Image Number 2 for United States Patent #6433420.
A BGA semiconductor package having an embedded heat sink is proposed. The heat sink mounted on a substrate includes a flat portion and supporting members for supporting the flat portion to be positioned above a semiconductor chip. The flat portion is formed with at least one taper air vent for ventilating air in a gap between the flat portion and the chip during a molding process. This further helps prevent voids from forming in an encapsulant due to the air trapped in a molding resin as being flowing slowly through the gap, and avoid the occurrence of a popcorn effect on the encapsulant during a temperature cycle in subsequent processes. As a result, quality and yield for the packaged products can be significantly improved.