Lead-frame forming for improved thermal performance

摘要

A lead frame of a plastic integrated circuit package is fabricated in two steps. First, from a rectangular sheet of metal, lead fingers of the lead frame are formed. Second, the die pad of the lead frame is clamped and is simultaneously separated and downset from the lead fingers of the lead frame by shearing the lead frame with a mated punch die pair. Performing the separation and downset of the die pad from the lead fingers results in essentially no horizontal gap between the lead fingers and the die pad. The downset of the die pad with respect to the lead fingers results in a vertical separation between the die pad and the lead fingers.