Method for making a semiconductor package with the distance between a lead frame die pad and heat spreader determined by the thickness of an intermediary insulating sheet

摘要

A lead frame and die sub-assembly is first manufactured by a conventional method including bonding a die to the die attach pad of a lead frame and connecting wires between the die and the lead frame fingers. The sub-assembly is stacked first adjacent a dielectric plastic sheet that is in turn stacked against a metal heat spreader block. The dielectric sheet has a centrally located hole registered with the die attach pad. A dollop of an uncured resin is dispensed in the gap between the die attach pad and block. This assembly is compressed between two hot platens whereby the lead fingers, dielectric sheet and the block are bonded together and the resin dollop is flattened to a controlled thickness, namely the thickness of the dielectric sheet. The thickness of the dielectric sheet controls the flattened thickness of the cured resin dollop. After the platens are withdrawn, the local portion of the lead frame having been bonded in the stack is then put into a mold and the stack assembly encapsulated in a thermosetting resin to produce the semiconductor package.