Interfacial structure, process control and adhesion strength of copper to aluminum oxide and aluminum nitride direct bonds

Gas-metal eutectic bonded Cu to The Cu-The Cu-O eutectic melt dissolved the minor constituents (MgO, CaO & SiOA processing study indicated that eutectic bonding by introducing oxygen in the gas environment was undesirable. This condition caused bulk Cu melting. It was preferable to preoxidize the Cu surface and then bond in an inert atmosphere. This gave a larger time/temperature operation window and more uniform bonds.For direct bonded Cu to AlN, preoxidation of the AlN surface was required for wetting by the Cu-O eutectic melt. Both bond strength and fracture mode was found to depend on the degree of preoxidation, the bonding environment and the AlN sample source.An optimum temperature existed for the AlN preoxidation, about 1300The The variation in bond strength among different AlN samples was attributed to differences in oxidation behavior. High adhesion strength was associated with a thicker...