Patent ID: 7633738

Claim:
An electrostatic chuck, comprising: a base made of substantially disc-like alumina ceramics and having a substrate mounting surface; an electrode embedded in the base in parallel to the substrate mounting surface of the base; and a terminal loaded into a terminal hole drilled toward the electrode from the opposite side surface of the substrate mounting surface of the base, wherein the electrode has approximately constant thickness and includes, at a portion thereof facing the terminal hole, a protruded portion with a substantially conical trapezoidal shape, the protruded portion being made of the same type of material as the electrode and having a first surface bonded to an end surface of the terminal, wherein the diameter of the end surface of the terminal that is bonded to the first surface of the protruded portion is larger than the diameter of the first surface of the protruded portion, and wherein in the protruded portion, an angle made by a flat surface on the terminal side of the electrode, from which the protruded portion is protruded, and an inclined surface of the protruded portion is 40° or less, and a distance from the flat surface on the terminal side of the electrode to the first surface of the protruded portion is 0.01 mm to less than 0.8 mm.