Development of ultra-fine pitch ball bonding technology

While the environment surrounding wire bonding, i.e., wire, lead frame, wire bonder, and capillary, is being developed more eagerly than ever, wire bonding technology which can better meet the more compact and higher density chips without modifying the existing assembly process is desired. This paper discusses reduction of the diameter of a ball to be formed at the tip of the wire, the required wire diameter reduction, capillary tip diameter reduction, and attainment of a higher Young's modulus for the wire which can suppress wire sweep in transfer molding, and indicates that wire bonding for a pitch of 70 /spl mu/m or less can be performed with no problem in reliability of the bonded zone.