A semiconductor structure is disclosed. The semiconductor structure includes: a semiconductor substrate having a front surface and a back surface facing opposite to the front surface; a filling material extending from the front surface into the semiconductor substrate without penetrating through the semiconductor substrate, the filling material including an upper portion and a lower portion, the upper portion being in contact with the semiconductor substrate; and an epitaxial layer lined between the lower portion of the filling material and the semiconductor substrate. An associated manufacturing method is also disclosed.