# US 2021/0242053 A1 · Ceramic heater

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- Number: US 2021/0242053 A1
- Document ID: US20210242053A1
- Status: Published application
- Kind: A1
- Application number: 17/111,714
- Filed: 2020-12-04
- Published: 2021-08-05
- Earliest claimed: 2020-02-03
- Assignees: NGK Insulators, Ltd.
- Applicants: Ngk Insulators, Ltd.
- Inventors: Ryohei MATSUSHITA; Shuichiro MOTOYAMA
- Web page: https://patentgrep.com/patent/US20210242053A1

## CPC

- H10P 72/0602: {Temperature monitoring}
- H05B 1/0233: {for semiconductors manufacturing}
- H05B 3/265: {the insulating base being an inorganic material, e.g. ceramic (H05B3/262 takes precedence)}
- H05B 3/283: {the insulating material being an inorganic material, e.g. ceramic}
- H10P 72/0432: {mainly by conduction}
- H01J 37/32724: {Temperature}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A ceramic heater includes a ceramic plate having a front surface that serves as a wafer placement surface, resistance heating elements that are 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. The thermocouple passage includes a curved portion between the start point and the terminal end position.

## Claims

### Claim 1

A ceramic heater comprising:
a ceramic plate having a front 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 curved portion between the start point and the terminal end position.

### Claim 2 (depends on 1)

The ceramic heater according to claim 1,
wherein the curved portion is disposed while avoiding a predetermined location defined in the ceramic plate.

### Claim 3 (depends on 1)

The ceramic heater according to claim 1,
wherein the curved portion is curved in a planar direction of the ceramic plate.

### Claim 4 (depends on 1)

The ceramic heater according to claim 1,
wherein the curved portion is curved in a thickness direction of the ceramic plate.

### Claim 5 (depends on 4)

The ceramic heater according to claim 4,
wherein the terminal end position is disposed between a plane in the ceramic plate where the resistance heating element is embedded and the wafer placement surface.

### Claim 6 (depends on 1)

The ceramic heater according to claim 1,
wherein the curved portion has a curvature radius of 20 mm or more.

### Claim 7 (depends on 1)

The ceramic heater according to claim 1, further comprising a thermocouple that is inserted into the thermocouple passage, wherein a temperature measurement portion at a tip end of the thermocouple reaches the terminal end position.