Electrostatic chuck

An electrostatic chuck comprising:

• a ceramic dielectric substrate including a first major surface for mounting a clamped target, a second major surface on opposite side from the first major surface, and a through hole extending through the ceramic dielectric substrate from the second major surface to the first major surface;
• a metallic base plate supporting the ceramic dielectric substrate and including a gas feed channel communicating with the through hole, the base plate having a hollow socket formed therein in communication with the gas feed channel;
• and
• an insulator plug including a ceramic porous body provided in the gas feed channel, the insulator plug disposed in the socket of the base plate below, contacting and substantially covered by the ceramic dielectric substrate, and a ceramic insulating film provided between side portions of the ceramic porous body and the hollow socket of the base plate, the ceramic insulating film having a high insulation performance and being denser than the ceramic porous body, the ceramic insulating film biting into the ceramic porous body from a surface of the ceramic porous body,
• wherein the ceramic dielectric substrate includes an electrode for clamping the target, and the insulator plug is provided below and spaced away from the electrode.

An electrostatic chuck comprising:

• a ceramic dielectric substrate including a first major surface for mounting a clamped target, a second major surface on opposite side from the first major surface, and a through hole extending through the ceramic dielectric substrate from the second major surface to the first major surface;
• a metallic base plate supporting the ceramic dielectric substrate and including a gas feed channel communicating with the through hole, the base plate having a hollow socket formed therein in communication with the gas feed channel;
• and
• an insulator plug including a ceramic porous body provided in the gas feed channel, the insulator plug disposed in the socket of the base plate below, contacting and substantially covered by the ceramic dielectric substrate, and a ceramic insulating film provided between side portions of the ceramic porous body and the hollow socket of the base plate, the ceramic insulating film having a high insulation performance and being denser than the ceramic porous body, the ceramic insulating film biting into the ceramic porous body from a surface of the ceramic porous body,
• wherein the gas feed channel has a face along a direction perpendicular to the second main surface of the ceramic dielectric substrate, and the insulator plug is provided at the face.