Patent ID: 7220607

Claim:
A method of manufacturing a semiconductor device, comprising the steps of: (a) providing a lead frame, the lead frame having chip mounting portions, suspending leads connected to the chip mounting portions, a plurality of leads arranged around each of the chip mounting portions, through holes formed outside the suspending leads in extending directions of the suspending leads, and first trenches formed along the suspending leads on a back surface side opposite to the chip mounting portion side so as to communicate with the through holes; (b) mounting semiconductor chips respectively over the chip mounting portions; (c) connecting electrodes of the semiconductor chips and the leads with each other through electrically conductive wires; (d) disposing the lead frame over a die surface of a resin molding die, thereafter making air vents formed in the resin molding die and the through holes and the first trenches formed in the lead frame correspond to each other, clamping the resin molding die, then injecting sealing resin into cavities of the resin molding die, allowing air which has entered the through holes to flow out of the through holes by virtue of an influent pressure of the sealing resin from the air vents and the first trenches, and performing resin sealing so that the sealing resin is injected into the cavities and the through holes; (e) after the resin sealing, allowing the sealing resin to remain in the through holes of the lead frame and releasing the resin molding die; and (f) separating the leads and the suspending leads from the lead frame to divide the lead frame into the individual chip mounting portions.