Electrostatic chuck
AssigneeNgk Spark Plug Co., Ltd.
InventorsNaotoshi Morita, Ryosuke Kameyama
Life of this patent
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Abstract
An electrostatic chuck including a metal base having a through hole; a ceramic body covering the through hole; a suction electrode provided in the ceramic body; and a heating element provided in the ceramic body. A projection region defined by projecting the through hole toward the ceramic body is differentiated from an outer region which is determined by magnifying the projection region at a similarity ratio of three while setting an areal center of gravity of the projection region as a center of similarity, but excluding an interior of the projection region. Furthermore, the heating element is arranged such that a heating value per unit area in the projection region is 50% or less of a heating value per unit area in the outer region.
Claims11
An electrostatic chuck comprising:
- a metal base having a through hole;
- a ceramic body covering said through hole;
- a suction electrode provided in said ceramic body;
- and
- a heating element provided in said ceramic body,
- wherein
- a heating value per unit area in a projection region is 50% or less of a heating value per unit area in an outer region, wherein said projection region is a region defined by projecting said through hole toward said ceramic body, and said outer region is a region determined by magnifying said projection region at a similarity ratio of three while setting an areal center of gravity of said projection region as a center of similarity, but excluding an interior of said projection region.
An electrostatic chuck comprising:
- a metal base having a through hole;
- a ceramic body covering said through hole;
- a suction electrode provided in said ceramic body;
- and
- a heating element provided in said ceramic body,
- wherein said heating element is not present in a projection region defined by projecting said through hole toward said ceramic body.
Dependencies are inferred from the claim text.