Analysis of promising copper wire bonding in assembly consideration

Abstract

Although gold wire proposes the good characteristics such as malleability and stabilization, in the cost consideration to promote the package competition, the copper wire provides the better attraction. Therefore, the assembly houses gradually impress on the copper wire bonding technology desirably replacing the traditional gold wire bonding, especially in high-pin-count package. Besides the cost superiority, the electrical resistivity of copper, 1.7 µΩ-cm, is lower than that of gold, 2.2 µΩ-cm, and aluminum, 2.65 µΩ-cm. Furthermore, the mechanical characteristics of copper, such as Youngs modulus and rigidity modulus (130 GPa and 48 GPa, respectively), are larger than those of gold (78 GPa and 27 GPa, respectively). In copper wire bonding, the wire ball on pad demonstrates the excellent neck intensity and the arc shape of the copper wire is more stable. This superiority in molding process is singularly and significantly noticeable.