Patent ID: 11874180
Assignee: NGK INSULATORS, LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 6:
7. 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; and
a thermocouple passage that extends from a start point in a within-shaft region of the rear surface of the ceramic plate, the within-shaft region being surrounded by the tubular shaft, toward an outer peripheral portion of the ceramic plate,
wherein the thermocouple passage includes a branch point at a midway position, a first branch passage extending from the branch point to a first terminal end position, and a second branch passage extending from the branch point to a second terminal end position that is different from the first terminal end position.