Structure of a ball bump for wire bonding and the formation thereof

Abstract

The ball bump mainly includes a body and a protrusion. The protrusion is located at the upper of the body and essentially consists of a flat upper surface with an annular inclination. The flat upper surface and the annular inclination together define the area for wire bonding. The method of the formation of the ball bump of wire bonding mainly comprises steps of: an end of a wire held by a bonding machine is melted to form a ball; the bonding machine bonds the ball onto the bonding pad to form a ball bump; the bonding tool moves upward a predetermined vertical distance and the clamp of the bonding tool is then opened; the bonding tool is moved a predetermined horizontal distance to reduce the connection part of wire connecting to the upper of the ball bump for the convenience of wire cutting, and this forms a protrusion on the ball bump consisting of a flat upper surface with an annular inclination; the bonding tool is again moved upward a predetermined vertical distance, and the clamp releases the wire for the ball bump process which follows; the clamp is closed to hold the wire and is moved upward to pull the wire, and the wire is cut along the heat affected zone and leaves a smaller tip on the ball bump.

Dependencies are inferred from the claim text.