Abstract: An improved eutectic oxide bonding method is applied for bonding a metallic copper foil to a nonmetallic substrate by forming a liquid phase derived from a eutectic oxide composition. A metallic copper thin film is initially deposited onto the substrate and heated in a low oxygen atmosphere under suitable conditions to form a cuprous oxide film. A metallic copper foil is positioned on the substrate in contact with the cuprous oxide film. Preferably, the assembly is initially heated at a temperature below the eutectic melting point to soften the foil and promote intimate contact between the foil and the cuprous oxide film. Thereafter, the assembly is heated above the eutectic melting point to form a liquid phase at the interface of the foil and the cuprous oxide film, and maintained at the temperature for a time sufficient to dissolve the oxide film, whereupon the liquid phase wets the substrate. The assembly is cooled, and the liquid phase is solidified to bond the foil to the substrate.