Patent ID: 9515027
Filing Date: 2016-12-06
CPC Classification: H01L,H05K

Claim Text:
1. A printed circuit board comprising: a semiconductor device having a power source terminal and a ground terminal; and a printed wiring board on which the semiconductor device is mounted, wherein the printed wiring board comprises: a first wiring layer formed, as being a first surface layer of the printed wiring board, on which the semiconductor device is mounted; a second wiring layer having a first ground conductor plane to which the ground terminal is connected; a third wiring layer formed from at least one layer having a first power source conductor plane to which a direct power source voltage is applied, and a second power source conductor plane arranged so as to be arranged with a space from the first power source conductor plane in opposition to the first ground conductor plane, such that the second power source conductor plane and the first ground conductor plane form a planner capacitor; a fourth wiring layer formed on the printed wiring board at a second surface layer which is a back side surface of the first surface layer; and a capacitor element mounted on the fourth wiring layer, wherein a first terminal of the capacitor is electrically connected to the power source terminal and a second terminal of the capacitor is electrically connected to the ground terminal, wherein the power source terminal and the second power source conductor plane are connected through a first connecting conductor, the second power source conductor plane and the first power source conductor plane are connected through a second connecting conductor, the first terminal of the capacitor is electrically connected to the second connecting conductor, and the second terminal of the capacitor is electrically connected through a third connecting conductor to the first ground conductor plane, and the ground terminal is electrically connected through a fourth connecting conductor to the first ground conductor plane, and wherein: the first connecting conductor comprises a first via through which the first wiring layer and the second power source conductor plane are connected electrically, the second connecting conductor comprises a second via through which the fourth wiring layer and the second power source conductor plane are connected electrically, a third via through which the fourth wiring layer and the first power source conductor plane are connected electrically, and a wiring pattern formed on the fourth wiring layer for connecting the second via to the third via, the third connecting conductor comprises a fourth via through which the fourth wiring layer and the first ground conductor plane are connected electrically, and the fourth connecting conductor comprises a fifth via through which the first wiring layer and the first ground conductor plane are connected electrically.