A semiconductor device includes a wiring substrate having an upper surface, a semiconductor chip mounted on the wiring substrate, and a stiffener ring fixed onto the wiring substrate via a plurality of adhesive layers. The upper surface is a quadrangular shape, and first and second center lines and first and second diagonal lines can be drawn. The stiffener ring has four extension portions and four corner portions. Adhesive layers include first, second, third and fourth adhesive layers that respectively overlap with the four extension portions and that are arranged at a portion overlapping with one of the first center line and the second center line. Also the adhesive layers include fifth, sixth, seventh, and eighth adhesive layers that respectively overlap with the four corner portions and that are arranged at a portion overlapping with one of the first diagonal line and the second diagonal line.

A method for fabricating a package structure is provided. The method includes forming a metal layer over a carrier substrate. The method includes forming a dielectric layer over the metal layer. The method includes forming a plurality of first openings in the dielectric layer. The method includes forming a plurality of second openings in the dielectric layer. The first openings and the second openings expose the metal layer. The method includes forming a conductive material in the first openings and the second openings to form a plurality of conductive features. The method includes removing the metal layer and the carrier substrate. The method includes thinning the dielectric layer around the conductive features. The method also includes bonding a package component to the conductive features.