| 主权项 |
1. A method for packaging a power device with a bottom source electrode, the method comprising the steps of:
providing a lead frame unit comprising a first base, a second base, a third base, and a fourth base, wherein the second base is separated from the first base, wherein the third base and the fourth base are respectively located near two opposite sides of the first base; wherein the third base and the fourth base are symmetric with respect to a line of symmetry; wherein the first and second bases are positioned on the line of symmetry; and wherein the third and fourth bases are not positioned on the line of symmetry; forming, flipping and attaching a primary packaging structure onto the first base and the second base, wherein a plurality of solder bumps are pre-formed on a front surface of the primary packaging structure and are respectively pre-attached to the first base and the second base; attaching a bridge-shaped metal clip atop the primary packaging structure, wherein the bridge-shaped metal clip comprises a top metal portion and side metal portions connected to two opposite sides of the top metal portion and bent downwards, wherein the side metal portions are respectively positioned and trapped into a groove formed on a top surface of the third base and a groove formed on a top surface of the fourth base, and wherein a bottom metal layer formed on a back surface of the primary packaging structure is attached to a bottom surface of the top metal portion through a conductive material; and forming a plastic packaging body encapsulating the lead frame unit, the primary packaging structure and the bridge-shaped metal clip, wherein bottom surfaces of the first base, the third base and the fourth base are exposed from the plastic packaging body. |
