Disclosed is a method for fabricating a semiconductor package, including providing a package unit having an insulating layer and at least a semiconductor element embedded into the insulating layer, wherein the semiconductor element is exposed from the insulting layer and a plurality of recessed portions formed in the insulating layer; and electrically connecting a redistribution structure to the semiconductor element. The formation of the recessed portions release the stress of the insulating layer and prevent warpage of the insulating layer from taking place.