Eutectic bonding of copper to ceramics for thermal dissipation applications – A review

Metallic copper, which has low electrical resistivity and high thermal conductivity, is widely used as an interconnector or substrate within microelectronic packages. If a small amount of oxygen is introduced to the surface of the copper, a eutectic liquid forms above 1065 °C. The eutectic liquid wets many ceramics well; it is thus possible to bond slightly oxidized copper to many ceramics directly. The present report summarizes previous results on three systems, Al2O3/Cu, AlN/Cu, and Si3N4/Cu laminates, prepared by the eutectic bonding process. The reported data demonstrate that ceramic/copper interfaces prepared with this technique are strong. Though little attention has been paid to the thermal characteristics of ceramic/copper laminates, the limited data suggest that the thermal conductivity of the laminates is high, the potential for using the laminates for thermal dissipation is thus high. In the present report, the current status for the technique is summarized; critical topics for further improvement are also proposed.