Electrostatic chuck

• US 20060221539A1
• Filed: 03/30/2006
• Published: 10/05/2006
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Niterra Co., Ltd.
• Original Assignee: NGK Spark PLUG Company Limited (Niterra Co., Ltd.)
• Inventors: Kameyama, Ryosuke, Morita, Naotoshi
• Granted Patent: US 8,525,418 B2
• Time in Patent Office: Days
• US Class Current: 361/234
• CPC Class Codes: H01L 21/67103 mainly by conduction
• CPC Class Codes: H01L 21/6831 using electrostatic chucks

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.

Claims

1. 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.

2. The electrostatic chuck as claimed in claim 1, wherein

said heating element is formed from substantially the same material, and has substantially the same thickness and substantially the same width in both said projection region and said outer region, and a per unit area of said heating element in said projection region is 50% or less of a per unit area of said heating element in said outer region.

4. The electrostatic chuck as claimed in claim 1, wherein said heating element linearly extends in a lateral direction, said heating element in the vicinity of said projection region has a substantially U-like shape, and a convex side of the U-like shape faces said projection region.

6. The electrostatic chuck as claimed in claim 1, wherein said heating element is spaced apart from said projection region by 1 mm or more.

8. The electrostatic chuck as claimed in claim 1, wherein said ceramic body is integrated with said metal base.

10. The electrostatic chuck as claimed in claim 1, wherein said ceramic body comprises alumina.

3. 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.

5. The electrostatic chuck as claimed in claim 3, wherein said heating element linearly extends in a lateral direction, said heating element in the vicinity of said projection region has a substantially U-like shape, and a convex side of the U-like shape faces said projection region.

7. The electrostatic chuck as claimed in claim 3, wherein said heating element is spaced apart from said projection region by 1 mm or more.

9. The electrostatic chuck as claimed in claim 3, wherein said ceramic body is integrated with said metal base.

11. The electrostatic chuck as claimed in claim 3, wherein said ceramic body comprises alumina.