Ceramic heater
AssigneeNGK Insulators, Ltd.
InventorsTomohiro TAKAHASHI, Ryohei MATSUSHITA
Life of this patent
Estimating the term…
Abstract
A ceramic heater includes a ceramic plate in which inner circumferential side and outer circumferential side resistance heating elements are built in; and a cylindrical shaft joined to a rear surface of the ceramic plate. The long hole extends from a start point of the ceramic plate to a terminal position of the outer circumferential portion of the ceramic plate. The entrance portion of the long hole is a long groove. The long groove is provided to extend from the start point to an extended area. Terminals are provided at positions other than the long groove and in a shaft inside area.
Claims18
A ceramic heater comprising:
- a disc-shaped ceramic plate having a wafer mounting surface;
- a cylindrical shaft having a small diameter portion and a large diameter portion having an end face joined to a rear surface of the ceramic plate, the rear surface being on an opposite side of the wafer mounting surface;
- an inner circumferential side resistance heating element which is embedded in an inner circumferential portion of the ceramic plate;
- an outer circumferential side resistance heating element which is embedded in an outer circumferential portion of the ceramic plate;
- attached components including a pair of terminals of the inner circumferential side resistance heating element and a pair of terminals of the outer circumferential side resistance heating element;
- and
- a long hole extending from a start point in an inside area of the small diameter portion of the rear surface of the ceramic plate to a predetermined terminal position of the outer circumferential portion of the ceramic plate;
- wherein an internal space of the cylindrical shaft has a circular cylinder shaped space having a diameter equal to an inner diameter of the small diameter portion, and a ring-shaped extended space which is on an outer side of the circular cylinder shaped space and surrounded by the large diameter portion,
- an entrance portion of the long hole is a long groove,
- the long groove is provided to extend from the start point to an extended area within the extended space of the rear surface of the ceramic plate, and
- the attached components are provided at a position other than the long groove and within the inside area of the small diameter portion of the rear surface of the ceramic plate.
Dependencies are inferred from the claim text.