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AssigneeASML Netherlands B.V.
InventorsSietse Thijmen VAN DER POST, Sander Bas ROOBOL, Pavel EVTUSHENKO
Estimating the term…
A radiation source arrangement causes interaction between pump radiation (340) and a gaseous medium (406) to generate EUV or soft x-ray radiation by higher harmonic generation (HHG). The operating condition of the radiation source arrangement is monitored by detecting (420/430) third radiation (422) resulting from an interaction between condition sensing radiation and the medium. The condition sensing radiation (740) may be the same as the first radiation or it may be separately applied. The third radiation may be for example a portion of the condition sensing radiation that is reflected or scattered by a vacuum-gas boundary, or it may be lower harmonics of the HHG process, or fluorescence, or scattered. The sensor may include one or more image detectors so that spatial distribution of intensity and/or the angular distribution of the third radiation may be analyzed. Feedback control based on the determined operating condition stabilizes operation of the HHG source.
1-58. (canceled)
A radiation source arrangement operable to cause an interaction between first radiation and a medium and thereby to generate second radiation by higher harmonic generation, the radiation source arrangement further comprising:
An inspection apparatus comprising:
A method of monitoring an operating condition of a radiation source arrangement, the radiation source arrangement causing an interaction between first radiation and a medium and thereby to generate second radiation by higher harmonic generation, the method comprising:
Dependencies are inferred from the claim text.