Patent ID: 11874180
Assignee: NGK INSULATORS, LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H | IPC G  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; 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, to a terminal end position in an outer peripheral portion of the ceramic plate,
wherein the thermocouple passage includes a stepped portion provided at an intermediate position between the start point and the terminal end position, a long-distance portion extending from the start position to the terminal end position, and a short-distance portion extending from the start position to the intermediate position, and
wherein the long-distance portion is adapted for inserting and holding a thermocouple in contact with the terminal end position, and the short-distance portion is adapted for inserting and holding a thermocouple in contact with the stepped portion at the intermediate position.