Abstract: A substrate processing apparatus includes: a process chamber; a substrate support structure disposed at a lower portion of the process chamber and configured to accommodate a substrate; and a gas supply module disposed at an upper portion of the process chamber and supplying a process gas to the substrate, wherein the gas supply module includes a showerhead that includes: a first showerhead body including a plurality of injection ports configured to transfer gas transferred from a gas inlet into the process chamber; and a coating layer covering the first showerhead body and including aluminum fluoride, wherein the first showerhead body includes a metal matrix composite (MMC).