Electrostatic chuck

Patent metadata

Field	Value
Publication number	US-9960067-B2
Application number	US-201414777879-A
Country	US
Kind code	B2
Filing date	Mar 27, 2014
Priority date	Mar 29, 2013
Publication date	May 1, 2018
Grant date	May 1, 2018

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.

First claim

The invention claimed is:

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 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 insulator plug is not exposed to an ambient environment outside of the ceramic dielectric substrate.

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 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.

5. 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.

6. 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.

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

8. 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 −6 /° C. or more and 10.0×10 −6 /° C. or less.

9. 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.

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 a 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.

19. 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.

20. 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.

21. The electrostatic chuck according to claim 20 , wherein the ceramic insulator film engages with the face.

Assignees

• Toto Ltd

Inventors

• Anada Kazuki
• Yoshii Yuichi

Classifications

• H10P72/0434 Primary

  mainly by convection · CPC title

• H10P72/72

  using electrostatic chucks · CPC title

• H10P72/722 Primary

  Details of electrostatic chucks · CPC title

• Y10T279/23

  with magnetic or electrostatic means · CPC title

• H01L21/67109

  Electricity · mapped topic