ELECTROSTATIC CHUCK

• US 20160276198A1
• Filed: 03/27/2014
• Published: 09/22/2016
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Toto Limited
• Original Assignee: Toto Limited
• Inventors: YOSHII, Yuichi, ANADA, Kazuki
• Granted Patent: US 9,960,067 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 21/6833 Details of electrostatic chucks
• CPC Class Codes: Y10T 279/23 with magnetic or electrostatic means

Abstract

According to an aspect of an embodiment of the invention, there is provided an electrostatic chuck including: 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 provided 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; and an insulator plug including a ceramic porous body provided in the gas feed channel and a ceramic insulating film provided between the ceramic porous body and the gas feed channel 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.

Claims

1. 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 provided 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; and

an insulator plug including a ceramic porous body provided in the gas feed channel and a ceramic insulating film provided between the ceramic porous body and the gas feed channel 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.

2. The chuck according to claim 1, wherein thermal expansion coefficient of the ceramic insulating film is equal to each of thermal expansion coefficient of the ceramic porous body and thermal expansion coefficient of the ceramic dielectric substrate.

3. The chuck according to claim 1, wherein arithmetic average roughness of a surface of the ceramic insulating film is smaller than arithmetic average roughness of the surface of the ceramic porous body and larger than arithmetic average roughness of a surface of the ceramic dielectric substrate.

4. The chuck according to claim 1, wherein

porosity of the ceramic insulating film is 10 percent or less, and

porosity of the ceramic porous body is 30 percent or more and 60 percent or less.

5. The chuck according to claim 1, wherein

density of the ceramic insulating film is 3.0 grams per cubic centimeter or more and 4.0 grams per cubic centimeter or less, and

density of the ceramic porous body is 1.5 grams per cubic centimeter or more and 3.0 grams per cubic centimeter or less.

6. The chuck according to claim 1, wherein ratio of difference between thermal expansion coefficient of the ceramic porous body and thermal expansion coefficient of the ceramic insulating film with reference to the thermal expansion coefficient of the ceramic porous body is 100% or less.

7. The chuck according to claim 1, wherein thermal expansion coefficient of each of the ceramic porous body and the ceramic insulating film is 7.0×

10<sup>−

6</sup>/°

C. or more and 10.0×

10<sup>−

6</sup>/°

C. or less.

8. The chuck according to claim 1, wherein thermal conductivity of each of the ceramic porous body and the ceramic insulating film is 0.3 watts per meter kelvin or more and 10 watts per meter kelvin or less.

9. The chuck according to claim 3, wherein

the arithmetic average roughness of the surface of the ceramic insulating film is 0.5 micrometers or more and 4 micrometers or less, and

the arithmetic average roughness of the surface of the ceramic porous body is 5 micrometers or more and 20 micrometers or less.

10. The chuck according to claim 1, wherein the ceramic insulating film is a ceramic sprayed film provided on a side surface of the ceramic porous body.

11. The chuck according to claim 1, wherein ratio of length to outer diameter of the ceramic porous body is 0.6 or more.

12. The chuck according to claim 11, wherein the outer diameter of the ceramic porous body is 1 millimeter or more.

13. The chuck according to claim 11, wherein the length of the ceramic porous body is 3 millimeter or more.

14. The chuck according to claim 1, wherein L/D is 5 or more, where D is inner diameter of the through hole, and L is distance from center of the through hole to outer periphery of the ceramic porous body.

15. The chuck according to claim 1, wherein flow rate of He gas flowing out per the through hole is 0.5 sccm or more and 14 sccm or less when pressure difference of the He gas is 30 Torr.

16. The chuck according to claim 1, wherein flow rate of He gas flowing out per the ceramic porous body is 3 sccm or more and 24 sccm or less when pressure difference of the He gas is 30 Torr.

17. The chuck according to claim 1, wherein inner diameter of the through hole is 0.05 millimeters or more and 1 millimeter or less.

18. The chuck according to claim 1, wherein outer diameter of the ceramic porous body is 7 millimeters or less.