A second wiring layer is connected to a first wiring layer via an insulating layer. The second wiring layer comprises pad structures. Each pad structure includes a first metal layer formed on the insulating layer, a second metal layer formed on the first metal layer, and a third metal layer formed on the second metal layer. The pad structures comprises a first pad structure and a second pad structure. A via-wiring diameter of the first pad structure is different from a via-wiring diameter of the second pad structure. A distance from an upper surface of the insulating layer to an upper surface of the second metal layer of the first pad structure is the same as a distance from the upper surface of the insulating layer to an upper surface of the second metal layer of the second pad structure.