Wafer placement table
A wafer placement table includes: a ceramic plate having a pore extending vertically through the ceramic plate, a conductive plate bonded to a lower surface of the ceramic plate and having a gas supply passage; a plug chamber that is in communication with the pore and the gas supply passage; an insulating gas passage plug located in the plug chamber and a dense insulating film. The dense insulating film allows ventilation at a gas outlet portion that is a portion of an upper surface of the insulating gas passage plug and serves as a gas flow path to the pore, and the dense insulating film is disposed across the upper surface of the conductive plate and the upper surface of the insulating gas passage plug to cover a boundary between the upper surface of the conductive plate and the upper surface of the insulating gas passage plug.
1. A wafer placement table comprising:
a ceramic plate having an upper surface serving as a wafer placement surface, a pore extending vertically through the ceramic plate, and a built-in electrode;
a conductive plate bonded to a lower surface of the ceramic plate and having a gas supply passage;
a plug chamber that is a recess extending from an upper surface of the conductive plate toward a lower surface of the conductive plate and is in communication with the pore and the gas supply passage;
an insulating gas passage plug located in the plug chamber and through which gas is allowed to pass; and
a dense insulating film allowing ventilation at a gas outlet portion that is a portion of an upper surface of the insulating gas passage plug and serves as a gas flow path to the pore, the dense insulating film being disposed across the upper surface of the conductive plate and the upper surface of the insulating gas passage plug to cover a boundary between the upper surface of the conductive plate and the upper surface of the insulating gas passage plug;
wherein the upper surface of the insulating gas passage plug has a protrusion having an upper surface serving as the gas outlet portion, and the upper surface of the dense insulating film and the upper surface of the protrusion are flush with each other.
2. The wafer placement table according to claim 1 ,
wherein the dense insulating film is a thermal sprayed film or an aerosol deposition film.
3. The wafer placement table according to claim 1 ,
further comprising an elastic member between a lower surface of the insulating gas passage plug and a bottom surface of the plug chamber.
4. The wafer placement table according to claim 3 ,
wherein the elastic member is a heat-resistant resin.
5. The wafer placement table according to claim 1 ,
wherein the insulating gas passage plug is a porous member.
6. The wafer placement table according to claim 2 ,
further comprising an elastic member between a lower surface of the insulating gas passage plug and a bottom surface of the plug chamber.
7. The wafer placement table according to claim 6 ,
wherein the elastic member is a heat-resistant resin.