Patent Number: 
Section: claims

1. An extreme ultraviolet light source apparatus comprising a vacuum chamber, a target supply unit supplying a target into the vacuum chamber, a laser oscillator outputting a laser light into the vacuum chamber, and a collector mirror outputting an extreme ultraviolet light outside by reflecting the extreme ultraviolet light emitted from the target being ionized as a plasma by irradiation with the laser light at a plasma luminescence point in the vacuum chamber, the extreme ultraviolet light source apparatus comprising:an ion debris removal unit at least a part of which is located in an obscuration region including the plasma luminescence point. 2. The extreme ultraviolet light source apparatus according to claim 1, further comprising:a support member supporting the ion debris removal unit from an inner wall of the vacuum chamber, whereinat least a part of the support member is located in the obscuration region. 3. The extreme ultraviolet light source apparatus according to claim 1, whereinthe ion debris removal unit includes a magnetic field generator located near the plasma luminescence point, the magnetic field generator generating a magnetic field for trapping ion debris. 4. The extreme ultraviolet light source apparatus according to claim 3, whereinthe magnetic field generator is a pair of magnets facing each other while sandwiching the plasma luminescence point in between. 5. The extreme ultraviolet light source apparatus according to claim 3, further comprising:a collection (receiving) portion collecting (receiving) ion debris trapped by the magnetic field generator. 6. The extreme ultraviolet light source apparatus according to claim 5, further comprising:a support member supporting the collection (receiving) portion from an inner wall of the vacuum chamber, whereinat least a part of the support member is located in the obscuration region. 7. The extreme ultraviolet light source apparatus according to claim 5, whereinthe collection (receiving) portion includes a collection tube disemboguing ion debris outside the vacuum chamber for collecting the ion debris, andthe collection (receiving) portion and the collection tube have temperature regulators maintaining a temperature of the ion debris at a melting temperature of the ion debris. 8. The extreme ultraviolet light source apparatus according to claim 5, whereinthe collection (receiving) portion collects (receives) the ion debris via an inside of a bore of the magnetic field generator. 9. The extreme ultraviolet light source apparatus according to claim 5, whereinat least a part of the collection (receiving) portion is located in the obscuration region. 10. The extreme ultraviolet light source apparatus according to claim 2, whereinthe magnetic field generator includes a pair of magnets located outside the obscuration region in such a way as to face each other while sandwiching the plasma luminescence point in between, and magnetic cores extending inside the obscuration region from the magnets, respectively. 11. The extreme ultraviolet light source apparatus according to claim 10, whereinthe magnetic core is coated with a coating layer. 12. The extreme ultraviolet light source apparatus according to claim 10, further comprising:a collection (receiving) portion collecting (receiving) ion debris trapped by the magnetic field generator, whereina shape of the magnetic core is cylindrical, andthe collection (receiving) portion is located inside the magnetic core being cylindrical. 13. The extreme ultraviolet light source apparatus according to claim 12, further comprising:a support member supporting the collection (receiving) portion from an inner wall of the vacuum chamber, whereinat least a part of the support member is located in the obscuration region. 14. The extreme ultraviolet light source apparatus according to claim 12, whereinthe collection (receiving) portion includes a collection tube disemboguing ion debris outside the vacuum chamber for collecting the ion debris, andthe collection (receiving) portion and the collection tube have temperature regulators maintaining a temperature of the ion debris at a melting temperature of the ion debris. 15. The extreme ultraviolet light source apparatus according to claim 1, further comprising:an accessorial electrical field generator trapping ion debris, the accessorial electrical field generator being located outside the obscuration region. 16. The extreme ultraviolet light source apparatus according to claim 15, further comprising:a support member supporting the accessorial electrical field generator from an inner wall of the vacuum chamber, whereinat least a part of the support member is located in the obscuration region. 17. The extreme ultraviolet light source apparatus according to claim 1, whereinthe ion debris removal unit includes an electrical field generator which is located near the plasma luminescence point, the electrical field generator generating an electrical field for trapping ion debris. 18. The extreme ultraviolet light source apparatus according to claim 17, whereinthe electrical field generator is an electrostatic grid located at a space lying on an incident side of the laser light, the space including the plasma luminescence point. 19. The extreme ultraviolet light source apparatus according to claim 18, further comprising:a collection (receiving) portion collecting (receiving) ion debris trapped by the electrical field generator. 20. The extreme ultraviolet light source apparatus according to claim 19, wherein the collection (receiving) portion includes a collection tube disemboguing ion debris outside the vacuum chamber for collecting the ion debris, andthe collection (receiving) portion and the collection tube have temperature regulators maintaining a temperature of the ion debris at a melting temperature of the ion debris. 21. The extreme ultraviolet light source apparatus according to claim 19, whereinat least a part of the collection (receiving) portion is located in the obscuration region. 22. The extreme ultraviolet light source apparatus according to claim 21, further comprising:a support member supporting the collection (receiving) portion from an inner wall of the vacuum chamber, whereinat least a part of the support member is located in the obscuration region. 23. An extreme ultraviolet light source apparatus comprising a vacuum chamber having an optical window for inputting a laser light inside from outside, a target supply supplying a target into the vacuum chamber, and a collector mirror outputting an extreme ultraviolet light outside by reflecting the extreme ultraviolet light emitted from the target being ionized as a plasma by irradiation with the laser light at a plasma luminescence point in the vacuum chamber, the extreme ultraviolet light source apparatus comprising:an ion debris removal unit at least a part of which is located in an obscuration region including the plasma luminescence point.