The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 07, 2023
Filed:
Nov. 25, 2019
Ngk Insulators, Ltd., Nagoya, JP;
Yutaka Unno, Handa, JP;
Shuichiro Motoyama, Nagoya, JP;
NGK Insulators, LTD., Nagoya, JP;
Abstract
A ceramic heater includes a ceramic substrate including, on an upper surface, a wafer mount surface that receives a wafer, and a heater electrode embedded in an inside of the ceramic substrate. The ceramic substrate includes a core portion and a surface layer portion disposed on a surface of the core portion. The surface layer portion has volume resistivity higher than volume resistivity of the core portion. The core portion has thermal conductivity higher than thermal conductivity of the surface layer portion. The surface layer portion is disposed over an area of at least one of a side surface of the core portion and an upper surface of the core portion, the area being not covered with the wafer.