A method of fabricating a substrate having a through via includes: providing a carrier board having a release layer thereon; attaching the substrate onto the carrier board via the release layer; applying a light beam to the substrate to form a first blind hole in the substrate, wherein the first blind hole penetrates a first surface and a second surface of the substrate; performing an enlargement process on the first blind hole to form a second blind hole; forming a through via in the second blind hole; and performing a de-bonding process to release the substrate having a through via from the carrier board.