The present disclosure provides a method for manufacturing a semiconductor package. The method includes (1) determining a die warpage value under a predetermined temperature range; (2) determining a difference between a density of a top metal and a density of a bottom metal of a substrate according to the die warpage value; and (3) joining the die and the substrate under the predetermined temperature range. The top metal includes all metal layers overlying a middle layer, and the bottom metal includes all metal layers underlying the middle layer. The middle layer includes a core or a metal layer.