| 摘要 |
A BGA package primarily includes a leadless leadframe with a plurality of leads, a chip disposed on the leads, a die-attaching layer adhering to an active surface of the chip and the top surfaces of the leads, a plurality of bonding wires electrically connecting the chip to the leads, an encapsulant, and a plurality of solder balls. Each lead has a bottom surface including a wire-bonding area and a ball-placement area, moreover, a plurality of lips project from the bottom surfaces of the leads around the ball-placement areas. The encapsulant encapsulates the chip, the bonding wires, the die-attaching layer, and the top surfaces, the bottom surfaces except the ball-placement areas, and the laterals of the leads between the top surfaces and the bottom surfaces. A plurality of cavities are formed in the bottom of the encapsulant to expose the corresponding and embedded ball-placement areas. The lips have a plurality of internal sides exposed inside the cavities. The solder balls are disposed on the ball-placement areas and on the internal sides of the cavities to make the solder balls partially embedded in the corresponding cavities to offer non-planar ball pads. It is effective to resolve the solderability of the solder balls and to enhance the reliability of wire bonding and the stability of solder ball placement.
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