Abstract: A Quad Flat No-Lead (QFN) semiconductor package includes a die pad; I/O connections disposed at the periphery of the die pad; a chip mounted on the die pad; bonding wires; an encapsulant for encapsulating the die pad, the I/O connections, the chip and the bonding wires while exposing the bottom surfaces of the die pad and the I/O connections; a surface layer formed on the bottoms surfaces of the die pad and the I/O connections; a dielectric layer formed on the bottom surfaces of the encapsulant and the surface layer and having openings for exposing the surface layer. The surface layer has good bonding with the dielectric layer that helps to prevent solder material in a reflow process from permeating into the die pad and prevent solder extrusion on the interface of the I/O connections and the dielectric layer, thereby increasing product yield.

Abstract: A Quad Flat No-Lead (QFN) semiconductor package includes a die pad; I/O connections disposed at the periphery of the die pad; a chip mounted on the die pad; bonding wires; an encapsulant for encapsulating the die pad, the I/O connections, the chip and the bonding wires while exposing the bottom surfaces of the die pad and the I/O connections; a surface layer formed on the bottoms surfaces of the die pad and the I/O connections; a dielectric layer formed on the bottom surfaces of the encapsulant and the surface layer and having openings for exposing the surface layer. The surface layer has good bonding with the dielectric layer that helps to prevent solder material in a reflow process from permeating into the die pad and prevent solder extrusion on the interface of the I/O connections and the dielectric layer, thereby increasing product yield.

Abstract: A Quad Flat No-Lead (QFN) semiconductor package includes a die pad; I/O connections disposed at the periphery of the die pad; a chip mounted on the die pad; bonding wires; an encapsulant for encapsulating the die pad, the I/O connections, the chip and the bonding wires while exposing the bottom surfaces of the die pad and the I/O connections; a surface layer formed on the bottoms surfaces of the die pad and the I/O connections; a dielectric layer formed on the bottom surfaces of the encapsulant and the surface layer and having openings for exposing the surface layer. The surface layer has good bonding with the dielectric layer that helps to prevent solder material in a reflow process from permeating into the die pad and prevent solder extrusion on the interface of the I/O connections and the dielectric layer, thereby increasing product yield.

Abstract: A Quad Flat No-Lead (QFN) semiconductor package includes a die pad; I/O connections disposed at the periphery of the die pad; a chip mounted on the die pad; bonding wires; an encapsulant for encapsulating the die pad, the I/O connections, the chip and the bonding wires while exposing the bottom surfaces of the die pad and the I/O connections; a surface layer formed on the bottoms surfaces of the die pad and the I/O connections; a dielectric layer formed on the bottom surfaces of the encapsulant and the surface layer and having openings for exposing the surface layer. The surface layer has good bonding with the dielectric layer that helps to prevent solder material in a reflow process from permeating into the die pad and prevent solder extrusion on the interface of the I/O connections and the dielectric layer, thereby increasing product yield.

Abstract: A QFN package includes a chip-mounting base; electrically connecting pads disposed around the periphery of the chip-mounting base, the bottom surfaces of the chip-mounting base and the electrically connecting pads being covered by a copper layer; a chip mounted on the top surface of the chip-mounting base; bonding wires electrically connecting to the chip and the electrically connecting pads; an encapsulant encapsulating the chip-mounting base, the electrically connecting pads, the chip and the bonding wires while exposing the copper layer; and a dielectric layer formed on the bottom surfaces of the encapsulant and the copper layer and having a plurality of openings exposing a portion of the copper layer. The copper layer has good bonding with the dielectric layer that helps to prevent solder material in a reflow process from permeating into the interface between the chip-mounting base, the electrically connecting pads and the dielectric layer, thereby avoiding solder extrusion and enhancing product yield.