Wafer placement table

A wafer placement table in which a cooling plate having a refrigerant flow channel is provided on a bottom surface side of a ceramic plate having a wafer placement surface on a top surface of the ceramic plate and incorporating an electrode, the wafer placement table comprising

• a horizontal space provided parallel to the wafer placement surface at a location closer to the wafer placement surface than the refrigerant flow channel in the wafer placement table and having an overlapping part that overlaps the refrigerant flow channel along the refrigerant flow channel in plan view,
• the cooling plate is an electrically conductive plate or includes at least an electrically conductive plate in an upper layer,
• the electrically conductive plate is bonded to a bottom surface of the ceramic plate via an electrically conductive bonding layer,
• wherein the horizontal space comprises three or more annular shaped gas intermediate passages at a bonding interface of the electrically conductive bonding layer and the cooling plate,
• the wafer placement table has a plurality of gas supply passages extending from the three or more annular shaped gas intermediate passages to the wafer placement surface for supplying back-side gas to the wafer placement surface,
• wherein the overlapping part of the three or more annular shaped gas intermediate passages that overlap the refrigerant flow channel is greater than or equal to 75% of a total length of a center line of the three or more annular shaped gas intermediate passages when viewed in plan.