Wafer placement table

A wafer placement table comprising:

• a central ceramic base that has an upper surface including a wafer placement surface and that contains an electrode;
• an outer circumferential ceramic base that has an upper surface including a focus ring placement surface, that is disposed on an outer circumference of the central ceramic base, that is separated from the central ceramic base, and that has an annular shape;
• and
• a cooling base that includes a central portion that is joined to a lower surface of the central ceramic base, an outer circumferential portion that is joined to a lower surface of the outer circumferential ceramic base, and a coupler that couples the central portion and the outer circumferential portion with each other,
• wherein the cooling base has a central refrigerant flow path that is formed in the central portion and an outer circumferential refrigerant flow path that is formed in the outer circumferential portion, and
• wherein the coupler is formed outside an outermost edge of the central refrigerant flow path and inside an innermost edge of the outer circumferential refrigerant flow path, and has one or more upward grooves that open from an upper surface, and that have an annular shape, and has one or more downward grooves that open from a lower surface, that have a ceiling surface higher than a bottom surface of the one or more upward grooves, and that have an annular shape.