Ceramic heater and method of manufacturing the ceramic heater
An electrostatic chuck heater includes a resistance heating element. A region of the resistance heating element from one end to another end of the resistance heating element is divided into a plurality of sections. Recessed grooves are provided in the respective sections along a longitudinal direction of the resistance heating element in a surface. In a connection portion between the recessed grooves that are provided in the adjacent sections, a projection portion that extends along the connection portion is provided.
1 . A ceramic heater comprising:
a resistance heating element, wherein
a region of the resistance heating element from one end to another end of the resistance heating element is divided into a plurality of sections, wherein,
recessed grooves are provided in the respective sections along a longitudinal direction of the resistance heating element in a surface of the resistance heating element, and wherein,
in a connection portion between the recessed grooves that are provided in the adjacent sections, a projection portion that extends along the connection portion is provided, and
wherein a width of the recessed grooves for the respective sections is varied to vary the resistance of the resistance heating element between the plurality of sections.
2 . The ceramic heater according to claim 1 , wherein,
when a cross-section of the projection portion cut along a surface along the longitudinal direction of the resistance heating element is seen, the projection portion appears as a chevron shape having a foot width of smaller than or equal to 95 μm.
3 . The ceramic heater according to claim 1 , wherein
a depth of the recessed grooves is set to be a uniform value irrespective of the sections, and wherein
a width of the recessed grooves is set on a section-by-section basis.
4 . The ceramic heater according to claim 1 , wherein
a center line of the recessed grooves is coincident with a center line of the resistance heating element.
5 . The ceramic heater according to claim 1 , wherein
the recessed grooves are not provided in a portion of the resistance heating element in which a heat removal action is low.
6 . The ceramic heater according to claim 1 , wherein
regardless of whether a longitudinal direction of a shape of the sections in plan view is straight or curved, a longitudinal direction of a shape of the recessed grooves in plan view is straight.
7 . The ceramic heater according to claim 1 , wherein
regardless of whether a longitudinal direction of a shape of the sections in plan view is straight or curved, a foot width of the projection portion is uniform except for both end portions of the connection portion in a width direction of the recessed grooves.
8 . A method of manufacturing a ceramic heater, the method comprising the steps of:
(a) forming, on a surface of a first ceramic fired layer or an unfired layer, a resistance heating element or a precursor of the resistance heating element in a predetermined pattern;
(b) forming respective recessed grooves along the longitudinal direction of the resistance heating element or the precursor of the resistance heating element by radiating laser light to a plurality of sections obtained by dividing the resistance heating element or the precursor of the resistance heating element along a longitudinal direction of the resistance heating element or the precursor of the resistance heating element;
(c) obtaining a layered body by disposing, on the surface of the first ceramic fired layer or the unfired layer, a second ceramic unfired layer such that the second ceramic unfired layer covers the resistance heating element or the precursor of the resistance heating element; and
(d) obtaining the ceramic heater that includes the resistance heating element disposed in a ceramic substrate by performing hot press firing on the layered body, wherein,
in the step (b), in a connection portion between the recessed grooves that are provided in the adjacent sections, a projection portion that extends along the connection portion remains.