Ceramic heater
A ceramic heater includes: a ceramic plate having a wafer placement surface on a surface thereof; zone heaters embedded in the ceramic plate so as to correspond to zones defined by dividing the surface of the ceramic plate into multiple sections; terminals connected to ends of the zone heaters via internal wires of the ceramic plate; terminal collection regions in which the plurality of terminals are collectively arranged; and non-terminal regions in which no terminal is arranged. The ceramic heater includes, as the zone heaters, a terminal-collection-region zone heater provided in a zone corresponding to the terminal collection regions, and a non-terminal regions zone heater provided in a zone corresponding to the non-terminal regions.
1 . A ceramic heater comprising:
a ceramic plate having a wafer placement surface on a surface thereof;
zone heaters embedded in the ceramic plate so as to correspond to zones defined by dividing the surface of the ceramic plate into multiple sections;
terminals connected to ends of the zone heaters via internal wires of the ceramic plate;
a terminal collection region that is provided in the ceramic plate and in which the plurality of terminals are collectively arranged; and
a non-terminal region that is provided in the ceramic plate and in which no terminal is arranged,
wherein the zone heaters include a terminal-collection-region zone heater provided in a zone corresponding to the terminal collection region, and a non-terminal-region zone heater provided in a zone corresponding to the non-terminal region;
wherein the ceramic plate is circular in a plan view;
wherein the plurality of zones include a circular region zone concentric with the ceramic plate, and annular divided zones formed by dividing an annular band around the circular region zone into a plurality of sections along a radial direction of the ceramic plate;
wherein the zone corresponding to the terminal collection region is selected from the plurality of annular divided zones; and
wherein the plurality of terminals arranged in the terminal collection region are provided over an arc of the annular divided zone corresponding to the terminal collection region from one end to the other end of the zone.
2 . The ceramic heater according to claim 1 , wherein the plurality of terminals provided in the terminal collection region are arranged in an arc along a circle concentric with the ceramic plate or linearly in a tangential direction of a circle concentric with the ceramic plate.
3 . The ceramic heater according to claim 1 , wherein the terminal collection region is provided so as to be located on the outermost circumference of the ceramic plate.
4 . The ceramic heater according to claim 1 , further including a cooling plate joined to a lower surface of the ceramic plate.