Patent Number: 
Section: claims

1. A radiation system for generating a beam of radiation defining an optical axis, the radiation system comprising:a plasma produced discharge source constructed and arranged to generate extreme ultraviolet radiation, the discharge source comprising a pair of electrodes constructed and arranged to be provided with a voltage difference, and a system constructed and arranged to produce a discharge between said pair of electrodes so as to provide a pinch plasma between said electrodes; anda debris catching shield constructed and arranged to catch debris produced on or near said electrodes in debris producing zones, to shield said electrodes from a line of sight provided in a predetermined spherical angle relative the optical axis, and to provide an aperture to a central area between said electrodes in said line of sight. 2. A radiation system according to claim 1, wherein the debris catching shield comprises at least one fluid jet. 3. A radiation system according to claim 2, wherein the fluid jet comprises molten tin or a tin compound. 4. A radiation system according to claim 3, wherein the tin compound comprises Ga—In—Sn. 5. A radiation system according to claim 1, wherein the debris catching shield is provided by a pair of fluid jets, arranged oppositely and generally parallel to a longitudinal axis of the electrodes. 6. A radiation system according to claim 2, wherein the debris catching shield comprises a plurality of fluid jets, arranged in radial direction relative from the central area. 7. A radiation system according to claim 6, wherein said plurality of fluid jets are provided adjacent to each other. 8. A radiation system according to claim 1, wherein the debris catching shield is provided at a distance from the electrodes ranging between about 0.5 mm and about 25 mm. 9. A radiation system according to claim 1, wherein the debris catching shield is provided by a moving element that moves generally parallel to an electrode longitudinal axis. 10. A radiation system according to claim 9, wherein a container is provided for containing a coolant, for guiding said moving element therethrough. 11. A radiation system according to claim 1, wherein the debris catching shield comprises a static configuration of generally radially oriented platelets, relative to said central area, wherein the platelets are oriented to shield the electrodes from a line of sight provided between said platelets. 12. A radiation system according to claim 11, wherein a distance between the platelets is increased relative to distances away from the optical axis. 13. A radiation system according to claim 11, wherein a distance between the platelets ranges between about 0.5 mm and about 3 mm. 14. A radiation system according to claim 11, further comprising an electromagnetic deflecting field unit disposed for applying an electromagnetic deflecting field between the electrodes and the shield. 15. A radiation system according to claim 14, wherein said electromagnetic deflecting field unit provides a static magnetic field. 16. A radiation system according to claim 15, wherein said magnetic field is provided as a quadrupole field, arranged for deflecting positive particles towards a plane oriented along said radially oriented platelets. 17. A radiation system according to claim 16, wherein said plane is provided along the optic axis. 18. A radiation system according to claim 11, further comprising a hydrogen radical supply system for guiding hydrogen radicals through said platelets. 19. A radiation system according to claim 11, wherein at least some of the platelets are provided with traverses oriented generally transverse to said platelets. 20. A radiation system according to claim 19, further wherein said traverses are provided with wires. 21. A radiation system according to claim 19 further comprising a hydrogen radical supply system for guiding hydrogen radicals through said traverses. 22. A radiation system according to claim 11 wherein at least some of the platelets are provided by a fluid jet. 23. A radiation system according to claim 22, wherein the fluid jet comprises molten tin or a tin compound. 24. A radiation system according to claim 23, wherein the tin compound comprises Ga—In—Sn. 25. A radiation system according to claim 1, further comprising a heating system that can be selectively heated for elevating a temperature of said debris catching shield to a temperature for evaporating said debris from said debris catching shield; and a gas supply system for providing a gas flow to evacuate said evaporated debris from said debris catching shield. 26. A radiation source according to claim 25, wherein said elevation temperature is at least 900° C. to remove tin debris. 27. A radiation source according to claim 25, wherein said elevation temperature is at least 270° C. to remove lithium debris. 28. A radiation system according to claim 1, wherein said plasma source comprises tin, lithium, or xenon. 29. A radiation system according to claim 11, wherein the platelets are provided as a material of porous characteristics for removing said debris from said platelets through capillary action. 30. A radiation system according to claim 11, further comprising an excitator for removing said debris from said platelets through mechanical excitation of said platelets. 31. A radiation system according to claim 30, wherein said excitator comprises a vibrator for providing vibrations to said platelets. 32. A radiation system according to claim 30, wherein said excitator comprises a centrifuge for removing said debris from said platelets through centrifugal action. 33. A radiation system according to claim 30, further comprising a getter for catching debris removed from said platelets. 34. A radiation system according to claim 1, wherein the system that is constructed and arranged to produce a discharge between said pair of electrodes comprises a laser. 35. A lithographic apparatus comprising:a radiation system constructed and arranged to generate a beam of radiation defining an optical axis, the radiation system comprising:a plasma produced discharge source constructed and arranged to generate extreme ultraviolet radiation, the discharge source comprising a pair of electrodes constructed and arranged to be provided with a voltage difference, and a system constructed and arranged to produce a discharge between said pair of electrodes so as to provide a pinch plasma between said electrodes; anda debris catching shield constructed and arranged to catch debris produced on or near said electrodes in debris producing zones, to shield said electrodes from a line of sight provided in a predetermined spherical angle relative the optical axis, and to provide an aperture to a central area between said electrodes in said line of sight;a patterning device constructed and arranged to pattern the beam of radiation; anda projection system constructed and arranged to project the patterned beam of radiation onto a substrate.