A method of manufacturing a through silicon via (TSV) is provided in the present invention, including steps of forming a TSV sacrificial structure in a substrate, wherein the TSV sacrificial structure contacts a metal interconnect on the front side of the substrate, performing a backside thinning process to expose the TSV sacrificial structure from the back side of the substrate, removing the TSV sacrificial structure to form a through silicon hole, and filling the through silicon hole with conductive material to form a TSV.