CPC G21K 1/06 (2013.01) [G02B 5/0808 (2013.01); G02B 5/0891 (2013.01); G02B 5/10 (2013.01); G03F 7/70025 (2013.01); G03F 7/70033 (2013.01); H05G 2/008 (2013.01)] | 20 Claims |
1. A radiation source apparatus, comprising:
a vessel having an exit aperture;
a laser source configured to emit a laser beam to excite a target material to form a plasma;
a collector disposed in the vessel and configured to collect a radiation emitted by the plasma and to reflect the collected radiation to the exit aperture of the vessel;
a horizontal obscuration bar extending from a sidewall of the vessel at least to a position between the laser source and the exit aperture of the vessel; and
a reflective mirror in the vessel and connected to the horizontal obscuration bar.
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