A method of fabricating a semiconductor device is provided. The method may include forming an insulating layer on a wafer. The wafer may have an active surface and an inactive surface which face each other, and the insulating layer may be formed on the active surface. A pad may be formed on the insulating layer, and a first hole may be formed in the insulating layer. A first hole insulating layer may then be formed on an inner wall of the first hole. A second hole may be formed under the first hole. The second hole may be formed to extend from the first hole into the wafer. A second hole insulating layer may be formed on an inner wall of the second hole. The semiconductor device fabricated according to the method may also be provided.