Abstract: A metal layer is bonded to a ceramic substrate in a method, wherein a first metal layer (e.g., a copper film) is first applied to a surface of the ceramic substrate. The ceramic substrate, with the first metal layer applied thereto, is then heated in an atmosphere including oxygen (e.g., to a temperature below the eutectic temperature of the metal oxide) to form an adhesion-promotion layer. A second metal layer (e.g., a copper foil) is then bonded to the adhesion-promotion layer. Where the metal is copper, the adhesion promotion layer can include copper oxide and copper aluminum oxide.