Patent ID: 11963269
Assignee: NGK INSULATORS, LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A ceramic heater comprising:
a ceramic plate having a surface that serves as a wafer placement surface;
a resistance heating element that is embedded in the ceramic plate;
a tubular shaft that supports the ceramic plate from a rear surface of the ceramic plate;
a singular cylindrical shaped recess that is formed in a within-shaft region of the rear surface of the ceramic plate and having a constant diameter equal to a size an inside diameter of the tubular shaft, the within-shaft region being surrounded by the tubular shaft;
terminals that are disposed to be exposed at a side surface of the recess and that supply electric power to the resistance heating element; and
wherein the resistance heating element includes an inner-peripheral-side resistance heating element disposed in an inner-peripheral-side zone of the wafer placement surface and an outer-peripheral-side resistance heating element disposed in an outer-peripheral-side zone of the wafer placement surface, the terminals of the outer-peripheral-side resistance heating element are embedded in the ceramic plate at positions near the side surface of the recess and are disposed to be exposed at the side surface of the recess, and the terminals of the inner-peripheral-side resistance heating element are embedded in the ceramic plate at positions near the bottom surface of the recess and are disposed to be exposed at the within-shaft region of the rear surface of the ceramic plate.