Method for packaging a power device with bottom source electrode

A method for packaging a power device with bottom source electrode comprising:

• providing a lead frame unit comprising a first base and a second base separated from each other, a third base and a fourth base respectively located at two opposite sides of the first base;
• 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 positioned and trapped into a groove formed on the top surface of the third base and a groove formed on the top surface of the fourth base, and a bottom metal layer formed on the back surface of the primary packaging structure is attached to the 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 the bottom surfaces of the first base, the third base and the fourth base are exposed through the plastic packaging body.