1. Field of the Invention
The present invention related to a wiring board with built-in capacitors. Specifically, the invention relates to a wiring board with built-in capacitors, which has a multilayer wiring structure and capable of mounting an IC chip thereon.
2. Description of the Prior Art
In a proposed wiring board on which an IC chip can be mounted, a thin film capacitor is connected between a power line and a ground line of the IC chip to realize decoupling and restrain instantaneous lowering of the potential of the power line due to switching noise resulting from high-speed ON/OFF of the mounted IC chip. For example, in a substrate disclosed in Patent Document 1 (JP 2005-191266 A), a plurality of capacitors which are differing in dielectric film thickness are connected in parallel between a power line and a ground line of an IC chip to reduce the impedance across a wider range of frequencies in comparison to a substrate using a single capacitor.