Patent ID: 7902659

Claim:
A package substrate comprising: a core substrate; a conductive layer formed on the core substrate; an interlayer resin insulating layer including a filler comprising an inorganic compound, the interlayer resin insulating layer being formed on the core substrate and the conductive layer; a pad structure formed on the interlayer resin insulating layer, the pad structure comprising a via hole formed through the interlayer resin insulating layer and directly on the conductive layer to electrically connect the pad structure to the conductive layer; a solder resist formed on the interlayer resin insulating layer and the pad structure, the solder resist having an opening exposing a partially exposed portion of the pad structure; and a conductive connecting pin configured to establish an electrical connection with another substrate, the conductive connecting pin being secured to the partially exposed portion of the pad structure via a solder, the solder being disposed over at least one metal layer formed in the partially exposed portion of the pad structure, wherein the at least one metal layer is formed in the partially exposed portion of the pad structure after the opening is formed in the solder resist.