A solar cell includes a substrate of a first conductive type having at least one via hole; an emitter layer of a second conductive type opposite to the first conductive type; and at least one first electrode positioned from a first surface of the substrate to the at least one via hole, and at least one first electrode current collector positioned from the at least one via hole to a second surface of the substrate, wherein the at least one via hole has a radius of about 10 μm to about 40 μm, and at least one of a portion of the at least one first electrode and a portion of the at least one electrode current collector, in the at least one via hole, includes at least one cavity.