US Patent 7183134 Ultrathin leadframe BGA circuit package

A circuit package is formed using a leadframe. The leadframe is formed or etched to align a plurality of bond pad structures above a reference plane while supporting leadframe fingers are positioned below the reference plane. Jumper wires are wirebonded between terminals on the die and the bond pads to form a package subassembly. The subassembly is encapsulated and then background to remove the leadframe fingers and surrounding frame. The bond pads which remain embedded in the encapsulation material are exposed on the lower surface of the package for connection to further conductors.