Methods and apparatus for high voltage electrostatic chuck protection

Patent metadata

Field	Value
Publication number	US-11289357-B2
Application number	US-201916550521-A
Country	US
Kind code	B2
Filing date	Aug 26, 2019
Priority date	Jun 27, 2019
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

Methods and apparatus for increasing voltage breakdown levels of an electrostatic chuck in a process chamber. A soft anodization layer with a thickness of greater than zero and less than approximately 10 microns is formed on an aluminum base of the electrostatic chuck. The soft anodization layer remains thermally elastic in a temperature range of approximately −50 degrees Celsius to approximately 100 degrees Celsius. An alumina spray coating is then applied on the soft anodization layer. The soft anodization layer provides thermal stress relief between the aluminum base and the alumina spray coating to reduce/eliminate cracking caused by the thermal expansion rate differences between the aluminum base and the alumina spray coating.

First claim

The invention claimed is:

1. An electrostatic chuck for holding substrates in a process chamber, the electrostatic chuck comprising:
an aluminum base;
an anodized layer on the aluminum base, wherein the anodized layer has a non-columnar structure and a thickness of greater than zero and less than approximately 10 microns; and
an alumina layer on the anodized layer, wherein the alumina layer has a thickness of approximately 200 microns to approximately 300 microns.

2. The electrostatic chuck of claim 1 , wherein the electrostatic chuck has a breakdown voltage of approximately 2 kV or more.

3. The electrostatic chuck of claim 1 , wherein the anodized layer is a soft anodized layer.

4. The electrostatic chuck of claim 1 , wherein the anodized layer is configured to provide thermal expansion and contraction stress relief between the aluminum base and the alumina layer to reduce cracking of the alumina layer.

5. The electrostatic chuck of claim 1 , wherein the alumina layer is formed by spray coating alumina on the anodized layer.

6. The electrostatic chuck of claim 1 , wherein the anodized layer provides approximately 10 volts of insulative protection for approximately every one micron of thickness.

7. The electrostatic chuck of claim 1 , wherein the anodized layer is thermally elastic in a temperature range of approximately −50 degrees Celsius to approximately 100 degrees Celsius.

8. An electrostatic chuck for holding substrates in a process chamber, the electrostatic chuck comprising:
an aluminum base;
an anodized layer on the aluminum base, wherein the anodized layer is a soft anodized layer with a non-columnar structure and a thickness of greater than zero and less than approximately 10 microns; and
an alumina layer on the anodized layer, wherein the alumina layer has a thickness of approximately 200 microns to approximately 300 microns, and

wherein the electrostatic chuck has a breakdown voltage of approximately 2 kV or more.

9. The electrostatic chuck of claim 8 , wherein the anodized layer is configured to provide thermal expansion and contraction stress relief between the aluminum base and the alumina layer to reduce cracking of the alumina layer.

10. The electrostatic chuck of claim 8 , wherein the alumina layer is formed by spray coating alumina on the anodized layer.

11. The electrostatic chuck of claim 8 , wherein the anodized layer provides approximately 10 volts of insulative protection for approximately every one micron of thickness.

12. The electrostatic chuck of claim 8 , wherein the anodized layer is thermally elastic in a temperature range of approximately −50 degrees Celsius to approximately 100 degrees Celsius.

13. The electrostatic chuck of claim 8 , wherein the breakdown voltage is approximately 2 kV to approximately 3 kV.

14. A method for increasing voltage breakdown levels of an electrostatic chuck, comprising:
forming a first layer on an aluminum base of the electrostatic chuck, the first layer being a first dielectric material with a non-columnar structure and thermally elastic properties in a temperature range of approximately −50 degrees Celsius to approximately 100 degrees Celsius; and
forming a second layer on the first layer, the second layer being a second dielectric material,
wherein the thermally elastic properties inhibit cracking of the second layer which has a coefficient of thermal expansion different from the aluminum base.

15. The method of claim 14 , further comprising:
forming the first layer on the aluminum base using a soft anodization process that does not produce a columnar structure in the first layer.

16. The method of claim 14 , further comprising:
forming the second layer by spray coating alumina on the first layer.

17. The method of claim 14 , further comprising:
forming the first layer on the aluminum base with a thickness of greater than zero and less than approximately 10 microns.

18. The method of claim 14 , further comprising:
forming the second layer on the first layer with a thickness of approximately 200 microns to approximately 300 microns.

19. The method of claim 14 , wherein the first dielectric material provides approximately 10 volts of insulative protection for approximately every one micron of thickness.

20. The method of claim 14 , wherein the first layer provides thermal expansion and contraction stress relief between the aluminum base and the second layer.

Assignees

• Applied Materials Inc

Inventors

• Wada Yuichi
• Ow Yueh Sheng
• Jupudi Ananthkrishna
• Goh Clinton
• Liew Kai Liang
• Babu Sarath

Classifications

• H10P72/722 Primary

  Details of electrostatic chucks · CPC title

• H10P72/7616

  characterised by a coating, a hardness or a material · CPC title

• H01L21/6833 Primary

  Electricity · mapped topic