Conductive structures and method of manufacture thereof are disclosed. In some embodiments, a method of forming a conductive structure includes providing a substrate having a recess formed therein, the recess lined with a first seed layer and partially filled with a first conductive material; removing a portion of the first seed layer free from the first conductive material to form an exposed surface of the recess; lining the exposed surface of the recess with a second seed layer; and filling the recess with a second conductive material, the second conductive material covering the first conductive material and the second seed layer.