Printed wiring board and method of suppressing power supply noise thereof

Abstract

Disclosed is a printed wiring board having signal layers each interposed between a power supply layer and a ground layer, wherein the signal layer includes at least one of a wiring region for a ground potential and a wiring region for a power supply potential.

1 . A printed wiring board including at least one of a wiring region for a power supply potential and a wiring region for a ground potential in a predetermined free area provided on a signal layer thereof. 
     
     
         2 . The printed wiring board according to  claim 1 , wherein the signal layer is interposed between a power supply layer and a ground layer through respective insulating layers. 
     
     
         3 . The printed wiring board according to  claim 2 , comprising:
 a first power supply layer, a first signal layer, a first ground layer, a second power supply layer, a second signal layer, and a second ground layer, laminated one atop another in order, through the respective insulating layers; wherein said first signal layer includes a first wiring region for one of the power supply potential and the ground potential in the free area provided on said first signal layer; and   said second signal layer includes a second wiring region for the other of the power supply potential and the ground potential in the free area provided on said second signal layer.   
     
     
         4 . The printed wiring board according to  claim 2 , wherein at least one part region of the signal layer immediately below a semiconductor device mounted on said printed wiring board is set to the free area, said one part region of the signal layer including at least one of a wiring region for the power supply potential and a wiring region for the ground potential. 
     
     
         5 . The printed wiring board according to  claim 2 , wherein a region on the signal layer corresponding to a region extended in four directions from a bottom center portion of a semiconductor device mounted on said printed wiring board is set to the free area which includes at least one of the wiring region for the power supply potential and the wiring region for the ground potential. 
     
     
         6 . The printed wiring board according to  claim 5 , wherein the semiconductor device including a plurality of electrodes is mounted on a bottom surface facing a component surface of said printed wiring board;
 said component surface of said printed wiring board includes a plurality of pads for being connected with said electrodes of the semiconductor device, respectively, and through holes connected to said pads, respectively, are arranged in a periphery side of the semiconductor device with respect to said pads; and   the region on the signal layer corresponding to the region extended in the form of a cross corresponding to vertical and horizontal center lines of said bottom surface of the semiconductor device is set to the free area.   
     
     
         7 . The printed wiring board according to  claim 5 , wherein the free area has a shape in which a width thereof is reduced, in incremental steps, from a center portion of the bottom surface of the semiconductor device toward the periphery side of the semiconductor device. 
     
     
         8 . The printed wiring board according to  claim 3 , wherein said first wiring region is connected to a through hole for the one of the power supply potential and the ground potential, disposed in the vicinity of said first wiring region; and
 said second wiring region is connected to a through hole for the other of the power supply potential and the ground potential, disposed in the vicinity of said second wiring region.   
     
     
         9 . A printed wiring board including at least one of a wiring region for a power supply potential and a wiring region for a ground potential in a free area of at least one of a component surface thereof and a soldering surface thereof. 
     
     
         10 . The printed wiring board according to  claim 9 , wherein at least one part region of said component surface immediately under a semiconductor device mounted on said printed wiring board is set to said free area. 
     
     
         11 - 16 . (canceled)