SEMICONDUCTOR PACKAGE

PROBLEM TO BE SOLVED: To provide a semiconductor package which can match the impedance over the entire transmission path. SOLUTION: The semiconductor package is provided with a metal plate 12, and a signal wiring layer 20 formed on one surface of an insulating substrate 16. The other surface of the insulating substrate 16 contains a wiring substrate 10 fixed on the metal plate 12. The signal wiring layer 20 is constituted of a wiring line portion 20a and a connecting pad portion 20b having a wider width than that of the line portion. The part of the metal plate 12 corresponding to the connecting pad portion 20b is provided with a recess 12a. The electrostatic capacity constituted between the wiring line portion 20a and the metal plate 12 and that between the connecting pad portion 20b and the metal plate 12 are set equal. COPYRIGHT: (C)2008,JPO&INPIT