Radiation source

Patent metadata

Field	Value
Publication number	US-9366967-B2
Application number	US-201214241364-A
Country	US
Kind code	B2
Filing date	Aug 1, 2012
Priority date	Sep 2, 2011
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

A radiation source ( 60 ) suitable for providing a beam of radiation to an illuminator of a lithographic apparatus. The radiation source comprises a nozzle configured to direct a stream of fuel droplets ( 62 ) along a trajectory ( 64 ) towards a plasma formation location ( 66 ). The radiation source is configured to receive a first amount of radiation ( 68 ) such that the first amount of radiation is incident on a fuel droplet ( 62 a ) at the plasma formation location, and such that the first amount of radiation transfers energy into the fuel droplet to generate a modified fuel distribution ( 70 ), the modified fuel distribution having a surface. The radiation source is also configured to receive a second amount of radiation ( 72 ) such that the second amount of radiation is incident on a portion of the surface ( 70 a ) of the modified fuel distribution, the second amount of radiation having a p-polarized component with respect to the portion of the surface; and such that the second amount of radiation transfers energy to the modified fuel distribution to generate a radiation generating plasma, the radiation generating plasma emitting a third amount of radiation ( 74 ). The radiation source further comprises a collector (CO) configured to collect and direct at least a portion of the third amount of radiation. The radiation source is configured such that the second amount of radiation propagates in a first direction, the first direction being non-parallel to a normal to the portion of the surface of the modified fuel distribution.

First claim

The invention claimed is:

1. A radiation source suitable for providing a beam of radiation to an illuminator of a lithographic apparatus, the radiation source comprising:
a nozzle configured to direct a stream of fuel droplets along a trajectory towards a plasma formation location; and
the radiation source being configured to receive a first amount of radiation such that the first amount of radiation is incident on a fuel droplet at the plasma formation location, and such that the first amount of radiation transfers energy into the fuel droplet to generate a modified fuel distribution, the modified fuel distribution having a surface;
the radiation source being configured to receive a second amount of radiation such that the second amount of radiation is incident on a portion of the surface of the modified fuel distribution, wherein
the second amount of radiation has a p-polarized component with respect to the portion of the surface,
a controller configured to determine a range of angles between (i) a first direction, at which the second amount of radiation propagates, and (ii) a normal to the portion of the surface of the modified fuel distribution at which a maximum amount of energy is transferred from the second amount of radiation to the modified fuel distribution due to plasma resonance, the first direction being non-parallel to the normal to the portion of the surface of the modified fuel distribution, and
the second amount of radiation propagates in the first direction, at which the maximum amount of energy is transferred, and transfers energy to the modified fuel distribution to generate a radiation generating plasma, the radiation generating plasma emitting a third amount of radiation; and

the radiation source further comprising a collector configured to collect and direct at least a portion of the third amount of radiation.

2. The radiation source of claim 1 , wherein the radiation source comprises at least one secondary radiation source, the at least one secondary radiation source generating the first and second amounts of radiation.

3. The radiation source of claim 2 , wherein the at least one secondary radiation source comprises a first secondary radiation source and a second secondary radiation source, the first secondary radiation source being configured to generate the first amount of radiation and the second secondary radiation source configured to generate the second amount of radiation.

4. The radiation source of claim 2 , wherein the at least one secondary radiation source comprises a CO2 or YAG laser.

5. The radiation source of claim 1 , wherein the radiation source is configured such that the angle between the first direction and the normal to the portion of the surface of the modified fuel distribution is between about 10° and about 30°.

6. The radiation source of claim 1 , wherein the radiation source is configured such that the second amount of radiation is one of linearly p-polarized, circularly polarized or randomly polarized.

7. The radiation source of claim 1 , wherein the radiation source is configured such that the modified fuel distribution is generally disk shaped and the portion of the surface of the modified fuel distribution is generally planar.

8. The radiation source of claim 1 , wherein the radiation source is configured such that the modified fuel distribution is generally conical or of a generally spherical cap shape, the portion of the surface modified fuel distribution being a generally conical surface or is generally the surface of a spherical cap respectively.

9. The radiation source of claim 1 , wherein the fuel droplets comprise xenon, tin or lithium.

10. A lithographic apparatus arranged to project a pattern from a patterning device onto a substrate, wherein the lithographic apparatus comprises at least one secondary radiation source and a radiation source configured to provide a beam of radiation to the patterning device along an optical axis, the radiation source comprising:
a nozzle configured to direct a stream of fuel droplets along a trajectory towards a plasma formation location; and
the radiation source being configured to receive a first amount of radiation from the at least one secondary radiation source such that the first amount of radiation is incident on a fuel droplet at the plasma formation location, and such that the first amount of radiation transfers energy into the fuel droplet to generate a modified fuel distribution, the modified fuel distribution having a surface;
the radiation source being configured to receive a second amount of radiation from the at least one secondary radiation source such that the second amount of radiation is incident on a portion of the surface of the modified fuel distribution, wherein
the second amount of radiation has a p-polarized component with respect to the portion of the surface,
a controller configured to determine a range of angles between (i) a first direction, at which the second amount of radiation propagates, and (ii) a normal to the portion of the surface of the modified fuel distribution at which a maximum amount of energy is transferred from the second amount of radiation to the modified fuel distribution due to plasma resonance, the first direction being non-parallel to the normal to the portion of the surface of the modified fuel distribution, and
the second amount of radiation propagates in the first direction, at which the maximum amount of energy is transferred, and transfers energy to the modified fuel distribution to generate a radiation generating plasma, the radiation generating plasma emitting a third amount of radiation; and

the radiation source further comprising a collector configured to collect and direct at least a portion of the third amount of radiation along the optical axis towards the patterning device.

11. The lithographic apparatus of claim 10 , wherein the normal to the portion of the surface of the modified fuel distribution is parallel to the optical axis.

12. The lithographic apparatus of claim 10 , wherein the first direction is parallel to the optical axis.

13. A device manufacturing method using a lithographic apparatus, the lithographic apparatus comprising at least one secondary radiation source, a patterning device and a radiation source having a nozzle, a plasma formation location and a collector, the method comprising:
directing a stream of fuel droplets from the nozzle along a trajectory towards the plasma formation location;
producing a first amount of radiation from the at least one radiation source such that the first amount of radiation is incident on a fuel droplet at the plasma formation location;
transferring energy from the first amount of radiation into the fuel droplet to generate a modified fuel distribution, the modified fuel distribution having a surface;
producing a second amount of radiation having a p-polarized component with respect to a portion of the surface from the at least one radiation source such that the second amount of radiation is incident on the portion of the surface of the modified fuel distribution, wherein the second amount of radiation propagates in a first direction, the first direction being non-parallel to a normal to the portion of the surface of the modified fuel distribution;
determining an angle between the first direction and the normal to the portion of the surface of the modified fuel distribution at which a maximum amount of energy is transferred from the second amount of radiation to the modified fuel distribution due to plasma resonance, wherein the second amount of radiation propagates in the first direction at the angle at which the maximum amount of energy

Assignees

• Yakunin Andrei Mikhailovich
• Ivanov Vladimir Vitalevich
• Krivtsun Vladimir Mihailovitch
• Medvedev Viacheslav
• Swinkels Gerardus Hubertus Petrus Maria
• Van Schoot Jan Bernard Plechelmus
• Asml Netherlands Bv

Inventors

• Yakunin Andrei Mikhailovich
• Ivanov Vladimir Vitalevich
• Krivtsun Vladimir Mihailovitch
• Medvedev Viacheslav
• Swinkels Gerardus Hubertus Petrus Maria
• Van Schoot Jan Bernard Plechelmus

Classifications

• H05G2/0086

  Optical arrangements for conveying the laser beam to the plasma generation location · CPC title

• H05G2/0088

  for preconditioning the plasma generating material · CPC title

• H05G2/006

  Electricity · mapped topic

• H05G2/008

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

• H05G2/005

  Electricity · mapped topic