IMPROVED ADHESION OF COPPER ON AL2O3

Improved methods for Al2O3 metallization by Cu are described. Good adhesion between Cu and Al2O3 substrate depends on the formation of chemical bonds between the substrate and the metallic layer. The temperature needed for the formation of a CuAl2O4 spinel interface is reduced from 1050-degrees-C to 900-degrees-C by the addition of various oxides. The adhesion between the CuAl2O4 interface and deposited Cu is stronger then the tensile strength of pure Cu. Plasma techniques for the formation of a Cu containing interface are also described. Bombardment of a Cu film with Xe+ ions in a rf-glow discharge implants Cu atoms into the substrate to a depth of 5 nm, as determined by SIMS depth profiling. Methods for reduction of the CuAl2O4 surface for subsequent metallization are also presented.