Wiring board, semiconductor device, electronic device, and circuit board for electronic parts

#The present invention relates to a wiring board, a semiconductor device, and an electronic device, and particularly to a technology by which reduction in an inductance of a wiring section in a wiring board for mounting on a semiconductor device or that of a wiring section composed of leads in a package of such semiconductor device as well as reduction in inductive cross talk noise can be achieved.

#Furthermore, the invention relates to a circuit board for electronic parts, and particularly to a circuit board for electronic parts by which its characteristic impedance can easily be adjusted.

#In also the world of digital circuits, trends of speeding up operations proceed, so that there were the cases wherein, for example, operation characteristics of a semiconductor chip to be mounted are affected by a finished state of a board circuit as in the world of analog circuits. Characteristic impedance of line (wiring) is decided by a type of materials, a distance of an insulating material to be inserted between the board and a plate-like ground layer, or a pitch defined between leads and the like. In this respect, since such board circuit is fabricated in a dimension region which is close to the limit of the present manufacturing engineering, it can be made clear for the first time whether or not the resulting board circuit is the one which is suited for operation characteristics of a semiconductor chip to be mounted after having been finished. In the world of analog circuits, matching work is conducted to readjust a joined position of parts while confirming operation characteristics of a semiconductor chip, whereby adjustment has been performed.

#The present invention will be explained in more detail in conjunction with appended drawings, wherein:

#FIG. 1 is a schematic planar view showing an outlined structure of a printed wiring board according to the first preferred embodiment of the present invention;

#FIG. 2 is a view for explaining action of the printed wiring board according to the first preferred embodiment;

#The invention will be described in detail hereinafter in conjunction with preferred embodiments by referring to the accompanying drawings.

#(The First Preferred Embodiment)

#FIG. 1 is a schematic diagram showing an outlined constitution of a printed wiring board according to the first preferred embodiment of the invention wherein reference numeral 11 designates an insulation board, 12 signal leads, 13 a control lead, 14 a power-source lead (Vdd), 15 a ground (GND) lead, 16 an insulating film (polyimide), and 17 an electromagnetic shielding film (metallic foil), respectively.