EXTREME ULTRA VIOLET LIGHT SOURCE APPARATUS
In a laser produced plasma type extreme ultra violet light source apparatus, charged particles such as ions emitted from plasma can be efficiently ejected by the action of a magnetic field and secondary production of contaminants can be suppressed. The extreme ultra violet light source apparatus includes: a target nozzle for supplying a target material; a laser oscillator for applying a laser beam to the target material supplied by the target nozzle to generate plasma; an EUV collector mirror for collecting extreme ultra violet light radiated from the plasma; and an electromagnet for forming a magnetic field in a position where the laser beam is applied to the target material, wherein an aperture of the electromagnet is formed according to a shape of lines of magnetic flux of the magnetic field.
1 . A laser produced plasma type extreme ultra violet light source apparatus comprising:
a target nozzle for supplying a target material;
a laser oscillator for applying a laser beam to the target material supplied by said target nozzle to generate plasma;
a collecting optics for collecting extreme ultra violet light radiated from the plasma; and
magnetic field forming means for forming a magnetic field in a position where the laser beam is applied to said target material, wherein an aperture of said magnetic field forming means is formed according to a shape of lines of magnetic flux of the magnetic field.
2 . The extreme ultra violet light source apparatus according to claim 1 , wherein an inner wall surface of the aperture has a shape along the lines of the magnetic flux.
3 . The extreme ultra violet light source apparatus according to claim 1 , wherein an inner wall surface of the aperture has one of a truncated conical shape and a funnel shape.
4 . The extreme ultra violet light source apparatus according to claim 1 , wherein said magnetic field forming means forms an asymmetric magnetic field relative to a surface orthogonal to a central axis of the lines of the magnetic flux.
5 . The extreme ultra violet light source apparatus according to claim 1 , wherein said magnetic field forming means includes a yoke.
6 . The extreme ultra violet light source apparatus according to claim 1 , wherein said magnetic field forming means includes a permanent magnet.
7 . The extreme ultra violet light source apparatus according to claim 1 , wherein said magnetic field forming means includes a superconducting magnet.
8 . The extreme ultra violet light source apparatus according to claim 1 , further comprising:
exhausting means provided to be connected to the aperture of said magnetic field forming means.
9 . The extreme ultra violet light source apparatus according to claim 1 , wherein said magnetic field forming means includes two electromagnets provided in an area corresponding to an angle range in which the EUV light collected by said collecting optics is not used in an exposure unit, and an aperture of each of said two electromagnets is formed according to the shape of lines of magnetic flux of the magnetic field.