US Patent 7728421 Semiconductor device

Plural via portions formed on a package substrate of a BGA include a first through-hole portion extended in the plane direction by an extension wiring connected to a land portion and a second through-hole portion that is arranged on the land portion serving as pad-on-via, whereby high-density wiring and multi-function of the BGA can be realized by using the package substrate having a two-layer wiring structure. Accordingly, cost for the package substrate can be reduced, and hence, cost for the BGA can be reduced, compared to a multi-layer wiring structure having four or six wiring layers.