Circuit board, a method for manufacturing same, and a method of electroless plating

The present invention relates to a novel circuit board, whereon semiconductors and the like are mounted, and a method of manufacturing the same; and more particularly, the invention relates to a circuit board having via-holes filled with metal for connecting interlayer conductor wiring, and a method of manufacturing the same. A circuit board is provided, wherein electroless plating to fill via-holes can be controlled uniformly with desirable reproducibility, and via-hole portions can be identified from the surface of the substrate after forming a second conductor thereon. The specific circuit board is obtained by applying a potential higher then the potential of the electroless plating to the conductor on the surface when filling the via-holes by electroless plating. In the circuit board, via-hole portions can be identified optically, because the via-hole portion differs from the second conductor in surface condition, such as when a dent is formed.