Abstract: A circuit board, comprising a multi-layer circuit board, a first conductive circuit, a first circuit layer, an adhesion promoter layer, a second conductive circuit, and a second circuit layer. The multi-layer circuit board comprises an inner circuit and an opening. The opening exposes the inner circuit. The first conductive circuit is disposed in the opening and on the inner circuit. The first circuit layer is disposed on the first conductive circuit in the opening and lower than the depth of the opening. The adhesion promoter layer is disposed in the opening and on the surface of the multi-layer circuit board and connected to the first conductive circuit. The second conductive circuit is disposed on the adhesion promoter layer and on the first circuit layer in the opening. The second circuit layer is disposed on the second conductive circuit in the opening and on the second conductive circuit.

Abstract: The present disclosure provides a circuit board including a first circuit layer, a dielectric layer on the first circuit layer, and a seed layer on the dielectric layer and directly contacting the first circuit layer, in which a top surface of the seed layer includes a levelled portion. The circuit board also includes a second circuit layer on the levelled portion of the seed layer, in which a grain boundary density of the second circuit layer is lower than that of a portion of the seed layer directly contacting the first circuit layer.

Abstract: The invention discloses a method of improving a wire structure of a circuit board, comprising the following steps: providing a multi-layer circuit board, including an inner circuit and a surface circuit; forming an opening to expose the inner circuit; forming a first circuit layer in the opening; removing the first circuit layer, the first conductive circuit, and the surface circuit on the multi-layer circuit board and removing a part of the first circuit layer in the opening; forming an adhesion promoter layer in the opening and on the multi-layer circuit board; forming a second conductive circuit on the adhesion promoter layer and on the first conductive circuit layer in the opening; forming a photoresist layer on the second conductive circuit layer; forming a second circuit layer in the opening and on the multi-layer circuit board, and removing the photoresist layer and a part of the second conductive circuit.