Extreme ultraviolet light source

Patent metadata

Field	Value
Publication number	US-10667377-B2
Application number	US-201514979657-A
Country	US
Kind code	B2
Filing date	Dec 28, 2015
Priority date	Jan 22, 2014
Publication date	May 26, 2020
Grant date	May 26, 2020

Abstract

A target material is provided at a target location, the target material including a material that emits extreme ultraviolet light when converted to plasma, and the target material extending in a first extent along a first direction and in a second extent along a second direction; an amplified light beam is directed along a direction of propagation toward the target location; and the amplified light beam is focused in a focal plane, where the target location is outside of the focal plane and an interaction between the amplified light beam and the target material converts at least part of the target material to plasma that emits EUV light.

First claim

What is claimed is:

1. A method comprising:
directing a target along a target path toward a target location in a vacuum chamber, the target comprising target material in a geometric distribution that comprises a first extent in a first dimension, the first dimension being along a first direction, and a second extent in a second dimension, the second dimension being along a second direction, the first and second direction being orthogonal directions, the second extent being greater than the first extent; and
directing an amplified light beam toward the target location, the amplified light beam traveling along a propagation path and having an energy sufficient to convert at least some of the target material in the target to a plasma that emits EUV light, wherein
the propagation path and the target path are non-orthogonal at the target location,
a portion of the target that extends in the second direction receives the amplified light beam, and
the propagation path and the second direction are non-orthogonal at the target location such that a reflection produced by an interaction between the amplified light beam and the portion of the target propagates away from the target along the first direction.

2. The method of claim 1 , wherein the geometric distribution of the target material is substantially disk shaped.

3. The method of claim 2 , wherein the target path is along the second direction at the target location.

4. The method of claim 1 , wherein directing a target along a target path comprises directing a plurality of targets along the target path.

5. The method of claim 4 , wherein the geometric distributions of the targets are substantially disk shaped.

6. The method of claim 5 , further comprising forming the substantially disk shaped geometric distributions.

7. The method of claim 6 , wherein the substantially disk shaped geometric distributions are formed outside of the target location.

8. The method of claim 7 , further comprising directing a first beam of light toward the target path prior to directing the amplified light beam toward the target location, the first beam of light having an energy that is less than the energy of the amplified light beam, and wherein an interaction between a target of the plurality of targets and the first beam forms the substantially disk shaped geometric distribution of target material.

9. The method of claim 1 , wherein the target material comprises a metallic material.

10. The method of claim 9 , wherein the target material comprises tin.

11. The method of claim 1 , wherein the amplified light beam has a wavelength of 10.6 microns (μm).

12. The method of claim 1 , wherein the reflection is one or more of a reflection of the amplified light beam from the target and a reflection of the amplified light beam from the plasma.

13. A system comprising:
a vacuum chamber configured to receive an amplified light beam; and
a target material supply system configured to provide a target comprising target material arranged in a geometric distribution, the target traveling along a target path to a target location in the vacuum chamber, the target material emitting EUV light when in a plasma state, wherein
the amplified light beam has an energy sufficient to convert at least some of the target material in the target to plasma that emits EUV light,
the amplified light beam propagates along a propagation path,
a portion of the target that extends along a second direction receives the amplified light beam, the target having an extent along the second direction that is greater than an extent along an orthogonal first direction,
the target path and the propagation path are non-orthogonal at the target location, and
the propagation path and the second direction are non-orthogonal at the target location such that a reflection produced by an interaction between the amplified light beam and the portion of the target propagates away from the target along the first direction.

14. The system of claim 13 , further comprising an optical element in the vacuum chamber, the optical element being positioned to receive EUV light emitted from the target location.

15. The system of claim 14 , wherein the optical element comprises a collector mirror, the collector mirror comprising a surface that reflects EUV light.

16. The system of claim 15 , wherein the collector mirror defines an aperture, and the propagation path of the amplified light beam passes through the aperture.

17. The system of claim 16 , wherein the collector mirror defines a first focal point and an intermediate focal point, and the target location at least partially coincides with the first focal point, and at least some of the EUV light emitted from the target location is reflected from the reflective surface of the collector mirror and focused at the second focal point.

18. The system of claim 13 , wherein the target material supply apparatus is configured to provide substantially disk shaped targets.

19. The system of claim 13 , further comprising an optical source configured to emit the amplified light beam.

20. The system of claim 19 , wherein the system comprises a plurality of optical sources, at least one of which comprises a solid state laser.

21. The system of claim 19 , wherein the optical source comprises a carbon dioxide (CO 2 ) laser.

22. A photolithography system comprising:
a lithography tool configured to process wafers; and
an extreme ultraviolet light source comprising:
a vacuum chamber configured to receive a target in an interior of the vacuum chamber at a target location, the target comprising a target material that emits extreme ultraviolet (EUV) light when converted to plasma;
an optical source configured to produce pulses of radiation, the pulses of radiation comprising at least a first pulse of radiation and a second pulse of radiation, at least one of the first pulse of radiation and the second pulse of radiation having an energy sufficient to convert at least some of the target material in the target to a plasma that emits EUV light; and
an EUV collecting optic in the vacuum chamber configured to direct EUV light emitted by the plasma to the lithography tool, wherein
the first pulse of radiation and the second pulse of radiation propagate along a propagation path,
the target travels along a target path,
the target has a first extent in a first dimension, the first dimension being along a first direction, and a second extent in a second dimension, the second dimension being along a second direction, the second extent being greater than the first extent, the first direction being orthogonal to the second direction,
the target is positioned to receive one of the first pulse and the second pulse at a portion that extends in the second direction,
the propagation path and the target path are non-orthogonal at the target location, and
the second direction and the propagation path are non-orthogonal at the target location such that a reflection produced by an interaction between the amplified light beam and the portion of the target propagates away from the target along the first direction.

Assignees

• Asml Netherlands Bv

Inventors

• Rafac Robert Jay
• Sandstrom Richard L
• Brown Daniel John William
• Hou Kai-Chung

Classifications

• G03F7/70033

  by plasma extreme ultraviolet [EUV] sources · CPC title

• G03F7/70058

  Mask illumination systems · CPC title

• H05G2/008 Primary

  involving an energy-carrying beam in the process of plasma generation · CPC title

• G03F7/2008

  characterised by the reflectors, diffusers, light or heat filtering means or anti-reflective means used · CPC title

• H05G2/0082 Primary

  the energy-carrying beam being a laser beam · CPC title