| abstract |
A lead frame, for a plastic molded type semiconductor package, comprises a plurality of leads and a die pad surrounded by the leads wherein a surface of the die pad is adapted for mounting a semiconductor chip. Areas on the leads adapted for wire bonding are plated with at least one noble metal. The lead frame is characterized in that the at least one noble metal is plated on the surface of die pad in a manner that a central region as well as at least a portion of the brim region of the die pad are kept un-plated. In the lead frame of the present invention, bare copper surface on the un-plated region of the die pad provides improved adhesion to molding compound thereby enhancing the reliability of the finished package. The lead frame may be further provided with a rectangular groove, cavities, mesh-type notches, or through-holes formed in the un-plated brim region of the die pad thereby providing mechanical interlock mechanism to strengthen the bonding between the die pad and the package body. |