A wafer processing apparatus is fabricated by depositing a film electrode onto the surface of a base substrate, the structure is then overcoated with a protective coating film layer comprising at least one of a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and combinations thereof. The film electrode has a coefficient of thermal expansion (CTE) that closely matches the CTE of the underlying base substrate layer as well as the CTE of the protective coating layer.