METHOD AND DEVICE FOR CLEANING AT LEAST ONE OPTICAL COMPONENT

• US 20110048452A1
• Filed: 05/18/2004
• Published: 03/03/2011
• Est. Priority Date: 05/22/2003
• Status: Active Grant

• Current Assignee: Ushio Denki Kabushiki Kaisha
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Weber, Achim, Zink, Peter, Derra, Guenther Hans, Pankert, Joseph Robert Rene
• Granted Patent: US 8,945,310 B2
• Time in Patent Office: Days
• US Class Current: 134/1
• CPC Class Codes: B08B 7/00 Cleaning by methods not provided for in a single other subclass or a single group in this subclass
• CPC Class Codes: B08B 7/0057 by ultraviolet radiation
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G03F 7/70166 Capillary or channel elements, e.g. nested extreme ultraviolet [EUV] mirrors or shells, optical fibers or light guides
• CPC Class Codes: G03F 7/70925 Cleaning, i.e. actively freeing apparatus from pollutants, e.g. using plasma cleaning
• CPC Class Codes: G03F 7/70941 Stray fields and charges, e.g. stray light, scattered light, flare, transmission loss
• CPC Class Codes: G21K 1/06 using diffraction, refraction or reflection, e.g. monochromators G21K1/10, G21K7/00 take precedence

Abstract

A method of cleaning at least one optical component of at least one irradiation device is described, which device comprises at least one radiation source in a vacuum chamber, which source generates in particular extreme ultraviolet and/or soft X-ray radiation whose rays are guided via the optical component onto a workpiece to be treated, during which said optical component is at least partly polluted because of an inorganic substance introduced by the radiation source.

It is proposed that at least one reaction partner (124) that is substantially translucent or transparent to the rays (118) be introduced via a feeder device (126) in dependence on the prevailing reaction conditions, which reaction partner (124) reacts chemically with the polluting deposits (128) so as to remove them from the optical component (110).

Claims

1. A method of cleaning at least one optical component (110;

43) of at least one irradiation device (112) which comprises at least one radiation source (116) in a vacuum chamber (114), which source (116) generates in particular extreme ultraviolet and/or soft X-ray radiation whose rays (118) are guided via the optical component (110) onto a workpiece (120) to be treated, during which said optical component (110) is at least partly polluted because of an inorganic substance (122) introduced by the radiation source (116), characterized in that at least one reaction partner (124) that is substantially translucent or transparent to the rays (118) is introduced via a feeder device (126) in dependence on the prevailing reaction conditions, which reaction partner (124) reacts chemically with the polluting deposits (128) so as to remove them from the optical component (110), wherein the reaction partner (124) is fed in via a dispensing device (132) in an excess quantity with respect to an introduced quantity of inorganic substance (122) and/or the deposits (128) or at a rate of up to the chemical equivalent of an introduced quantity of inorganic substance (122) and/or deposits (128).

2. A method as claimed in claim 1, characterized in that the reaction partner (124) is focused on the optical component (110).

3. A method as claimed in claim 1 or 2, characterized in that components of the irradiation device that are not to be cleaned are protected against contact with the reaction partner (124) or the cleaning gas (42).

4. A method as claimed in claim 1, characterized in that the optical components (110;

43) to be cleaned are separated from the remainder of the vacuum system for the duration of the cleaning process.

5. A method of cleaning at least one optical component (110;

43) of at least one irradiation device (112) which comprises at least one radiation source (116) in a vacuum chamber (114), which source (116) generates in particular extreme ultraviolet and/or soft X-ray radiation whose rays (118) are guided via the optical component (110) onto a workpiece (120) to be treated, during which said optical component (110) is at least partly polluted because of an inorganic substance (122) introduced by the radiation source (116), in particular as claimed in one of the claims 1 to 4, characterized in that the introduced inorganic substances (122, 45) are suppressed by means of a foil trap (10) between the radiation source (1) and the collector (3).

6. A method as claimed in claim 5, characterized in that a blocking gas (20′

) of a gas type different from that of a buffer gas (20) of the foil trap (10) is additionally provided in the region of the radiation source (1) and/or the region of the collector (3), which blocking gas comprises, for example, at least hydrogen, nitrogen, helium, or some other rare gas.

7. A method as claimed in claim 5 or 6, characterized in that electrical and/or magnetic fields are applied for the suppression of deposits (128, 45).

8. A method of cleaning at least one optical component (110;

43) of at least one irradiation device (112) which comprises at least one radiation source (116) in a vacuum chamber (114), which source (116) generates in particular extreme ultraviolet and/or soft X-ray radiation whose rays (118) are guided via the optical component (110) onto a workpiece (120) to be treated, during which said optical component (110) is at least partly polluted because of an inorganic substance (122) introduced by the radiation source (116), in particular as claimed in any one of the claims 1 to 7, characterized in that it is electronically controlled and regulated.

9. A method as claimed in claim 8, characterized in that the degree of contamination of the optical component (110;

43) is measured subject to requirement or continuously.

10. A method as claimed in claim 9, characterized in that the degree of contamination is measured in several locations.

11. A device for cleaning at least one optical component (110) of at least one irradiation device (112) which comprises in a vacuum chamber (114) at least one radiation source (116) that generates in particular extreme ultraviolet and/or soft X-ray radiation and an optical component (110), which direct rays (118) towards a workpiece (120) to be processed, which optical component (110) may be polluted at least partly because of an inorganic substance (122) introduced by the radiation source (116), characterized in that a feeder device (126) is present for eliminating deposits (128) which pollute the optical component (110), which feeder device (126) introduces at least one reaction partner (124) in dependence on the prevailing reaction conditions, which reaction partner (124) is substantially permeable or transparent to said rays (118) and enters into a chemical reaction with the polluting deposits (128), wherein the reaction partner (124) can be fed in via a dispensing device (132) in an excess quantity or at a rate of up to the chemical equivalent with respect to an introduced quantity of inorganic substance (122) and/or the deposits (128).

12. A device as claimed in claim 11, characterized in that the feeder device (126) comprises a cooling device (138) and/or a nozzle (140).

13. A device as claimed in claim 11, characterized in that at least one optical component (110) comprises a heating device (146), and/or in that the components of the vacuum system that are not to be cleaned can be cooled.

14. A device for cleaning at least one optical component (110) of at least one irradiation device (112) which comprises in a vacuum chamber (114) at least one radiation source (116) generating in particular extreme ultraviolet and/or soft X-ray radiation and an optical component (110), which direct rays (118) towards a workpiece (120) to be processed, which optical component (110) may be polluted at least partly because of an inorganic substance (122) introduced by the radiation source (116), in particular as claimed in any one of the claims 11 to 13, characterized in that a foil trap (10) is arranged between the radiation source (1) and the collector (3).

15. A device as claimed in claim 14, characterized in that the foil trap (10) or part of the foil trap (10) can be set into rotation.

16. A device as claimed in claim 15, characterized in that a stationary or rotatable catchment device (15) is arranged around the edge of the rotatable foil trap (10).

17. A device as claimed in claim 14, characterized in that the cleaning can be carried out under an electronic control.

18. A device as claimed in claim 17, characterized in that the degree of contamination of the optical component (110;

43) can be measured by means of devices arranged in several locations.