch the copper foil 23 and using the protrusions as masks. An interlayer-insulating layer 27 is formed on a surface of the copper foil 23, on which the protrusions 25 are formed, so that the protrusions are connected to the conductor circuit. Thereby, heights of the protrusions are uniformed, and the reliability of connections can be improved.