A semiconductor structure includes a semiconductor substrate, a dielectric layer, a buffer layer, at least one recess, and at least one conductor. The dielectric layer is present on the semiconductor substrate. The buffer layer is present between the semiconductor substrate and the dielectric layer. The recess extends into the semiconductor substrate through the dielectric layer and the buffer layer, in which the buffer layer has a removing rate with respect to an etching process for forming the recess. The removing rate of the buffer layer is between those of the semiconductor substrate and the dielectric layer. The conductor is present in the recess.