A substrate with stacked vias and fine circuits and a method for
fabricating the substrate are proposed. A core layer is formed with a
metal layer respectively on upper and lower surfaces thereof, and at least
one through hole. A first insulating layer is applied over the metal layer
on the upper surface of the core layer and selectively formed with at
least one first opening for exposing the metal layer. A metal layer is
formed within the first opening, and a second insulating layer is applied
over the first insulating layer and formed with a plurality of second
openings, wherein the metal layer within the first opening is exposed via
at least one second opening. After a conductive layer is applied over the
second insulating layer and within the second openings, a metal layer is
formed within the second openings. Finally, the conductive layer is
removed by micro-etching.
