US 12,144,067 B2
Ceramic heater
Masaki Ishikawa, Handa (JP); and Shuichiro Motoyama, Nagoya (JP)
Assigned to NGK INSULATORS, LTD., Nagoya (JP)
Filed by NGK INSULATORS, LTD., Nagoya (JP)
Filed on Apr. 21, 2021, as Appl. No. 17/301,992.
Application 17/301,992 is a continuation of application No. PCT/JP2019/050428, filed on Dec. 23, 2019.
Claims priority of application No. 2019-011302 (JP), filed on Jan. 25, 2019.
Prior Publication US 2021/0243850 A1, Aug. 5, 2021
Int. Cl. H05B 3/26 (2006.01); H01L 21/67 (2006.01)
CPC H05B 3/265 (2013.01) [H01L 21/67103 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A ceramic heater comprising:
a ceramic plate that has a wafer placement surface;
a tubular shaft that is joined with the ceramic plate to a surface of the ceramic plate opposite the wafer placement surface;
a main resistance heating element that is disposed on a first plane parallel with the wafer placement surface in the ceramic plate and that has a coil shape; and
a sub resistance heating element that is disposed on a second plane parallel with the first plane in the ceramic plate, that complements heating with the main resistance heating element, and that has a two-dimensional shape;
wherein the main resistance heating element is disposed in m zones on the first plane respectively, wherein m is an integer of 1 or more, and wherein each of the m main resistance heating element zones has a pair of main terminals for a total of 2m main terminals;
wherein the sub resistance heating element is disposed in n zones on the second plane respectively, wherein n is an integer larger than m, and wherein each of the n sub resistance heating element zones has a pair of sub terminals for a total of 2n sub terminals;
wherein the sub resistance heating element having the two-dimensional shape is nearer than the main resistance heating element having the coil shape to a hole and a pair of portions of the sub resistance heating element that is positioned around the hole are located between a pair of portions of the main resistance heating element that is positioned around the hole in plan view;
wherein the sub resistance heating element overlaps a terminal of the main resistance heating element in a plan view of the wafer placement surface; and
wherein the 2m terminals of the main resistance heating element zones and the 2n terminals of the sub resistance heating element zones are all disposed in the tubular shaft in a plan view of the wafer placement surface.