A method of manufacturing a circuit board includes: providing a substrate including a bottom layer and a resin layer over the bottom layer, the resin layer including a first surface in contact with the bottom layer and a second surface opposite to the first surface; forming a plurality of vias through the resin layer; depositing a first metal layer in the vias, the first metal layer filling a portion of each of the vias; depositing a second metal layer over the first metal layer and in the vias; forming a patterned metal layer over the second metal layer and extending from each of the vias to a position over the second surface; separating the bottom layer and the resin layer; and removing a portion of the resin layer from the first surface, so that the first metal layer protrudes from the resin layer.