US Patent 7660130 Semiconductor device

A semiconductor device includes: a wiring substrate including multiple connection pads provided on a top surface thereof and multiple lands that are provided on a bottom surface thereof and electrically connected to the corresponding connection pads; a semiconductor chip mounted on the top surface of the wiring substrate and electrically connected to the connection pads; a solder resist deposited on the bottom surface of the wiring substrate and having multiple openings to which the lands are respectively exposed, each of the openings being shifted with respect to a corresponding land of the lands; multiple external terminals connected respectively to the lands through the openings; and a dummy wiring arranged on the bottom surface of the wiring substrate and separately from the corresponding land so that a corresponding external terminal of the external terminals is connected to the corresponding land and the dummy wiring partially exposed to the corresponding opening.