The invention provides a semiconductor package, which comprises a semiconductor chip having an active surface with a conductive pad thereon; an electroplated Au-Sn alloy bump over the active surface; and a (glass) substrate comprising conductive traces electrically coupling with the electroplated Au-Sn alloy bump, wherein the electroplated Au-Sn alloy bump has a composition from about Au0.85Sn0.15 to about Au0.75Sn0.25 in weight percent uniformly distributed from an end in proximity to the active surface to an end in proximity to the substrate. The invention further provides a method of manufacturing a semiconductor package, the method comprising forming patterns of conductive pads on an active surface of a semiconductor chip; electroplating Au-Sn alloy bump over the conductive pads; and bonding the semiconductor chip on a corresponding conductive trace on a substrate by a reflow operation or a thermal press operation.