An ultra-thin semiconductor package includes a lead frame having a die pad and a plurality of leads surrounding the die pad. The die pad includes a chip attaching part to which a semiconductor chip is attached and a peripheral part integral with and surrounding the chip attaching part. The thickness of the chip attaching part is smaller than the thickness of the leads. The package device further includes bonding wires electrically connecting the chip to the leads, and a package body for encapsulating the semiconductor chip, bonding wires, die pad, and inner portions of the leads. A first thickness of the die pad is preferably between about 30-50% of a second thickness of the leads. An overall thickness of the package device is preferably equal to or less than 0.7 mm.