The Development of Copper Wire Bonding for Plastic Molded Semiconductor Packages

Abstract

Gold wire bonding has been employed in mass production process of semiconductors because the ball bonding system using gold wire can be very effectively utilized on the aspect of productivity. There is, however, an increasing demand for development of a new technology to replace gold wire with other materials in the light of further enhancing the reliability of devices and saving the material cost. In this background, the authors developed the copper wire bonding technology for plastic molded semiconductor, fundamentally on the basis of employing the hardware system for conventional gold wire bonding, Primarily, the ball formatio technology and ball bonding technology were major subjects of development. These two problems were successfully solved by the development of power source for S.P. discharge, use of hot capillary tip, control of physical properties of aluminum pad, and other techniques.
Furthermore, as a result of steady and versatile fundamental researches and applied studies such as material development, process engineering development, quality assurance and hardware development, the practicability of copper wire bonding has been confirmed. This paper mainly refers to the studies of its process.