Patent ID: RE41242

Claim:
A package board having comprising: a core board on each surface of which ; a plurality of conductor circuits are formed with an interlaminar resin insulating layer therebetween on each surface of the core board , wherein a plurality of soldering pads are formed on an IC chip mounted side surface , as well as of said core board and on an other side surface of said core board to be connected to another board, so that said soldering pads on the other side surface are larger than those said soldering pads on said IC chip side surface of said package board, and said IC chip mounted side surface has a dummy pattern for improving the mechanical strength of the package board is comprising a metal and formed between signal line conductor circuit patterns formed on said IC chip mounted side surface of said core board such that a rate of metallic portions on said IC chip mounted side surface and the other side surface is adjusted to improve mechanical strength of the package board .