A fabricating method of a semiconductor device, in which a first semiconductor chip having a desired first thickness and a semiconductor chip having a desired second thickness are used to fabricate a semiconductor device having a desired third thickness that is greater than the sum of the first and second thicknesses includes providing the first semiconductor chip, which has the first thickness, forming the second semiconductor chip, which is connected to the first semiconductor chip via through silicon vias (TSVs) and has the second thickness, on the first semiconductor chip, and providing a dummy semiconductor chip, which is not electrically connected to the semiconductor chip and has a fourth thickness, on the second semiconductor chip, wherein the fourth thickness is generated based on a difference between about the third thickness and about a sum of the first and second thicknesses.