Semiconductor wafer processing apparatus and method

A wafer stage for holding a semiconductor wafer in a plasma treatment apparatus by setting the wafer on the wafer stage, said wafer stage comprising:

• a base material equipped with refrigerant flow paths for allowing a refrigerant for temperature adjustment to flow,
• a stress-reducing member provided on the wafer setting side of said base material and having a smaller thermal expansion coefficient than does said base material,
• a dielectric film provided on the wafer setting side of said stress-reducing member, and
• a deflection-preventing member provided on the wafer non-setting side of said base material and having a smaller thermal expansion coefficient than does said base material, wherein said stress-reducing member has a cylindrical and internally convex level difference portion with a diameter smaller than the outside diameter of a semiconductor wafer to be set thereon, and a ring member made of carbon, Si or SiC is mounted on said dielectric film around the periphery of said level difference portion.

A wafer stage comprising:

• a base material equipped with refrigerant flow paths for allowing a refrigerant for temperature adjustment to flow,
• a stress-reducing member brazed to the wafer setting side of said base material and having a smaller thermal expansion coefficient than does said base material,
• a dielectric film provided on the wafer setting side of said stress-relaxing member, and
• a deflection-preventing member brazed to the wafer non-setting side of said base material and having a smaller thermal expansion coefficient than does said base material.