Radiation collector, radiation source and lithographic apparatus

Patent metadata

Field	Value
Publication number	US-9983482-B2
Application number	US-201414775263-A
Country	US
Kind code	B2
Filing date	Feb 26, 2014
Priority date	Mar 27, 2013
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

A radiation collector comprising a first collector segment comprising a plurality of grazing incidence reflector shells configured to direct radiation to converge in a first location at a distance from the radiation collector, a second collector segment comprising a plurality of grazing incidence reflector shells configured to direct radiation to converge in a second location at said distance from the radiation collector, wherein the first location and the second location are separated from one another.

First claim

The invention claimed is:

1. A radiation collector comprising:
a first collector segment comprising a plurality of grazing incidence reflector shells configured to direct radiation to substantially converge in a first location at a distance from the radiation collector; and
a second collector segment comprising a plurality of grazing incidence reflector shells configured to direct a second portion of the radiation to substantially converge in a second location at said distance from the radiation collector;
wherein the first location and the second location are separated from one another,
wherein the radiation directed by the radiation collector defines a volume up to the first and second locations through which substantially no radiation directed by the radiation collector passes, and
wherein a cross-sectional area of the volume increases with distance from the radiation collector.

2. The radiation collector of claim 1 further comprising at least one additional collector segment, wherein each additional collector segment comprises a plurality of grazing incidence reflector shells configured to direct respective portions of radiation to substantially converge in a location at said distance from the radiation collector, wherein the location of each additional collector segment is separate from the respective locations of the other collector segments.

3. The radiation collector of claim 1 , wherein the collector segments are disposed around an optical axis of the radiation collector.

4. The radiation collector of claim 3 , wherein each collector segment comprises a respective angular portion of the radiation collector.

5. The radiation collector of claim 3 , wherein the radiation collector extends substantially circumferentially around the optical axis.

6. The radiation collector according to claim 3 , wherein the first and second location are situated substantially equidistant from the optical axis.

7. The radiation collector according to claim 1 , wherein the radiation directed by the first collector segment to the first location forms a first intensity distribution of radiation at a far-field location, and the radiation directed by the second collector segment to the second location forms a second intensity distribution of radiation at the far-field location.

8. The radiation collector according to claim 7 , wherein there is substantially no overlap between the first intensity distribution and the second intensity distribution at the far field location.

9. A radiation source comprising:
a fuel source configured to deliver fuel to a location from which the fuel emits EUV radiation; and
a radiation collector comprising:
a first collector segment comprising a plurality of grazing incidence reflector shells configured to direct a first portion of radiation to substantially converge in a first location at a distance from the radiation collector; and
a second collector segment comprising a plurality of grazing incidence reflector shells configured to direct a second portion of the radiation to substantially converge in a second location at said distance from the radiation collector;
wherein the first location and the second location are separated from one another,
wherein the radiation directed by the radiation collector defines a volume up to the first and second locations through which substantially no radiation directed by the radiation collector passes, and
wherein a cross-sectional area of the volume increases with distance from the radiation collector.

10. The radiation source of claim 9 , wherein the collector segments are disposed around an optical axis of the radiation collector, and the location from which the fuel emits EUV radiation is positioned on or near the optical axis.

11. The radiation source of claim 9 , wherein the radiation source further comprises a mirror disposed inside the volume, and the mirror is configured to focus a laser beam at the location from which the fuel emits EUV radiation.

12. The radiation source of claim 9 , wherein the radiation source further comprises a contaminant trap in between the fuel source and the radiation collector, wherein the contaminant trap comprises a trap section configured to trap contaminants, and a drive system configured to rotate the trap section about a central axis of the contaminant trap, and wherein at least a part of the drive system is disposed inside the volume.

13. A lithographic apparatus comprising a radiation source configured to project EUV radiation from the radiation source onto a substrate, wherein the radiation source comprises:
a fuel source configured to deliver fuel to a location from which the fuel emits the EUV radiation; and
a radiation collector comprising:
a first collector segment comprising a plurality of grazing incidence reflector shells configured to direct a first portion of radiation to substantially converge in a first location at a distance from the radiation collector; and
a second collector segment comprising a plurality of grazing incidence reflector shells configured to direct a second portion of the radiation to substantially converge in a second location at said distance from the radiation collector;
wherein the first location and the second location are separated from one another,
wherein the radiation directed by the radiation collector defines a volume up to the first and second locations through which substantially no radiation directed by the radiation collector passes, and
wherein a cross-sectional area of the volume increase with distance from the radiation collector.

14. The lithography apparatus of claim 13 , wherein the first and second collector segments are disposed around an optical axis of the radiation collector.

15. The lithography apparatus of claim 14 , wherein the first and second locations are situated substantially equidistant from the optical axis.

16. The lithography apparatus of claim 14 , wherein the radiation collector extends substantially circumferentially around the optical axis.

17. The lithography apparatus of claim 13 , wherein the radiation directed by the first collector segment to the first location forms a first intensity distribution of radiation at a far-field location, and the radiation directed by the second collector segment to the second location forms a second intensity distribution of radiation at the far-field location.

18. The lithography apparatus of claim 17 , wherein there is substantially no overlap between the first and second intensity distributions at the far field location.

Assignees

• Asml Netherlands Bv
• Zeiss Carl Smt Gmbh

Inventors

• Loopstra Erik Roelof
• Frijns Olav Waldemar Vladimir
• Bieling Stig
• Kempen Antonius Theodorus Wilhelmus
• Vanderhallen Ivo
• Ten Kate Nicolaas
• Beerens Ruud Antonius Catharina Maria
• Van Lieshout Richard Henricus Adrianus
• Cadee Theodorus Petrus Maria
• Donders Sjoerd Nicolaas Lambertus
• Struycken Alexander Matthijs
• Scheepers Marcus Petrus

Classifications

• H05G2/003

  the plasma being generated from a material in a liquid or gas state · CPC title

• G03F7/70916

  Pollution mitigation, i.e. mitigating effect of contamination or debris, e.g. foil traps · CPC title

• G03F7/70166

  Capillary or channel elements, e.g. nested extreme ultraviolet [EUV] mirrors or shells, optical fibers or light guides · CPC title

• G02B5/0891

  Ultraviolet [UV] mirrors (apparatus for microlithography exposure G03F7/70; X-ray multilayer structures G21K1/06) · CPC title

• G03F7/702

  Reflective illumination, i.e. reflective optical elements other than folding mirrors, e.g. extreme ultraviolet [EUV] illumination systems · CPC title