Methods for moding a leadframe in plastic integrated circuit devices

Abstract

Methods for making packages and leadframes are enclosed. The package includes a die, a die pad, leads, bond wires, and an encapsulant. The lower surfaces of the die pad and leads are provided with a stepped profile by an etching step that etches partially through the thickness of a peripheral portion of the die pad, and also etches partially through the thickness of portions of the leads. Encapsulant material is applied by molding or liquid encapsulation techniques. The encapsulant material fills in beneath the recessed, substantially horizontal surfaces of the die pad and leads formed by the above-described partial etching step, and thereby prevents the die pad and leads from being pulled vertically from the package body. Other surface of the die pad and leads are not covered during the encapsulation step, but rather remain exposed at the lower surface of the package for connecting the package externally. After encapsulation, the die pad and leads are severed from the leadframe, and a completed package is cut from the leadframe. Packages may be cut from the leadframe with a punch or saw. A portion of the severed leads may be bent upwards at an oblique angle to facilitate connection of a solder interconnection to the package. The packages may be made one at a time, or a plurality of packages may be made simultaneously.