A stacked structure includes a circuit board, an electronic component, metallic cores, and insulating cladding layers. The circuit board includes first bonding pads. The electronic component includes second bonding pads that are opposite to the first bonding pads. Each metallic core is connected to a corresponding first bonding pad and a corresponding second bonding pad. The metallic cores have a curved surface interposed between the corresponding first bonding pad and the corresponding second bonding pad. The insulating cladding layers are separated from each other and cover the curved surfaces of the metallic cores.