Patent ID: 7326640

Claim:
A method of realizing thermosonic wire bonding between metal wires and copper pads by depositing a thin metal film to a surface of a semiconductor wafer with copper pads, wherein the thin metal film deposited on the surface of the semiconductor wafer is to ensure a perfect bonding and sufficient bonding strength between the metal wires and the copper pads after being subjected to the thermosonic wire bonding process, the method comprises the steps of: depositing another thin metal film of an appropriate thickness to the surface of the wafer with the copper pads, where the thin metal film is deposited onto copper pads of the wafer to act as a protective film; subjecting the wafer with copper pads to die sawing and die bonding under an atmospheric surrounding to form a plurality chips with copper pads, where an oxide film is only formed on the thin metal film to prevent oxidation from occurring in the copper pads located thereunder; removing the oxide of the thin metal film and the other thin metal film by ultrasonic power generated by a thermosonic wire bonder such that the metal wires may be bonded to the clean surfaces of copper pads; whereby the packaging process of the chips with copper pads deposited with the thin metal film is completely identical to that adopted in chips with aluminium pads without altering the conventional process or equipments.