Patent ID: 8164186

Claim:
A ball-grid array (BGA) semiconductor device comprising: a semiconductor package including a package substrate having first and second main surfaces opposing to each other, an IC chip mounted on said first main surface of said package substrate, and an array of first signal electrodes formed on said second main surface of said package substrate; a mounting board having an array of second signal electrodes, each of said second electrodes being bonded onto a corresponding one of said first signal electrodes via a signal bump; and a dummy bump intervening between said package substrate and said mounting board, said dummy bump being fixed onto said package substrate and in contact with said mounting board without fixation thereon, wherein said mounting board further has a first insulating film which covers said mounting board with leaving at least a part of each of said second electrodes exposed, said first insulating film having a hole that exposes a portion of said mounting board, the dummy bump being in contact with said exposed portion of said mounting board such that said dummy bump is in direct contact with a surface of said mounting board and said dummy bump is allowed to slide directly on said surface of said mounting board.