Patent ID: 8247272

Claim:
A method of forming a device comprising: providing first and second contact regions of the device, wherein the first contact region comprises copper coated with an OSP material; forming a ball bump on the first contact region, wherein forming the ball bump comprises threading a wire through a capillary of a bonding tool, wherein a tip of the wire is disposed beyond a tip of the capillary, disposing the capillary in a forming chamber with a forming gas, and forming a spark in the chamber to form the ball bump on the tip of the wire, smoothing the ball bump to form a flat top surface on the ball bump that is devoid of a tail, wherein smoothing the ball bump comprises locating the capillary with the ball bump on the first contact region, processing to form a ball bump which penetrates the OSP material and is sufficiently bonded to the first contact region, translating the capillary in a first direction away from the ball bump, and translating the capillary in a second direction back across the ball bump to form the flat top surface, wherein the translations are along the same angle as the flat surface; bonding a first end of the wire to the second contact region; and bonding a second end of the wire to the top surface of the ball bump.