A wiring layer is covered with a first organic SOG layer, a reinforcement
insulating layer consisting of a silicon oxide film or a silicon nitride
film formed by means of a plasma CVD method, and a second organic SOG
layer, in this order. A via hole is formed in the first organic SOG layer
and the reinforcement insulating layer, and a trench is formed in the
second organic SOG layer to correspond to the via hole. A conductive via
plug and an electrode pad are embedded in the via hole and the trench,
respectively. The second SOG layer is covered with a passivation layer in
which a through hole is formed to expose the electrode pad. A wire is
connected to the exposed electrode pad in the through hole.
