Removable showerhead faceplate for semiconductor processing tools

An apparatus comprising:

• a showerhead faceplate, wherein:
• the showerhead faceplate is configured to removably mate with a showerhead backplate,
• the showerhead faceplate has a plate region having a plurality of gas distribution ports located therein,
• each gas distribution port extends through the showerhead faceplate,
• the showerhead faceplate includes one or more first planar thermal contact surfaces, each first planar thermal contact surface configured to contact a corresponding second planar thermal contact surface on the showerhead backplate when the showerhead faceplate is mated to the showerhead backplate,
• the one or more first planar thermal contact surfaces include an annular planar thermal contact surface that has an outer diameter of between 12″ and 18″ and that encircles the plate region when viewed along a first axis that is perpendicular to the annular planar thermal contact surface, and
• the annular planar thermal contact surface has a flatness less than or equal to a value between 800 μin and 1200 μin and a surface roughness Ra less than or equal to a value between 24 μin to 40 μin.