| 摘要 |
PURPOSE:To shorten a distance up to a signal wiring from a grounding layer, and to reduce the inductance of the signal wiring by forming a conductive layer used as the grounding layer to the upper surface section of a wiring substrate and shaping the signal wiring onto the conductive layer. CONSTITUTION:A conductive layer 6 is employed for constituting a grounding layer for a microstrip line, and formed onto a wiring substrate 4 to a latticed shape. A second layer conductive layer 10 extended and formed on an insulating film 9 in the upper section of the conductive layer 6 is used as a signal wiring for electrically connecting each chip 7 mutually. The conductor layers 6, 10 and the insulating film 9 constitute a microstrip, a distance between the conductive layer 6 and the conductive layer 10 takes a value sufficiently smaller than the line width of the conductive layer 10, and the inductance of the conductive layer 10 takes an enough small value. Accordingly, the speed of an electric signal flowing through the conductive layer 10 can be increased. |
