A method of forming a multi-layer structure over an insulating layer comprises the steps of: selectively depositing a barrier layer on a predetermined region of an insulating layer by use of a first deposition mask; selectively depositing a metal seed layer made of a metal which is different in substance from the barrier layer by use of a second deposition mask, so that the metal seed layer extends not only on an entire surface of the barrier layer but also a peripheral region positioned outside the predetermined region of the insulating layer; and forming a metal plating layer made of the metal of the metal seed layer, so that the metal plating layer is adhered on the metal seed layer whereby the metal plating layer is separated from the barrier layer and also from the insulating layer.