Selective etch for metal-containing materials

A method of etching aluminum oxide, the method comprising:

• flowing a gas-phase oxygen-hydrogen-containing precursor into the substrate processing region, wherein the gas-phase oxygen-and-hydrogen-containing precursor comprises an OH group;
• flowing a halogen-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a remote plasma in the remote plasma region to produce plasma effluents, wherein the halogen-containing precursor comprises one or more precursors selected from the group consisting of atomic chlorine, atomic bromine, molecular bromine (Br2), molecular chlorine (Cl2), hydrogen chloride (HCl), hydrogen bromide (HBr), boron tribromide (BBr3), and boron trichloride (BCl3);
• and
• etching the aluminum oxide from a substrate by flowing the plasma effluents into the substrate processing region through through-holes in a showerhead, wherein the showerhead is disposed between the remote plasma region and the substrate processing chamber.