Patent ID: 11956863
Assignee: NGK INSULATORS, LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  C | IPC C  H

Claim 5:
6. A multi-zone heater, comprising:
a disc-shaped ceramic substrate that has a wafer placement surface;
a coil-shaped or mesh-shaped central zone heater provided in a central portion of the ceramic substrate;
at least one coil-shaped or mesh-shaped outer circumferential zone heater that is provided so as to correspond to at least one outer circumferential zone in an outer circumferential portion of the ceramic substrate in a same plane as a plane in which the central zone heater is disposed and that is routed throughout the at least one outer circumferential zone in a unicursal manner from one end portion to the other end portion in the at least one outer circumferential zone;
a first elemental wire portion that extends from a first terminal disposed in the central portion of the ceramic substrate, that passes through the central portion, that is connected to the one end portion of the at least one outer circumferential zone heater, and that has a meandering shape in plan view and a plurality of curved portions; and
a second elemental wire portion that extends from a second terminal disposed in the central portion of the ceramic substrate, that passes through the central portion, that is connected to the other end portion of the at least one outer circumferential zone heater, and that has a meandering shape in plan view and a plurality of curved portions,
wherein the first elemental wire portion and the second elemental wire portion have respective parts where the first elemental wire portion and the second elemental wire portion are close to each other, and the first elemental wire portion and the second elemental wire portion have respective parts where the first elemental wire portion and the second elemental wire portion are spaced from each other,
a distance between the first elemental wire portion and the second elemental wire portion in the part where the first elemental wire portion and the second elemental wire portion are close to each other is smaller than a distance between the first elemental wire portion and the second elemental wire portion in the part where the first elemental wire portion and the second elemental wire portion are spaced from each other, and
a heat generation amount in the part where the first elemental wire portion and the second elemental wire portion are close to each other is greater than a heat generation amount in the part where the first elemental wire portion and the second elemental wire portion are spaced from each other.