Patent ID: 6924987

Claim:
A wiring board comprising: a first insulating layer; a first conductor layer provided on the surface of the first insulating layer; a second conductor layer provided on the first insulating layer in its surface remote from the first conductor layer; and a third conductor layer provided through a second insulating layer on the second conductor layer provided on the first insulating layer, wherein conductor wirings to be connected to a semiconductor chip in its external terminal (bonding pad) are provided in the first conductor layer, only a conductor pattern connected through a via to a ground wiring, for supplying a power supply of ground potential to the semiconductor chip, among the conductor wirings provided in the first conductor layer is provided in the second conductor layer, a power supply terminal connected through a via to a power supply wiring, for supplying an operation power supply of a potential other than the ground potential to the semiconductor chip, among the conductor wirings provided in the first conductor layer, a signal terminal connected through a via to a signal wiring for transmitting an electric signal, and a ground terminal connected through a via to the conductor pattern in the second conductor layer are provided in the third conductor layer, and the conductor pattern provided in the second conductor layer is spread over the whole region except for the circumference of the via for connecting the power supply wiring to the power supply terminal and the via for connecting the signal wiring to the signal terminal.