Provided are methods of patterning metal gate structures including a high-k gate dielectric. In an embodiment, a soluble hard mask layer may be used to provide a masking element to pattern a metal gate. The soluble hard mask layer may be removed from the substrate by water or a photoresist developer. In an embodiment, a hard mask including a high-k dielectric is formed. In a further embodiment, a protection layer is formed underlying a photoresist pattern. The protection layer may protect one or more layers formed on the substrate from a photoresist stripping process.