Method of fabricating chip package structure

A method of fabricating a chip package structure, comprising:

• providing a lead frame having an upper surface and a lower surface, wherein the lead frame comprises a die pad, a plurality of leads surrounding the die pad, and at least a structure enhancement element connecting the die pad to one of the leads, or connecting two of the adjacent leads;
• providing a chip having an active surface, a back surface, and a plurality of chip bonding pads disposed on the active surface;
• adhering the back surface of the chip to the die pad;
• forming a plurality of bonding wires so as to electrically connect the chip bonding pads and the leads, respectively;
• forming an upper encapsulant and a lower encapsulant, wherein the upper encapsulant encapsulates the upper surface of the lead frame, the chip and the bonding wires, while the lower encapsulant encapsulates the lower surface of the lead frame and has at least a concave so as to expose the structure enhancement element;
• and
• etching the structure enhancement element with use of the lower encapsulant as an etching mask until the die pad and one of the leads connected by the structure enhancement element or two of the adjacent leads connected thereby are electrically insulated.