Patent ID: 7659193

Claim:
A fabrication method of conductive structures for electrically conductive pads of a circuit board, comprising the steps of: providing a circuit board with a plurality of first and second electrically conductive pads on a first surface thereof and a plurality of third electrically conductive pads on a second surface thereof, and respectively forming a first insulating protection layer and a second insulating protection layer on the first and second surfaces of the circuit board, the first and second insulating protection layers having formed therein a plurality of openings for exposing the first, second and third electrically conductive pads; forming a first conductive layer on the first insulating protection layer and in the openings of the first insulating protection layer, and forming a second conductive layer on the second insulating protection layer and in the openings of the second insulating protection layer; respectively forming a first resist layer and a second resist layer on surfaces of the first and second conductive layers, the first and second resist layers having a plurality of openings so as to respectively expose the first and second conductive layers on surfaces of the first, second and third electrically conductive pads; electroplating an electroplated metal layer on surfaces of the first and second conductive layers on the first, second and third electrically conductive pads exposed from the openings of the first and second resist layers; electroplating a first electroplated connecting layer on the surface of the electroplated metal layer; respectively forming a third resist layer and a fourth resist layer on surfaces of the first and second resist layers to cover the first and third electrically conductive pads, and forming a plurality of openings in the third resist layer so as to expose the first electroplated connecting layer on the second electrically conductive pads; and electroplating a second electroplated connecting layer on the first electroplated connecting layer on the second electrically conductive pads.