Method for cleaning elements in vacuum chamber and apparatus for processing substrates

• US 8,337,629 B2
• Filed: 06/13/2012
• Issued: 12/25/2012
• Est. Priority Date: 08/25/2003
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Moriya, Tsuyoshi, Nagaike, Hiroshi, Nakayama, Hiroyuki
• Primary Examiner(s): Kornakov, Michael
• Assistant Examiner(s): BLAN, NICOLE R
• Application Number:
  US13/495,404
• Publication Number:
  US 20120247502A1
• Time in Patent Office: 195 Days
• Field of Search: None
• US Class Current: 134/21
• CPC Class Codes: B08B 3/12 by sonic or ultrasonic vibrations washing or rinsing machines for crockery or tableware using sonic or ultrasonic waves A47L15/13; of natural teeth, of prostheses using ultrasonic techniques similar to those used for natural teeth A61C17/20; application of ultrasonic vibrations to chemical, physical or physico-chemical processes in general B01J19/10
• CPC Class Codes: H01J 37/32862 In situ cleaning of vessels and/or internal parts
• CPC Class Codes: H01L 21/67028 for cleaning followed by drying, rinsing, stripping, blasting or the like
• CPC Class Codes: H01L 21/6831 using electrostatic chucks

Abstract

To clean an element in a vacuum chamber by causing particles sticking to the element to scatter, the present invention uses a means for applying a voltage to the element and causing the particles to scatter by utilizing Maxwell'"'"'s stress, a means for electrically charging the particles and causing the particles to scatter by utilizing the Coulomb force, a means for introducing a gas into the vacuum chamber and causing the particles sticking to the element to scatter by causing a gas shock wave to hit the element, a means for heating the element and causing the particles to scatter by utilizing the thermal stress and thermophoretic force, or a means for causing the particles to scatter by applying mechanical vibrations to the element. The thus scattered particles are removed by carrying them in a gas flow in a relatively high pressure atmosphere.

Claims

1. An element cleaning method which causes particles sticking to an element in a vacuum chamber to scatter, comprising steps of:

maintaining the vacuum chamber at a pressure equal to or less than 1.3×

10<sup>−

2</sup> Pa;

electrically charging the particles sticking to the element;

scattering the particles sticking to the element by applying to the element a voltage of the same polarity as the charge of the charged particles;

introducing gas into the vacuum chamber while evacuating the vacuum chamber; and

removing the scattered particles by a flow of the introduced gas while the vacuum chamber is evacuated and maintained at a pressure equal to or more than 1.3×

10³ Pa.

2. The element cleaning method according to claim 1, wherein the charging step comprises generating plasma in a space above the element.

3. The element cleaning method according to claim 1, wherein the charging step comprises applying ultraviolet light or vacuum ultraviolet light onto a surface of the element.

4. The element cleaning method according to claim 1, wherein the charging step comprises applying electrons, positrons, or ions to a surface of the element.

5. The element cleaning method according to claim 1, wherein the charging step comprises applying an X ray or a soft X ray to a surface of the element.

6. The element cleaning method according to claim 1, wherein the element is a stage for mounting thereon a substrate to be processed.

7. An element cleaning method for scattering and removing particles sticking to an element in a vacuum chamber, comprising the steps of:

maintaining the vacuum chamber at a pressure equal to or less than 1.3×

10<sup>−

2</sup> Pa;

scattering the particles sticking to the element by utilizing a thermal stress and a thermophoretic force induced by controlling the temperature of the element;

introducing gas into the vacuum chamber while evacuating the vacuum chamber; and

removing the scattered particles by a flow of the introduced gas while the vacuum chamber is evacuated and maintained at a pressure equal to or more than 1.3×

10³ Pa.

8. The element cleaning method according to claim 7, wherein the temperature of the element is set sufficiently higher than normal operating temperature.

9. The element cleaning method according to claim 7, wherein a temperature gradient in a space above the element is controlled to be intensified.

10. The element cleaning method according to claim 9, wherein cool gas is introduced in order to intensify the temperature gradient in the space above the element.

11. The element cleaning method according to claim 7, wherein the element is a stage for mounting thereon a substrate to be processed.

12. An element cleaning method for scattering and removing particles sticking to an element in a vacuum chamber, comprising the steps of:

maintaining the vacuum chamber at a pressure equal to or less than 1.3×

10<sup>−

2</sup> Pa;

scattering the particles sticking to the element by applying a voltage to the element, the voltage determined by a permittivity difference between the element and the particles;

introducing gas into the vacuum chamber while evacuating the vacuum chamber; and

removing the scattered particles by a flow of the introduced gas while the vacuum chamber is evacuated and maintained at a pressure equal to or more than 1.3×

10³ Pa.

13. The element cleaning method according to claim 12, wherein the voltage is a voltage that cycles on and off repeatedly.

14. The element cleaning method according to claim 12, wherein the voltage is an AC voltage.

15. The element cleaning method according to claim 12, wherein the element is a stage for mounting thereon a substrate to be processed.

16. An element cleaning method for scattering and removing particles sticking to an element in a vacuum chamber, comprising the steps of:

maintaining the vacuum chamber at a pressure equal to or less than 1.3×

10<sup>−

2</sup> Pa;

scattering the particles sticking to the element by applying mechanical vibrations to the element;

introducing gas into the vacuum chamber while evacuating the vacuum chamber; and

removing the scattered particles by a flow of the introduced gas while the vacuum chamber is evacuated and maintained at a pressure equal to or more than 1.3×

10³ Pa.

17. The element cleaning method according to claim 16, wherein the mechanical vibrations are generated by ultrasonic vibrations.

18. The element cleaning method according to claim 16, wherein the element is movable and the mechanical vibrations are generated by the movement of the element.

19. The element cleaning method according to claim 16, wherein the element is a stage for mounting thereon a substrate to be processed.