The chip package includes a first and second semiconductor chip. The first semiconductor chip has a first connection structure that electrically connects to a bond pad on a first surface of the first semiconductor chip. The second semiconductor chip has a second connection structure. The second connection structure is electrically connected to a bond pad on a first surface of the second semiconductor chip and extends through the second semiconductor chip to a second surface of the second semiconductor chip. A portion of the second connection structure extending to the second surface of the second semiconductor chip is electrically connected to the first connection structure and formed of a harder material than the first connection structure.