Patent ID: 8540819

Claim:
A ceramic heater for a semiconductor substrate process comprising: a mounting plate on which the substrate is mounted; and a supporter configured to support the mounting plate, wherein the mounting plate includes: a first base made of a ceramic sintered body and having a mounting surface on which the substrate is mounted, and having a lower surface provided on an opposite side to the mounting surface; and a second base made of a ceramic sintered body and having an upper surface bonded to the lower surface of the first base, and having a lower surface provided on an opposite side to the upper surface, the supporter is made of a ceramic sintered body, is bonded to the lower surface of the second base, and includes a first penetration hole penetrating from one end of the supporter to the other end of the supporter, a first region, a first groove and a second region are defined on the mounting surface of the first base, the first region has a first surface contacting with the mounted substrate; the first groove is provided in a portion covered with the substrate and surrounds the first region; and the second region has a second surface directly adjacent to and surrounding the first groove, the first base has: an adsorber configured to adsorb the mounted substrate onto the first surface; and a plurality of holes each penetrating from a bottom surface of the first groove to the lower surface of the first base, at least one of the upper surface of the second base and the lower surface of the first base is provided with a second groove connected to each of the plurality of holes, the second base has a second penetration hole connected to the second groove and to the first penetration hole, the first groove is supplied with an inert gas through the first penetration hole, the second penetration hole, the second groove, and the plurality of holes, the entirety of the second surface of the second region is located lower than the first surface of the first region and higher than a bottom surface of the first groove, and wherein a portion of the second surface of the second region is covered with the mounted substrate, wherein an annular convex portion surrounds the second surface of the second region, and wherein an inside wall of the convex portion has a tapered surface that surrounds a space formed between the mounted substrate and the second surface of the second region so as to openly enlarge outward from the bottom upward.